Model Engine Maker

Engines => From Plans => Topic started by: kvom on April 24, 2018, 06:01:31 PM

Title: Muncaster Grasshopper - Work in Progress
Post by: kvom on April 24, 2018, 06:01:31 PM
I decided to start a new thread for a build as opposed to keeping on with the discussion of the plans.  As I mentioned in the other thread, I will be using Julius' original SW parts plus any modifications needed to use the two piece beam in V2.

As I wrote in the NAMES thread, I'm going to adopt Cliff Roemmich's idea of using honed hydraulic tubing for the cylinder.  I have ordered a piece of 2" OD x 1.5" ID tube from Bailey Hydraulics of Knoxville TN.  Since the OD is close to the OD of the cylinder itself, this tube will be the cylinder body and not a sleeve.  I had to order the minimum 24", enough for 4 engines.  If anyone else wants to share, I paid $90 for the tube, so a 6" piece would be 22.50 plus shipping.  I'll do an evaluation as soon the piece arrives.  FWIW, this is the 2nd smallest tube they have, and the smaller is 1.875" OD.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on April 26, 2018, 09:36:22 PM
My piece of tube from Bailey arrives this afternoon, so I was able to take the first baby steps in this project.  Here's the raw tube as shipped:

(http://www.pbase.com/kvom/image/167383627/large.jpg)

I cut off ~ 5.25" with the bandsaw, then  mounted on the lathe.  Faced both ends and applied a chamfer to remove the internal burr, then a second face/chamfer to length.  Finally a pass with some Scotch Brite to remove the external mill finish.

(http://www.pbase.com/kvom/image/167383628/large.jpg)

The OD of the tube measures 2.002" and the ID 1.502".

I also ordered a piece of 6061 4" round bar on eBay from which to make the beam mounting bracket.  I noticed that this bracket attaches to the top flange of the cylinder via 6 M4 screws, which means that the matching holes in the flange must be clearance and the holes in the bracket tapped.  But the other two hole in the flange (those over the port block) must be tapped in order to secure the matching holes in the cylinder cover.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on April 27, 2018, 09:02:41 PM
More work on the cylinder.  First, I turned down each end to 1.75" diameter for a length of 8mm.  DRO makes this mix of metric/imperial relatively math free.  The tube sticks out a bit more than I like, but I don't have a live centerlarge enough.  I used the nose of a large drill chuck to align it.

(http://www.pbase.com/kvom/image/167388553/large.jpg)

Now for the bottom flange, I used a length of 3" 6061 bar to turn down the outer diameter to 65mm and the inner to 51x4mm.  Then opened up the center with a 1-3/8" endmill that I've never otherwise used.  Then boring bar to creep up on a sliding fit to the cylinder tube.

(http://www.pbase.com/kvom/image/167388554/large.jpg)

(http://www.pbase.com/kvom/image/167388555/large.jpg)

Then parted off and faced flange to 4mm thickness.  The mounting holes will be drilled and tapped later on.  Then I repeated the operations for the top flange, that differs in being 70mm diameter.

With both flanges done, the assembly was clamped on the Bridgeport's vise, and a flat machined for mounting the port block.  Julius drew the port block with a concave inner surface to match the outer surface of the cylinder, but I feared being able to get an air tight fit that way.  The two steam ports were then drilled with a 5/32 endmill.

(http://www.pbase.com/kvom/image/167388556/large.jpg)



Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on April 29, 2018, 10:51:34 PM
This weekend's shop time was occupied with the port block.  Again I used imperial measurements but needed to retain the metric spacing of the mounting holes for the steam chest.  I started with a piece of 6061 5x2x1 inches and whittled it down to this:

(http://www.pbase.com/kvom/image/167397543/large.jpg)

(http://www.pbase.com/kvom/image/167397537/large.jpg)

Posing with the cylinder:

(http://www.pbase.com/kvom/image/167397532/large.jpg)

I still need to drill the exhaust outlet and tap the mounting holes 8-32.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Gas_mantle on April 29, 2018, 11:27:24 PM
Looks good, a lot bigger than I expected  :)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on April 30, 2018, 12:37:30 AM
The cylinder is coming together very nicely Kirk. Its bigger that I had expected too, should make for a very nice model though.

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on May 01, 2018, 02:05:26 AM
Looks great.  That is an interesting method of creating the ports.  At that size it's going to have quite a bark. :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Jasonb on May 01, 2018, 07:11:49 AM
Hope it will bark loudly as I can't see much point in milling out the nice wide passage and then squeezing all that air/steam through one small hole at the end of the cylinder? I think I would at least have made the cylinder holes the same area as the ones from the ports, easily done my making them a slot about the width of the visible steel.

It's also usual to have a larger exhaust area so you are not using up energy forcing the exhaust out but with just 3 holes from the port you have the same area as the inlets.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 01, 2018, 02:45:03 PM
The exhaust holes are larger than the inlet holes (.155" vs .125").  I didn't want to attempt a deep pocket with a 5/32" endmill on the ports.

I suspect that the bottom inlet port into the cylinder should be enlarged, but I'm also thinking that the the down stroke won't need much pressure at all.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Jasonb on May 01, 2018, 04:57:35 PM
That still sounds very small for a large cylinder. Looking at the Muncaster origianls Jo posted I would say he had the ports and passages the same cross section all the way to the cylinder about 3/16 x 1 and you only have ONE 5/32" hole at the ends of the cylinder, that's less area than a little 3/4" bore Stuart 10V. and only about 10% of Muncasters.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 01, 2018, 10:43:31 PM
On the valid assumption that Jason knows more about this than I, I decided to enlarge the ports, although probably not as much as he recommends.  Going by Julius' SW assembly the piston as drawn has a stroke the entire length of the bore, meaning enlarging along the vertical would be problematic.  If the model turns out to have need of more air, the length of the piston can be reduced allowing further enlargement of the opening. Time will tell.  I suspect Julius didn't do any calculations of air supply issues.

So first I needed to orient the cylinder with the flat horizontal.  This was my method:

(http://www.pbase.com/kvom/image/167405947/large.jpg)

With larger ports machined:

(http://www.pbase.com/kvom/image/167405950/large.jpg)

I decided that to attach the steam chest to the port block, I'd use screws from the back of the flange.  This allows the chest to remain firmly attached to the port block when the cover is removed.  The cover and chest are attached with longer screws using the other 4 holes plus shorter screws for the flange holes that are through tapped.

(http://www.pbase.com/kvom/image/167405952/large.jpg)

(http://www.pbase.com/kvom/image/167405954/large.jpg)

The steam chest is the first metric CNC part I've made.  I exported the DXF from the SW part given metric measurements for all dimensions.  When loaded into my CAM program, the fact that the drawing is metric meant that all generated moved were in mm.  Of course, not having any metric endmills or drills, I had to calculate their diameters, and likewise needed to get used to specifying feeds in mm/min.  The fact of G21 occuring in the g-code file caused my mill control to switch as well.

For edge finding I typically jog down to .001" accuracy, which matches the accuracy of the mill.  However, in metric the .001 jog button changed to .01mm, which is about .004".  SAo now I have to also use the .0025 mm button to get to the same accuracy.  And since my edge finder is imperial (.200), I'm better off finding edges in imperial before switch to metric.

I still need to drill the holes for the valve rod and steam inlet in the chest, along with holes for the mounts.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: john mills on May 01, 2018, 11:19:20 PM
.01mm  = .0004" that shifting of decimal points causes all sorts of problems and can be very dangerous.
i learnt to stick to metric years ago i did one program in imperial but that was because was a bigger complex part

and i didn't want to change it all to metric stored offsets changed i didn't have drawing or cad programs i did lots of profile shapes in 2 and 3d  just a calculator and pencil .with older machines it was safer and less problems
to stick to metric.





Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Tennessee Whiskey on May 01, 2018, 11:59:31 PM
Kirk, sorry for shooting my mouth of on the NAMES thread; guess it was a bad day  :facepalm:. I guess I can see at that size of cylinder a nice pre bored cylinder would make sense. Great build and Iíll be following, even if I donít understand a thing about G this or that.  :popcorn:and  :DrinkPint: in hand

Cletus
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 02, 2018, 01:03:51 AM
I just regard this material like drill rod, already polished and ready to use.   :)

Last jog button under metric is .025 mm or .00098", close to a thou. 
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 03, 2018, 01:00:57 AM
This morning I spent working on the steam chest cover, using some 1/4" brass.  Pretty simple part other than getting the corners of the inside spigot to fit tightly to the chest.

(http://www.pbase.com/kvom/image/167413093/large.jpg)

(http://www.pbase.com/kvom/image/167413095/large.jpg)

In the afternoon made a start on the cylinder cover.  First op was turning the top surface and its spigot.

(http://www.pbase.com/kvom/image/167413097/large.jpg)

After parting off, then the bottom surface and the spigot to fit the cylinder bore.

(http://www.pbase.com/kvom/image/167413099/large.jpg)

Next time in the shop I'll finish the mounting holes.  I was waiting for the post to deliver some 4" aluminum round for making the beam collar, but for some reason moving the package from North Atlanta the final 15 miles takes more than 2 days.   :shrug:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 03, 2018, 09:48:34 PM
Carrying over from yesterday, I got the cylinder cover holes drilled this morning.


(http://www.pbase.com/kvom/image/167419669/large.jpg)


The postman arrived at noon with my delayed piece of 4x1" aluminum round bar.  This will become (hopefully) the bracket that goes around the cylinder below the flange and supports the two longitudinal beams.  The Solidworks rendering of the part:

(http://www.pbase.com/kvom/image/167419673/medium.jpg)

Since I want a good fit around the cylinder, I laid it out as follows on the bar so that the center hole could be accurately bored on the lathe.

(http://www.pbase.com/kvom/image/167419672/large.jpg)

Started with 1/2" and 3/4" drills, then boring bar, with final passes at 5 thou until the cylinder could slide in securely.

(http://www.pbase.com/kvom/image/167419671/large.jpg)

(http://www.pbase.com/kvom/image/167419670/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on May 03, 2018, 09:51:55 PM
That bracket is quite complex, all is looking good! 


 :popcorn: :popcorn: :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 03, 2018, 10:34:16 PM
Pursuant to the idea to use powder coat instead of paint, I talked to my friend who has an offroad shop and does a lot of powder coat on parts.  He has an extra Eastwood gun he'll sell me plus some powder to practice with and use of his oven.  He showed me some aluminum with a powder that made it look like cast iron, so my plan is to do a bit of practice at his shop.  He also said that the powder coat will effective "glue" two parts that are just mated surface to surface quite securely;  if so that will provide a way to fasten the port block to the cylinder.  I'll need to do a test for air tightness.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on May 04, 2018, 09:51:25 PM
Kirk
I was looking at that bracket, realizing there's more detail underneath that I can't see... sure am glad it's you having to make it and not me :ROFL:

You're coming right along with some fine work.  It will be an impressive model when done  :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 05, 2018, 12:41:44 AM
Craig, this is a part that I think would be a challenge on a manual mill.  I spent all day on it today; 90% checking my CAM and workholding, and 10% actually milling.

To hold the 4" round I briefly considered clamping it rightly on the vise (which probably would have been OK), but then decided to mill soft jaws for a more secure hold.

(http://www.pbase.com/kvom/image/167424282/large.jpg)

Next some drilling followed by profiling to 17mm, 2 mm deeper than the finished part.

(http://www.pbase.com/kvom/image/167424284/large.jpg)

Then back to the lathe, where I secured the work with the outside of the jaws in order to turn the part to 17mm.  This was working well until the final facing pass when the work came loose on the jaws.  The aluminum had gotten hot and the hole expanded.  No damage done, but off to the Bridgeport for the last pass with a face mill.

(http://www.pbase.com/kvom/image/167424287/large.jpg)

Finally I needed to hold the part to finish the bottom lugs.  Turned out milling the "arms" unsupported resulted in some whiny chatter, so I had to kludge up some supports.

(http://www.pbase.com/kvom/image/167424289/large.jpg)

That was the last of the shop time.  Still have tapping, drilling, and facing to final dimensions.  Most aren't super critical.

(http://www.pbase.com/kvom/image/167424290/large.jpg)

(http://www.pbase.com/kvom/image/167424292/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on May 05, 2018, 12:44:06 AM
That looks great Kirk. I hope you will take some pictures of your adventures with powder coating too and share them with us.

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 06, 2018, 01:30:45 AM
Spent today drilling and tapping all of the unfinished holes in the cylinder assembly:

(http://www.pbase.com/kvom/image/167429511/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on May 06, 2018, 01:48:27 AM
Looks like the nuke in one of those spy movies!


Very nice!


 :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on May 06, 2018, 02:38:24 AM
 Spectacular work Kirk, this project is really starting to take shape.  :ThumbsUp:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: scc on May 06, 2018, 10:31:22 AM
This is an interesting way of cylinder / valve chest construction, it would suit my metal stocks very well.    Nice progress, thanks for the detailed posting :ThumbsUp:        Terry
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 06, 2018, 11:26:11 PM
Today's part is the cylinder base, which attaches the cylinder to the engine base and also serves as the bottom cylinder cover.  Carved out of a piece of Mic6 aluminum that started as ~ 3.5x3.5x.5".

(http://www.pbase.com/kvom/image/167434381/large.jpg)

The 5-40 holes that attach to the bottom flange are counter sunk.

(http://www.pbase.com/kvom/image/167434382/large.jpg)

With the bottom flange attached.  I'll need to buy shorter screws or shorten the ones I have.

(http://www.pbase.com/kvom/image/167434383/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 08, 2018, 10:31:16 PM
The material for the base showed up Monday, so I spent today on the first ops.  It will be a composite of two pieces of aluminum bar bolted together.  The bottom part is 6061 aluminum, 3/8" thick.  The upper is 3/4" thick.  The actual vertical dimensions are not critical, and this combination gives a total height pretty close to the metric height as drawn.  Both are from stock 4x14".

To hold these in the vise of the CNC mill, I mounted the 12" aluminum jaws and milled a fresh groove 3mm deep.  These jaws got a good workout when building the Joy engine, so now it was time to reverse them and use the bottom.

(http://www.pbase.com/kvom/image/167449193/large.jpg)

The two portions are attached by 6 8-32 screws.  The holes for the bottom section are tapped.  Not wanting to cut into the soft jaws, the outer perimeter was milled only halfway on the lower piece.  Then the upper piece was drilled for 8-32 clearance through holes and the well for the conrod was milled.

(http://www.pbase.com/kvom/image/167449195/large.jpg)

Then the lower section was screwed to the upper to serve as a fixture to complete the lower's outer perimeter.

(http://www.pbase.com/kvom/image/167449198/large.jpg)

That completed the lower section for now.  Since the flywheel extends below the bottom of the base, some sort of plinth will need to be created for the engine to sit on.  So the base may need some additional tapped holes for attaching that.  I'll continue to work on the upper section the next time in the shop.  A few milling ops to finalize the shape and a good number of holes that'll need to be tapped.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 13, 2018, 01:12:25 AM
I had a pretty disastrous last two days in the shop.  First I messed up my offsets in milling the upper half of the base and ruined the part, so I'll have to order another piece of 6061 and start over.  Next I managed to crash the sensor in my Haimer edge finder while using it to test the tram of my mill (finger fart), so that was $70 worth to replace both items plus the time I'd already spent on the base.

So I decided to make a start on some other parts I'd been thinking about how to make.  These "eccentric strap bearing brackets"  support the cross rod to which the cranks for the eccentric and valve arm attach.  Here's Julius' design from Solidworks.

(http://www.pbase.com/kvom/image/167471537/medium.jpg)

My idea is to machine all but the tubular part and then attach the bearing portion later.  As it happens, two of these can fit inside a 1.5" hex rod.  So I turned a spigot in the stock to hold with a 5C collet and collet block.  Then the first op with the block vertical is to mill the outer profile (7/32 endmill), inner pockets (5/32 endmill) and the 5-40 clearance holes.

(http://www.pbase.com/kvom/image/167471534/large.jpg)

Then with the block horizontal, mill the side and front profiles.

(http://www.pbase.com/kvom/image/167471535/large.jpg)

Finally, with the block horizontal, I used a 1/2" endmill to cut the profile for the bearing.

(http://www.pbase.com/kvom/image/167471536/large.jpg)

Now it was time to part off and face the bottoms to proper thickness.  And that's where I discovered my problem.  There's no good surfaces for clamping  in a machinists vise.  After struggling with this for a good while, I decided to loctite some 1/2" rod onto the tops, and see if it will hold securely enough for facing the bottom.  If I have to start over , I'll part off after the first machining op since I'll have flat surfaces for clamping in order to face the bottom.  After that the parts can be screwed to a fixture place for remaining ops.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on May 13, 2018, 01:22:49 AM
Could you silver solder on the rod for the tubular part, maybe leave thay long, and grip there? Especially if the round was turned into some squared bar, so you can grip the square?
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Jasonb on May 13, 2018, 07:15:07 AM
Saw off to leave say 1/8" of the hex then I would have thought you could hold in the mill vice by the end faces as shown in red. Slip a thin packer between vice top and area marked blue so you don't cut into jaws as you mill the bottoms flat.

I'd silver solder the round part on first as one piece to keep things lined up, if you try to do it as two pieces things are bound to move.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on May 14, 2018, 10:52:54 PM
Kirk, I feel your pain.  Every once in a while I buy one of those edge finders with the LED that comes on when it touches.  They work great and are a real boon for my aging, poor eyes.  Unfortunately, tney won't take kindly to being run past center and inevitably, sooner or later, I crank the mill table the wrong way and destroy the edge finder.  Guess I'm stuck with the spring loaded ones.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 15, 2018, 03:28:20 AM
I bought a couple of replacement sensors that arrived today.  We'll see if they survive longer.

An interesting fact is that each new sensor needs to be adjusted to be concentric to the tester.  To do this I clamped my B&S indicator to the mill vise and adjust so that the sensor is centered on the indicator, which is accurate to around 2 tenths according to the dial divisions.  The sensor can be adjusted to about 4 tenths total runout, at least on my CNC mill.

One use that occurred to me is that I can use it to perfectly center my QCTP lathe tools.  Hold the Haimer in my 5C collet chuck on the lathe, move the tool tip underneath the sensor, and use the adjustment screw to zero out the reading.

Back on the topic of the failed bearing bracket, I have come up with a different approach that I think will work around the problems of the first attempt.  I'll post my result when I get back in the shop to test it out.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Stuart on May 15, 2018, 07:46:28 AM
Kirk

Had the same disaster with my Tcshorn taster sniped the ball off the end of the tip same way as you finger trouble  :old:

Yes these are the same you need to recentre it

Please note the word Ďtasterí is not a typo itís the German for tester

Model is looking great

Just finished up a set of the d shaped split basses for the main rod for my beam engine interesting CAM to use a slotting cutter ( looks like a key seat cutter) I had to use cutter comp G41 to get the grove to fit the strap
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 16, 2018, 12:09:15 AM
Completed the first few ops on the new strategy for the brackets:  all 1-piece. 

(http://www.pbase.com/kvom/image/167489586/large.jpg)

This used 1-7/8 hex.  I left 3mm of connective tissue to hold the two parts together until the end, once freed from the hex.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Admiral_dk on May 16, 2018, 11:24:39 AM
You achieve very nice surface finish Kirk - is this down to very good tools (mill etc.) or is it a light finish cut in the code (or both) ?
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 16, 2018, 12:23:06 PM
The outer profiles used a 3/8" 3-flute HSS endmill with 1.5" DOC.  Inner pocket was a 5/32" carbide endmill with same DOC.  Both cutters are relatively new and sharp and are US-made.  I gave up on Chinese/Indian tooling a good while back.  Attending the NAMES show each year is a good chance to stock up on new-old-stock endmills from several vendors.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 16, 2018, 07:53:59 PM
Rest of the ops on these parts were done on the Bridgeport.  First, drill the mounting holes for 5-40.

(http://www.pbase.com/kvom/image/167493974/large.jpg)

Then drill and ream the holes for the shaft (.251" reamer for 1/4 shaft).

(http://www.pbase.com/kvom/image/167493979/large.jpg)

Then after various apps to finish and separate, the two parts:

(http://www.pbase.com/kvom/image/167493980/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 17, 2018, 11:34:36 PM
I received the material for my base do-over and thus far haven't messed up.  Posed with the cylinder to give a sense of scale.  Still many holes to be drilled and tapped.

(http://www.pbase.com/kvom/image/167499517/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on May 18, 2018, 12:06:23 AM
Looking like it will be an impressive engine.


 :popcorn: :popcorn: :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 18, 2018, 11:26:19 PM
Got all the holes drilled in the base, so the only machining left is the angled face between the two levels.  On the drawing it's 35.5 degrees, so since I don't have a 1/2 degree angle block I'll settle for 35.  Using the 25 and 10 blocks together, I positioned the work in the vise.

(http://www.pbase.com/kvom/image/167502795/large.jpg)

Then it was a matter of eyeballing small cuts in both X and Z axes.

(http://www.pbase.com/kvom/image/167502796/large.jpg)

Then an hour to tap all of the 5-40 and 8-32 holes.  Here's a trial fit of some of the parts.

(http://www.pbase.com/kvom/image/167502797/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Tennessee Whiskey on May 18, 2018, 11:46:31 PM
Itís all looking great Kirk. When I see those Lawson boxes in the background, it brings back a lot of memories. My grandparents lived on a farm that adjoined the Lawson plant here in Springbucket back in the sixties. I would ride my bike on their parking lot cause it was a lot smoother than the gravel road that went past their plant to my grandparentí house.  I think they made the ďbullet topĒ trash cans you saw in every service station as a youngster. Actually, now they are quite sought after, especially the ones with the polished lids.  Little aside, but, I am still following the build  :ThumbsUp:

Cletus

Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on May 19, 2018, 01:10:08 AM
I have missed a few days of posts Kirk. Its starting to come together and looks great. Will try to keep up better. :)

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on May 19, 2018, 03:40:20 PM
Everything looks first class Kirk, this project is really moving along. :ThumbsUp:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 21, 2018, 09:42:44 PM
I need to figure the best way to make all the rods that support the beam.  Since they all come is pairs where the dimensions between the cross holes need to be pretty precisely the same, I'll either need some CNC technique or a clever jig.  In the meantime I've ordered some aluminum stock to make the lengthwise support beams.  I'm heading out on a 1-week trip starting Wednesday morning so there will be a gap in any progress.

Today I decided to make the piston and start on the piston rod.  Took a 7" piece of 1/4" drill rod and threaded one end 1/4-28 x 1/2".  Then for the piston I took a chunk of 1-7/8" hex brass on the lathe; faced, drilled 1" deep (#3 drill) and tapped 1/4-28.  The turned down the end to 1.75" round and parted off a 3/4" length.  Now I could screw the brass onto the drill rod, and from then on turn with the rod in a 5C collet chuck.  This ensures that the piston and rod will be concentric.

(http://www.pbase.com/kvom/image/167517958/large.jpg)

Measured the diameter with a mic several times as I turned it down, and finally went to 1.501", where I could just fit it into the cylinder.

(http://www.pbase.com/kvom/image/167517959/large.jpg)

Given that the tube has a honed bore with no taper, I was not surprised that the piston was able to fit smoothly inside end to end.  What was really pleasing was that with the flange and cylinder cover in place, the rod and piston moved smoothly through the cover without any binding.   :cartwheel:

Both the piston and rod are left overlong.  I have to adapt the ends of the piston rod and conrod to fit the v2 split beam.  Julius drew v2 to have spit bearings with wedges and cotters at the beam ends.  I may well content myself with non-split bearings, with the ends threaded onto the rods to allow length adjustment.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on May 22, 2018, 12:30:14 AM
Looking great Kvom! 

Making all those bars the same length between holes is a perfect spot for a jig - drill the holes in one end of each bar, use that hole to screw it to a rectangular block in the mill vise. Move the table over the distance needed, and lock it down. Then drill each part, using the first hole to hold them to the jig (can put another clamp on to hold the bar into a groove to hold it straight).

 :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Jasonb on May 22, 2018, 07:00:39 AM
Not sure why a jig or CNC is really needed to position the holes. The bars can just be held in the mill vice to drill and ream one end , zero the DRO and then move the required distance to the other hole. All other work can be done after that so they are easy to hold weather you decide to start with flat or round stock. Any jig will have small clearances which could cause differences but holding the actual part wont.Julius has put simple closed ends on them so it is not as though you have got split bearings on the ends of them all.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 22, 2018, 12:33:57 PM
The fixed stays are all of this form (see photo).  The round ends will have a 1/2" diameter with through hole 1/4".  The connecting shaft will be 3/8".  If I assume that each will be assembled from 3 separate parts then a jig of some sort is needed to hold the ends apart the appropriate distances.  There are 3 pairs needed with different lengths.  The cross holes must be parallel of course.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Jasonb on May 22, 2018, 01:22:30 PM
If you are going for built up then yes, I was assuming made from one piece like the drawings show similar to the closed end ones in this pic

(http://img.photobucket.com/albums/v156/jasonballamy/Engineering/EastonandAnderson/IMAG1265_zpsf75ce7af.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 22, 2018, 03:04:20 PM
There's a Solidworks image attached to the post. 

I suppose these could be made from bar stock with a form tool for the ends.  I don't own a ball turner, which would be easier, or else graduated cuts with a parting tool (my previous tries at this have not yielded very good spheres.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Jasonb on May 22, 2018, 03:13:32 PM
You just need a rounded end tool in the lathe to do the fillet where the rod meets the ends, round over the end with file and buttons or on the rotary table and finish off with a round needle file to blend the two together
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 22, 2018, 03:22:30 PM
When I got the CNC mill my rotary table went away.  Still, something to think about if other methods are unsatisfactory.

My little CNC lathe might work well for 1-piece solution in aluminum or brass, but probably not in steel.  I have a large amount of 1/2" square and hex brass to play around with.  I doubt brass would look appropriate for this model, but powdercoat would solve that.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 23, 2018, 12:12:07 AM
One last job before taking off to Belize and Guatemala for a week.  The two halves of the split beam.  Since Julius both magnified the V2 drawing and also made all the hole spacing integral mm, I didn't think it safe to just scale the V2 drawing.  So I mainly kept the V1 hole spacing and added the pockets and bosses, thus insuring (hopefully) that the engine will turn over without binding from the support rods.  I still need some cleanup of the edges when I return.

(http://www.pbase.com/kvom/image/167524684/large.jpg)


Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on June 01, 2018, 10:13:47 PM
Back from Central America and back to work on the grasshopper.  Managed to get the first op (top profile) machined for the horizontal beams.  Still 3-4 ops left on these parts.

(http://www.pbase.com/kvom/image/167579470/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on June 03, 2018, 11:56:10 PM
After profiling, the beams need various ops to bring to completion.  Here's one that I came up with to machine the space at the end.

(http://www.pbase.com/kvom/image/167590460/large.jpg)

Almost done here:  I spot drilled the places for the side mount holes to be able to check the fit before through drilling.

(http://www.pbase.com/kvom/image/167590461/large.jpg)

The holes did seem to line up after a made a temporary column, so I drilled and bolted it up.

(http://www.pbase.com/kvom/image/167590462/large.jpg)

Measurement showed that the right end is about 1mm low, but since the column is screwed to the base with a long 8-32 set screw it's easy to adjust the height.

Julius shows some fancy turning as the top and bottom of the column along with a slight taper in the shaft, so I'll have to see what can be done there.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on June 04, 2018, 01:06:00 AM
Those columns and beams are looking great!

 :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on June 12, 2018, 09:41:01 PM
Back at it in a small way.  Started on the main bearing block.  This is the bottom portion.  Started with a piece of 6061 2x1x1" and used a 3/8" carbide roughing mill to profile leaving .3mm clearance.

(http://www.pbase.com/kvom/image/167640107/large.jpg)

Then used a .25" endmill leaving a .2mm clearance.  This is so that a final profile with the top portion attached will match on both sides.  After profiling and drilling the 5-40 mounting holes, the bottom was machined to a total height of 25mm.

Shown in place on the frame.

(http://www.pbase.com/kvom/image/167640108/large.jpg)

Next time I'll start the top section.  Moving along slowly but I imagine it'll be done before Zee's engine.  Cletus' I'm not sure about.   :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: zeeprogrammer on June 12, 2018, 10:47:33 PM
Moving along slowly but I imagine it'll be done before Zee's engine.

 :cussing:

Replace the word 'imagine' with 'know' and I believe you'd be spot on.  :facepalm2:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on June 13, 2018, 01:20:52 AM
More excellent progress Kirk. Gonna  be a fine looking grasshopper for sure!!

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on June 13, 2018, 10:13:49 PM
For the top part of the bearing block, I started with a 2x1x.75" piece of 6061 and profiled. 

(http://www.pbase.com/kvom/image/167643568/large.jpg)

Then on the Bridgeport I machined off the unwanted part and drilled the clearance holes for 8-32 screws.

(http://www.pbase.com/kvom/image/167643569/large.jpg)

Then did final profiles with the two halves attached.

(http://www.pbase.com/kvom/image/167643564/large.jpg)

Next, bored and reamed for a 3/4" hole for the bearing.

(http://www.pbase.com/kvom/image/167643565/large.jpg)

(http://www.pbase.com/kvom/image/167643566/large.jpg)

The off to the lathe to turn the bearing itself.  I couldn't find any piece of 5/8" drill rod, which if what I'd intended to use for the crankshaft, so I just predrilled it 1/2".  I do have a piece of chrome steel that measures .621";  if it turns out to be machinable I'll just bore the bearing to fit.  But in the interim, this is what we have.

(http://www.pbase.com/kvom/image/167643567/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on June 14, 2018, 09:14:21 PM
Still folliwing along Kirk.  :popcorn:
This engine is starting to take shape.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on June 15, 2018, 01:18:11 AM
I decided to order some 5/8" drill rod for the crankshaft, so while waiting for MSC to deliver I turned my attention to the eccentric.  Julius drew the strap to have a thin bronze inner bearing, but machining that ring means losing the interior as chips.  So I plan to make the eccentric itself from 660 bronze (I have a 2" diameter piece at hand) and the strap from aluminum.

Extracting the side profile from the SW file allowed seeing that the two halves together fit within a 3" circle with enough space between for a 3/8" endmill to pass.  I've had a piece of 3" diameter rod for ages, and slicing off a piece to order means not needed to worry about how thick I'd need to have on hand if I were going to use a bar or sheet.  In this case I had a piece of machined round that was an aborted part for another long ago project, so it was on to the mill to machine the profiles.  I cut them 10mm deep although the strap itself will end up 7mm thick.

(http://www.pbase.com/kvom/image/167647866/large.jpg)

Then I cut them loose by parting on the lathe (actually needed to hacksaw the last 1/4"), then face milled both sides at the Bridgeport.

(http://www.pbase.com/kvom/image/167647867/large.jpg)

I started late in the day, so this was as far as I got today.   The rest is pretty similar to the process for the bearing block.  Drill and tap to screw the two halves together, then drill/tap for the eccentric rod and cut out the center hold.  The the strap can be used when machining the matching groove in the eccentric itself.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on June 18, 2018, 10:39:38 PM
Last two shop sessions continued with the eccentric.  Here's the two halves of the strap drilled/tapped.  5-40 screws for closure, 8-32 for the rod.

(http://www.pbase.com/kvom/image/167668586/large.jpg)

The next op was to interpolate mill a 40mm hole in the center of the strap.

(http://www.pbase.com/kvom/image/167668587/large.jpg)

Now the strap can be used to mill the groove in the eccentric itself.  I started with some 2" bronze bar and turned down to 44mm.

(http://www.pbase.com/kvom/image/167668588/large.jpg)

The groove was cut with parting tools carefully creeping up on 40mm using the strap to check for fit.

(http://www.pbase.com/kvom/image/167668589/large.jpg)

Next op was to mill the boss for the eccentric hub.  I cut a strip of shim stock to fit in the groove and then tightened the strap on it so that it couldn't turn.  The bore for the crankshaft was milled undersize and will be bored to size on the lathe.  As with the main bearing, my small micro carbide boring bar is too short to go all the way through.  I have ordered one with a .5" shank and 2" reach that I'll use for both.

(http://www.pbase.com/kvom/image/167668590/large.jpg)

Also TBD are tapped holes for grub screws to attach the eccentric to the crankshaft.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: zeeprogrammer on June 19, 2018, 12:59:54 AM
Looking good.  :ThumbsUp:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Tennessee Whiskey on June 19, 2018, 01:04:17 AM
I like grooving the eccentric rather than the strap, lot more bearing surface.

Cletus
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on June 19, 2018, 02:27:46 AM
And a lot easier too.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on June 19, 2018, 10:34:15 PM
After considering different ways to make the various links for this engine, I decided to try to make each from a single piece of stock rather than fabricating.  The main advantage, as I see it, is that the links are to be made in pairs and being able to predrill their mounting holes means that each member of the pair has the same effective length.

The width of the heads is 12mm on the majority of the them, so using 1/2" square bar makes sense.  And I happen to have a 6' stick of 1/2" brass bar, so my intention will be to make them from brass.  Normally steel would look more authentic, but I'll be powder coating these so the yellow color won't be an issue. 

The first to be attempted will be one of the swinging links that attach to the end of the beam.  The holes are 102mm apart, and the length of stock needed is 118mm.  After cutting off a piece and trimming to length, I used a center drill in each end.  That square collet I picked up at CF some years back came in useful.

(http://www.pbase.com/kvom/image/167676016/large.jpg)

Then off to the CNC mill to drill the holes and profile the link.  By leaving 1/8" of stock at the bottom, I expect to be able to hold one end still in the 5C collet.

(http://www.pbase.com/kvom/image/167676017/large.jpg)

That hope proved true (otherwise I'd need to turn a dead center and use a lathe dog.  Once mounted, I used a parting too tool make space for a turning tool.

(http://www.pbase.com/kvom/image/167676018/large.jpg)

After some time at the lathe I arrived at this.  It was necessary to reverse the piece in order to turn both ends.  The hold in the collet isn't exact so there was some runout once I'd reversed it.  For the future parts I'd going to increase the head diameter to 1/2" so that the collet can use all 4 sides to center the work.  In any case, I was able to use the parting blade as a turning tool to make the diameter consistent.

(http://www.pbase.com/kvom/image/167676019/large.jpg)

Next it was on to the Bridgeport to take 1/8" off both sides bringing the thickness to 1/4".

(http://www.pbase.com/kvom/image/167676020/large.jpg)

At this point I can hold the shaft with the jaws on my regular chuck, which will allow me to remove the center drill portion and possible taper the intersection of the heads and shaft.

 
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Gas_mantle on June 19, 2018, 10:48:29 PM
Looking good  :ThumbsUp: :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on June 21, 2018, 08:17:08 PM
The new longer boring bar arrived by post today, so I was able to bore both the main bearing and eccentric to fit the 5/8" crankshaft.

(http://www.pbase.com/kvom/image/167684523/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on June 21, 2018, 10:55:56 PM
Nice job Kirk, looks great.  It's interesting to see how others address things you've done yourself.  No single right way, just many ways to achieve the same result.  Who knows, sometime in the future something may prevent me from using a method I've used in the past and one of these ways you've shown here will be the solution I need. Thanks!
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on June 22, 2018, 09:58:32 PM
Today I spent most of the afternoon making these little "stay mounts".  These screw onto the top of the horizontal beam and connect to the middle stays.  The holes in the beams will be located once the stays are all in place.

(http://www.pbase.com/kvom/image/167691618/large.jpg)

Quite a few ops needed on these between the CNC and Bridgeport.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: RMO on June 22, 2018, 10:57:03 PM
Just read through the build log, lots of fun work there.  Thanks for sharing.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on June 26, 2018, 09:47:23 PM
I completed the mill operations for all the rest of the stays, so next it's needed to turn the shafts.    I wanted to turn these between centers since it's difficult to hold the ends centered in the lathe chuck.  Turning between centers requires a center to be turned and left mounted in the lathe, and as well you need a lathe dog to force the work to turn when mounted.  After some deliberation, I came up with the following.

First, a scrap piece of 1.5" aluminum rod was turned down to provide the center, and a 1/4" hole drilled to become part of the dog.

(http://www.pbase.com/kvom/image/167715370/large.jpg)

With the piece mounted and the compound turned to 30 degrees, the center could be turned.

(http://www.pbase.com/kvom/image/167715366/large.jpg)

The rest of the dog consists of a short piece of 3/8" brass rod with a 1/4" hole along the axis and another 1/4" cross hole.  Testing for fit:

(http://www.pbase.com/kvom/image/167715367/large.jpg)

Once the lengths of the two 1/4" rods were determined, they were loctited in the center and the dog respectively.  The stays could then be mounted and turned.

(http://www.pbase.com/kvom/image/167715368/large.jpg)

(http://www.pbase.com/kvom/image/167715369/large.jpg)

Title: Re: Muncaster Grasshopper - Work in Progress
Post by: 10KPete on June 26, 2018, 11:21:27 PM
Very clever!! I love that set-up, just need to remember it...

Pete
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on June 26, 2018, 11:23:42 PM
Some very nice progress Kirk!! I look forward to your updates.

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: zeeprogrammer on June 27, 2018, 12:52:37 AM
Following along Kirk.  :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 03, 2018, 12:46:55 AM
After a lot of time standing at the lathe, I completed all 8 stays.  Here are the 6 nearest the cylinder in their approximate positions.

(http://www.pbase.com/kvom/image/167742170/large.jpg)

Because the vertical stays are relatively unrigid, they must be braced by the diagonal fixed stays, and for this to happen the brackets at the bottom must be screwed to the tops of the rails.  The brackets must be positioned so that the bottom cross shaft is orthogonal to the long axis of the engine, and hence force the top cross shaft to be as well.  Then the middle stays that attach to the beam will be able to swing smoothly as the beam moves.

This setup allowed me to determine the position of the brackets resulting in a rigid structure.  I used a transfer punch to mark one of the four holes needed to attach the brackets.  Then it was off to the Bridgeport with the stays removed but the rest of the assembly still in the small vise.  This allowed me to locate the punch mark for the first hole and then to locate the others to ensure that the holes on each side form a rectangle.  I spot drilled these points, and then removed the beams to drill and tap 5-40. 

(http://www.pbase.com/kvom/image/167748786/large.jpg)

When reassembled we have this.

(http://www.pbase.com/kvom/image/167748787/large.jpg)

To further address alignment I need to turn my attention to the crank and conrod, plus finishing the piston rod end.  Then the beam itself can be assembled and mounted.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on July 03, 2018, 12:50:47 AM
Complex set of bits to get all right, very nice!


 :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on July 03, 2018, 12:54:48 AM
Tedious work but a beautiful result Kirk. And the pictures, as always, are excellent too.

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Dave Otto on July 03, 2018, 01:02:42 AM
They look very nice Kirk!

Dave
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on July 03, 2018, 02:41:09 AM
Still following along Kirk, this project is really starting to shape up!   :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 03, 2018, 08:17:40 PM
Very cranky today so to speak.  Attacked the crank today starting with some ground low-carbon steel bar 1.5x.5x2.5".  Fairly vanilla CNC ops all using one 1/4" carbide endmill do do both profiles and holes.  Larger hole is .626" to fit the crankshaft, and smaller is 5/16", the closest to the 8mm in the drawing.  Finishing the outer profile required making some soft jaws around the two bosses.

(http://www.pbase.com/kvom/image/167752882/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 07, 2018, 03:32:46 AM
Fitting the conrod to the crank so that it's centered on the long axis requires a spacer on the crank pin that is to be determined when the time comes.  And since I don't have a flywheel yet the diameter of the crankshaft through the flywheel is unknown.  For these reasons I have a temporary crankshaft and crank pin.  To fix the crank on the crankshaft is a temporary set screw that will be replaced by a pin in the final assembly.  The crank pin is a length of 5/32" drill rod that is close to the 8mm specified by Julius.

(http://www.pbase.com/kvom/image/167771113/large.jpg)

As drawn in V1, the crank pin and end of the conrod could not actually be built.  Solidworks makes it easy to move one piece of material through another, but physics is not cooperating.  So I have designed a simple rod end that will be used on both ends of the conrod and on the end of the piston rod.  The first stage in making these is cutting 3 sets of profiles from a single piece of 1.5x.5x4.6" steel bar.

(http://www.pbase.com/kvom/image/167771114/large.jpg)

They will be 10mm thick, and with 12mm bearings installed will clear the 14mm separation of the two halves of the beam.  I machined the profiles 11mm deep to accommodate later machining once the halves are joined.  Next the parts are cut free on the bandsaw.

(http://www.pbase.com/kvom/image/167771115/large.jpg)

And then the remaining waste stock us milled on the manual mill.

(http://www.pbase.com/kvom/image/167771116/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 07, 2018, 11:13:29 PM
Continuing with the rod ends, I set the vise stop and DRO in order to do all of the drilling and tapping to connect the halves of each of the three pairs.  Just had to remember to keep the ground side against the fixed jaw.

(http://www.pbase.com/kvom/image/167774549/large.jpg)

After a bit of work, I had these:

(http://www.pbase.com/kvom/image/167774550/large.jpg)

Then drilled and reamed the conjoined pairs .499".

(http://www.pbase.com/kvom/image/167774551/large.jpg)

Then I could clamp each firmly onto a piece of 1/2" brass rod and face turn to bring the thickness to 10mm.

(http://www.pbase.com/kvom/image/167774552/large.jpg)

Then I made the first two bearings from some .77" 660 bronze rod.  I'll finish the third bearing next time out and start to think about the conrod,

(http://www.pbase.com/kvom/image/167774548/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 09, 2018, 11:16:21 PM
Short work session today.  First off was to "fabricate" a temporary conrod that I'll use to verify the length and spacing before making the real thing.  The temporary rod is just some 1/4-20 threaded rod onto which 2 rod ends are screwed.  The plans call for a 205mm spacing between the bearing centers, and the rod I started with was a good deal longer.  So with the following "set up":

(http://www.pbase.com/kvom/image/167785999/large.jpg)

I positioned the 5/16 drill bit over one end until it could enter the bearing, zeroed the DRO, and moved to the other end to do the same.  The DRO reading:

(http://www.pbase.com/kvom/image/167786000/large.jpg)

So I needed to part off 81mm from the rod.  After doing so and repeating the measurement:

(http://www.pbase.com/kvom/image/167786001/large.jpg)

The rest of the afternoon was machining 3 spacers from 1/4" drill rod, each 14mm long and tapped 5-40 in both ends.  This job was a bit more tedious than it might have been as these are for spacing the two halves of the beam, and I wanted them to be as close to 14mm as I could.

(http://www.pbase.com/kvom/image/167786002/large.jpg)

As you can see, I'll need some more small screws from AME for this part.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 10, 2018, 11:42:37 PM
Proceeding further with the beam, I need to attach it at 5 separate points:  piston rod, conrod,  middle stays, end stays, and the pump.  Each of these has 1/4" holes drilled through both sides of the beam.  To make the connections, I decided to use 5/16" rod cut in 14mm lengths for the center section, each drilled and reamed .251".  Through these will be passed 1/4" rod.
 Doing it this way makes it easier to hold the center section length more precisely, and is much easier than turning each connection from a single piece of drill rod.  Once the lengths of the 1/4" rod are fixed, the two pieces will be loctited. Note that the 5/16" diameter matches that of the rod end bearings, which were reamed .001" over.

(http://www.pbase.com/kvom/image/167791628/large.jpg)

After taking the previous picture and verifying that turning the crank resulted in motion that looked pretty good (i.e., the holes for the piston rod end seemed to move straight up and down, I decided to prolong the shop session by cutting the piston rod to length and threading the end.  After attaching the rod end to the rod and the beam, I was pleased to see that turning the crank caused the piston to move up and down in the cylinder without too much effort (little sticky at the top), and that the piston travel was nearly perfect (the edge in each direction barely touch the bottom of the steam ports.  Given that the temporary conrod isn't precisely straight, I'm encouraged  by the motion.

(http://www.pbase.com/kvom/image/167791627/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on July 10, 2018, 11:58:04 PM
Nice!    :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: zeeprogrammer on July 11, 2018, 12:11:32 AM
Wow! Not sure how I miss some posts but I sure missed the last few.

Looks great!  :ThumbsUp:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on July 11, 2018, 02:02:16 AM
Yowza !   :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Jasonb on July 11, 2018, 07:09:56 AM
Coming together well. Probably best to check for tightness with the top cylinder cover in place as without it as in the photo the piston rod can lean sideways if the linkage lengths are out.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 18, 2018, 10:10:22 PM
I remade both the piston rod and the the conrod using thread milling to ensure straight threads.  Upon reassembly the middle stays no longer match up with their connections to the beam.   >:(

I need to remeasure everything to see what might have happened.  Length of piston rod won't matter, so length of conrod is a suspect.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Jasonb on July 19, 2018, 07:22:44 AM
With threaded ends to the rods you are only ever going to be able to set the rod length to within half a thread pitch if you are going to keep the ends lined up. May be better to put a spigot on the end of the shaft, drill the end and then loctite/pin together. Trim the spigots shoulder to set exact length.

Also any slight bend in your drill bit or runout in the chuck that you are using in your photos above to set lengthwill throw the measurement off, try a short pin in a collet.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Brian Rupnow on July 19, 2018, 03:27:40 PM
I like that jointed mechanism on the end of the beam to keep the piston rod travelling straight up and down. Sooner or later I am going to build a mechanism like that just to see it work. You are doing a great job.---Brian
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 20, 2018, 12:48:24 AM
Turns out that the collar around the cylinder had slipped, causing the mismatch between the stays and beam.  One issue I've been seeing is that the stays can move around on their shafts causing binding.  The solution is to make spacers that keep the ends of the stays in place.  Rather than drill out 3/8" rod, I ordered some 3/8" steel tube from McMaster that I l'll ream .251.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 24, 2018, 11:20:45 PM
I finally got all the spacers made and put it all back together.  If I operate by pulling and pushing the piston rod it's stiff but not binding.  However at TDC and BDC of the crank, I have to push the crank past in order to continue.  It's very difficult to drive via the crankshaft, but when one considers the lever arms of the two options it's easy to see why.

I still need a couple of spacers to center the conrod on the crank pin, and need to fasten the crank to the crankshaft more securely than just a single grub screw if I want to try to run it in using the crankshaft as input.

(http://www.pbase.com/kvom/image/167860857/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on July 24, 2018, 11:30:07 PM
Its not bottoming out the piston at tdc and bdc? I have had ones where I needed to take a smidge of thickness off the piston.


Looking great!
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 25, 2018, 12:22:53 AM
Travel of the piston is good. The edges end up right at the steam port margins.  I adjusted bottom position via the piston rod and top position via the conrod.  By TDC/BDC I was referring to when the conrod and crank web are parallel.
 
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 27, 2018, 09:19:58 PM
Today I attacked to eccentric rod.  Starting with some .5" diameter drill rod, I drilled and tapped a 10-32 hole about .3" deep.  This will form the "head" of the eccentric.  Next with some 3/16" drill rod cut to length, I thread milled 10-32 threads on one end and 8-32 threads on the other.  That was because I'd tapped the eccentric strap 8-32 thinking I use 1/4" rod here and join it to the strap with threaded rod. 

(http://www.pbase.com/kvom/image/167877761/large.jpg)

An advantage of thread milling here vs. a die is that I didn't need to turn down the 8-32 end.  I basically used the 10-32 g-code and added a couple of more passes to reach the minor diameter.

Next I drilled and reamed the head .1885" with the rod in place.

(http://www.pbase.com/kvom/image/167877757/large.jpg)

With the pieces assembled:

(http://www.pbase.com/kvom/image/167877759/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on July 27, 2018, 10:10:54 PM
Nicely done!   :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 31, 2018, 09:36:51 PM
This edition was spread over several days because of life getting in the way.

The motion of the eccentric is transmitted by a pair of rockers that pivot on a shaft at the end of the engine.  The rockers in turn push onto assemblies that move the valve up and down.  The first step in making the rockers was to profile them in some 1/4" Mic6 plate.

(http://www.pbase.com/kvom/image/167896468/large.jpg)

Then, using a technique (supposedly) learned from Terry McHugh, I filled them up with Darvon gel epoxy and let it cure overnight.

(http://www.pbase.com/kvom/image/167896469/large.jpg)

A preliminary measurement shows that the lifting ends of the rocker have a vertical travel of ~11.5mm, while the valve travel is 9mm.  Since the rocker arms are fixed length, the only way to adjust the travel is changing the length of the eccentric rod.

I looked a bit further into how the valve mechanism works.  The way Julius drew the valve and valve rod together there's no way it can be inserted into the steam chest.  I have redrawn the valve and separated the valve rod from it, although in doing so I had to reduce the depth of the valve's cavity by half.

The next morning I took off the bottom stock with a face mill.

(http://www.pbase.com/kvom/image/167896470/large.jpg)

At this point I went astray.  Supposedly heating to 300F will allow the parts to be removed from the epoxy while still hot.  I heated them to 400F for too long, which baked the plastic firmly to the parts.  The only option now was to burn off as much as possible with a torch and try to sand or file off the reside.  While this yielded usable parts, I intend to remake these.  Terry says he just fills the troughs with epoxy using a disposable syringe, so I've got an eBay order in for some of these.

(http://www.pbase.com/kvom/image/167896471/large.jpg)

To connect the eccentric rod to the first rocker one needs a short length of drill rod threaded on both ends 8-32.

(http://www.pbase.com/kvom/image/167896472/large.jpg)

The setup wit preliminary assembly.

(http://www.pbase.com/kvom/image/167896467/large.jpg)

Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Tennessee Whiskey on July 31, 2018, 10:26:01 PM
I am following along with you  :popcorn:. I hope that was some Devcon gel and not Darvon gel: that Darvon is a great pain reliever.

Whiskey
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on July 31, 2018, 10:40:35 PM
I probably need both.  Devcon it is.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on July 31, 2018, 10:43:21 PM
Whatever you used Kirk, the results look good  ;)

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on August 05, 2018, 11:10:54 PM
I have been struggling trying to figure the best way to attach the port block to the cylinder.  Relying on a layer of powder coat as both adhesive and air enclosure seems risky, so I think a thin layer of JB Weld is the way to go.  I did an experiment on some test pieces, and got an airtight seal.

To mate the two parts while the epoxy cures I'll use two .062" locating pins.  By drawing up the cross section of the cylinder, I was able to see that at the position of the pins the hole could be up to .226" deep before it would intersect the inner wall.  I drilled the two holes a conservative .150" deep.

(http://www.pbase.com/kvom/image/167925416/large.jpg)

And the corresponding holes in the port block.

(http://www.pbase.com/kvom/image/167925417/large.jpg)

Did a few other things for which I didn't take pics, so I'll save those for later.

The first actual part to be powder coated is the steam chest cover.  I'm debating using the red as an accent color, so this is a test part.

(http://www.pbase.com/kvom/image/167925418/large.jpg)

The red was brighter when I tested on aluminum, but here it's over sprayed onto the cast iron with the material being brass.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: zeeprogrammer on August 06, 2018, 12:10:27 AM
 :popcorn:

Your powder coating learning and experimentation is very interesting.
Probably not something I can (I mean, would) do given my shop constraints. (Similar to the fact that I will never do welding.)

But none-the-less interesting to learn about.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on August 06, 2018, 12:32:06 AM
Powder coating is both easier and cheaper than welding.  Easier than painting in some respects.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on August 06, 2018, 12:57:10 AM
For JB-Welding on the test blocks, did you need to rough up the surfaces to get a good bond? I've used it for fillets and things, not for something holding pressure, any tips?
 :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on August 06, 2018, 01:31:03 AM
I am really liking the powder coating experiments as well Kirk. It just seems more durable than paint when done properly. Of course the engine is looking fine too!!

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on August 06, 2018, 11:55:15 AM
For the test pieces I did use a bit of 180 sandpaper before applying the JB.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on August 07, 2018, 12:11:25 AM
I'm going to start powder coating parts, esp, the bottom-most ones so as to not have to disassemble everything later.  In addition, I need to get the cylinder, its flanges, and the port block bonded permanently.  Before the top flange can be permanently attached, I need to powder coat all parts of the assembly, and as well the beam collar needs to go on as it can't be removed afterwards.

First stage is to loctite the bottom flange to the cylinder.  Everything in the engine depends on alignment along the centerline.  Since the cylinder mounting plate is made square to the base, I use that to align the port block face as shown here.

(http://www.pbase.com/kvom/image/167931142/large.jpg)

Once cured, the loctite should withstand the 400F temp needed for powder coating.

On another note, I whipped up a piece of scrap aluminum and used it to clamp the base to this sine table (7/16 threaded holes in a 1.25" square pattern.  I bought this table years ago quite cheaply but have never used it until now.  The table will serve two purposes.  One is to clear vertical space for a flywheel before the actual sub-base is built.  The second is to allow  The crankshaft to be chucked in lathe jaws for some running in without needing to shim the base.

(http://www.pbase.com/kvom/image/167931141/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on August 19, 2018, 01:21:06 AM
I haven't posted for a while thanks to some computer issues, but have done some work on the engine.  Here's some parts after powder coating.  I have subsequent to this pic glued up the post block to the cylinder using JB Weld, and then the top flange with 620 loctite.  I attached the steam chest and its cover, and then blocked the top of the cylinder before applying air.  No major air leaks seen around the joints. 

(http://www.pbase.com/kvom/image/167991109/large.jpg)

Today's project was machining the valve.  I used Julius' overall dimensions but went with the cross slots and nut for retaining the valve rod.  First op was facing some 2" bronze rod on the lathe.  Turning down the diameter a bit was to provide a bit of extra relief to the endmill in succeeding ops.  The spotting drill dimple in the center was to aid in centering on the mill.

(http://www.pbase.com/kvom/image/167991110/large.jpg)

Given my owning a cutoff D1-3 spindle nose that matches my lathe, I can move lathe chucks with stock attached to the mill.  Then use a wobbler center finder to zero on the dimple.

(http://www.pbase.com/kvom/image/167991111/large.jpg)

Then machined the valve's outer profile and the 3/16" slots:

(http://www.pbase.com/kvom/image/167991105/large.jpg)

After returning the chuck to the lathe, I parted off the valve and moved it to the manual mill for removing the parted material and taking to the proper dimension.

(http://www.pbase.com/kvom/image/167991106/large.jpg)

Then back to the CNC mill to machine the inner pocket using a 5/32" endmill.

(http://www.pbase.com/kvom/image/167991107/large.jpg)

Finished part:

(http://www.pbase.com/kvom/image/167991108/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on August 19, 2018, 01:40:17 AM
Beautiful!


 :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on August 21, 2018, 09:56:44 PM
First project of the day was making the valve rod.  3/16" drill rod 3" long, with 1/4" of 8-32 thread on one end and 3/4" of 10-32 thread on the other.  Then the valve nut from some 1/4" square brass rod machined down to fit the 4mm cross slot.

(http://www.pbase.com/kvom/image/168004643/large.jpg)

Then finished drilling/tapping the steam chest.  1/16-27 NPT air supply hold for the bottom of the chest and provision from the gland at the top.  The gland mounting holes are tapped 5-40.  The gland itself is a project for next time.

(http://www.pbase.com/kvom/image/168004644/large.jpg)

Beauty shot of the assembly.

(http://www.pbase.com/kvom/image/168004645/large.jpg)

After the last pic I powder coated the outer faces of the steam chest to match the rest of the cylinder.  The front and rear faces were left uncoated to facilitate a good seal to the port block and cover.


Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on August 21, 2018, 10:06:08 PM
Beauty indeed!
 :popcorn: :popcorn: :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: zeeprogrammer on August 21, 2018, 10:31:46 PM
Still watching and  :popcorn:. Looking good!
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on August 22, 2018, 02:16:16 PM
Good to see more progress on this one Kirk. The parts are looking great.

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on August 22, 2018, 09:12:17 PM
Today's project was making the valve gland.  The outer profile fits within a 1" circle, so chuck some 1" brass rod in the lathe and carefully turn a 6mm spigot that just fits the matching 3/8" pocket in the steam chest.

(http://www.pbase.com/kvom/image/168009726/large.jpg)

Then drill and ream the center 3/16" rod hole 1 thou over before moving the chuck to the  CNC mill to machine the oval profile and spot drill the mounting 5-40 clearance holes (these needed to be drilled on the manual mill because of Z space)/

(http://www.pbase.com/kvom/image/168009727/large.jpg)

Then part off:

(http://www.pbase.com/kvom/image/168009728/large.jpg)

Finished part:

(http://www.pbase.com/kvom/image/168009729/large.jpg)

And the moment of truth seeing that with the gland mounted on the steam chest the valve rod slides smoothly.

(http://www.pbase.com/kvom/image/168009725/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on August 22, 2018, 10:57:27 PM
Always a good feeling when things fit (and slide) as they should. Nice looking gland!!

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on August 24, 2018, 12:55:34 AM
Today I fabricated the gland for the piston rod.  Pretty much the same as for the valve gland except the outer profile is round;  this meant it could all be done on the lathe and manual mill from 1" round brass bar.

Before turning the spigot, it was necessary to first mill the corresponding hole in the top cylinder cover, which I had neglected to do when the cover was turned.  Since I wanted it to be quite precisely centered over the bore, I used the cylinder as a fixture.  After ensuring the cylinder was vertical, I zeroed the Bridgeport's DROs using the center finder:

(http://www.pbase.com/kvom/image/168014150/large.jpg)

Then I used a 25/64" endmill (obtained in a collection buy) to mill 7mm deep. 

(http://www.pbase.com/kvom/image/168014152/large.jpg)

This resulted in more chatter than I liked, so I chucked it in the lathe to make a skim cut of the sides with a micro boring bar.

I was then able to assemble all the components of the cylinder to test for operation on air.

(http://www.pbase.com/kvom/image/168014153/large.jpg.)

Moving the valve rod with air attached moved the piston up and down quite briskly.  I found almost no air leakage around the steam chest or the glands, but I did feel air leaking around the bottom.   :headscratch:

Inspection showed that the bottom flange had opened a crack where it mates to the cylinder body (via loctite).  This is a bit worrisome as detaching it could pose a problem (I don't want to apply high heat to break the rest of the loctite bond.  By clamping the crack disappears, so I'm thinking to disassemble and apply a new layer of powder coat in the area to seal it after applying more loctite into the opening.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on September 02, 2018, 11:20:44 PM
I had assembled all of the necessary parts except the valve lifters to see how well the entire set of mechanics work.  There is something of a dead spot when turning the crankshaft at the topmost part where turning it in either direction over about 15 degrees yields an imperceptible motion of the beam.  I doubt that's cause of alarm.

When I applied air, moving the valve rod caused no resulting movements of the piston rod.  Examination shows that a crack had developed in the juncture of the port block and cylinder bonded by JB Weld allowing all the air to escape.  I did a partial disassembly to free the cylinder and pried the port   block free.  Seems that the JBW adhered just fine with the aluminum port block and not at all with th steel cylinder.   :headscratch:

The fact that I did a second powder coat of the assembly may be the reason, although the powder coat temp is 400F and JBW is supposed to withstand 700F.

I am going to remake the port block with a few improvements and try again, this time with Loctite.

Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on September 11, 2018, 12:32:11 AM
Some catching up on this thread.

I decided to remake the port block, and this time I didn't let the inner air channel be open at the ends.  I also sized the block so that it is a tight fit between the two cylinder flanges.

(http://www.pbase.com/kvom/image/168100872/large.jpg)

After powder coat I used Loctite instead of JBW to seal the block to the cylinder.  Reassembled, the engine mechanism turns pretty well using a 5C collet block to grip the end of the crankshaft in lieu of a flywheel.

(http://www.pbase.com/kvom/image/168100870/large.jpg)

That was last week.  Today I started on the valve "lifters".  I previous tried to make them from 1/2" square brass, but machining them to thickness resulting in banana shape.  So this time it's Mic6 aluminum.

(http://www.pbase.com/kvom/image/168100871/large.jpg)

I now need to thread some 3/16" rod to connect the lifters to the valve assembly and eccentric levers.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: zeeprogrammer on September 11, 2018, 01:13:11 AM
Some catching up on this thread.

What? Going to take a while? Slowing down a bit?   :lolb:
Just a  :stickpoke: at someone who comments on my speed.  :lolb:
Speed doesn't matter.

It's looking good kvom. I'm following along and learning things.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on September 11, 2018, 01:37:51 AM
I didn't realize how big that engine is till seeing it with the collet block. Very nice!


For the brass parts like that, doing a stress relieving heat in the oven first would prevent that. Put the bars, degreased, before machining, in the oven at 500f for an hour and let it cool, thats it. Makes a huge difference in how it curves when cut. I try to load up all the bars for a project at once to limit how many times I have to run the oven like that, especially in the summer.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on September 11, 2018, 09:48:56 PM
Fitted the valve lifters and threaded the drill rod to hold them in place.

(http://www.pbase.com/kvom/image/168107385/large.jpg)

The valve movement as the eccentric turns is quite smooth, a nice surprise.  When I removed the cover to observe the valve it's off center.  It seems that I may need some more threads on the valve rod or thinner adjustment nuts.  That's for next time in the shop. 
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: steam guy willy on September 11, 2018, 10:22:25 PM
Hi Kvom ,will you be attaching the steam chest to the cylinder block with its own screws to keep it in place firmly when adjusting the valve  Just a thought as i usually do this....
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on September 12, 2018, 12:07:09 PM
Hi Kvom ,will you be attaching the steam chest to the cylinder block with its own screws to keep it in place firmly when adjusting the valve  Just a thought as i usually do this....

In the last photo you can see the heads of two screws just peeking out from the flange of the port block.  The 4 holes on the sides of the steam chest are through tapped, so that the steam chest remains attached with the cover removed.  The other 4 holes in the steam chest are not tapped.  I don't have any screws long enough at present, and in any case I intend to make studs for all 8 holes.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on September 13, 2018, 04:42:43 PM
First run on air

cso-hAlFizM
I was able to get the flywheel mounted using some .002" shim stock, but it is temporary as Chuck is sending me his Sanderson casting.  It is much closer to the type that would have been used on this type of engine and as drawn by Julius.  I'll probably need to remake the crankshaft to fit it properly.

Yesterday I finished 3 of the studs for the steam chest cover, so today I'll finish the other 5 and start thinking about the base.

Other todos:  powdercoat the valve lifters and the structural rods, plus finish the pump.  The governor as drawn will be a challenge, esp, its brackets, and I'll need to source some small bevel gears.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Admiral_dk on September 13, 2018, 05:02:02 PM
Congratulations on a very fine runner Kirk  :cheers:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: zeeprogrammer on September 13, 2018, 05:48:20 PM
Congrats!  :ThumbsUp:

It's a beauty. I love the action.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Kim on September 13, 2018, 06:28:57 PM
Very nice!  I'm with Zee - love that action, and the slow motion!
Kim
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Ye-Ole Steam Dude on September 13, 2018, 06:55:41 PM
Hello Kvom,

I second liking the slower speed, can view all the parts in motion a bit better. Beautiful job.

Have a great day,
Thomas
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on September 13, 2018, 09:03:27 PM
Wonderful motion and sound - congrats!
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on September 13, 2018, 09:14:24 PM
Thanks for looking in,

I finished the steam cover studs and ran it again with a pressure gauge.  The speed in the video is at about 20 psi, and it runs well at 15.

First issue found is that the motion of the vertical valve lifters causes the 4 nuts that attach them want to work loose.  The second issue is that the link between the eccentric rod and the lifters is a bit too long so that it flexes on each stroke. It would be good if I can shorten it
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: ShopShoe on September 14, 2018, 01:46:02 PM
That runs very well. Ditto on liking the speed and sound.  There is something about beam engines....

Thank You for posting.

ShopShoe
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: fumopuc on September 14, 2018, 07:21:02 PM
Congratulations for this runner Kirk.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on September 15, 2018, 04:03:26 PM
A little experiment in masonry.  I powder coated a small piece of aluminum orange and then machined grout lines into it.  The CAM programming was in error, but at least the effect can be seen.

(http://www.pbase.com/kvom/image/168122839/large.jpg)

Bricks on my house are 7x2" with 1/2" grout.  I decided a 1:8 scale would be appropriate to the engine, so the grout would be cut with a 1/16" endmill.  The pattern was generated in Solidworks using a 2 brick sketch expanded as a linear sketch pattern in 2 dimensions, so any size wall can be generated easily.  At 4000 rpm  and .006 DOC the recommended feed rate is 4 ipm, so a big wall would take a long time.  This will be a good change to try out my hi-speed spindle attachment that goes to 30K rpm.

All will have to wait until I get the flywheel and can design the base.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on September 15, 2018, 04:15:34 PM
Beautiful engine Kirk. Looking forward to seeing the final touches but the base looks great so far with the brickwork.

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Kim on September 15, 2018, 05:40:58 PM
That's a really interesting way to make brick!
Kim
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Larry on September 16, 2018, 03:14:47 AM
I have been waiting for this - CONGRATULATIONS ! Looks and runs great.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on September 18, 2018, 09:09:38 PM
I received in the mail today the lovely Sanderson flywheel donated by Chuck Fellows.  I hadn't realized that it was already machined  :cheers: with a 1/2" bore, so the first job is to remake the crankshaft to fit.  I turned down some 5/8" drill rod to 1/2" for the length of the flywheel hub, and after some finicky shaving got a nice sliding fit.

(http://www.pbase.com/kvom/image/168140181/large.jpg)

Test fit on the engine shows how much better it looks with this flywheel.

(http://www.pbase.com/kvom/image/168140180/large.jpg)

Normally I would have powder coated the spokes and hub, but I'm not sure how well it would adhere  to the grey paint.  In any case, the color seems harmonious.

Measurement shows that the bottom of the flywheel is 2.7" lower than the bottom of the base, so 3" brickwork seems the order of the day.  The outer edge of the flywheel is 1.5" from the edge of the base, which is 3.5" wide, so the brock base needs to be wider than 5" if I want the flywheel to be in a well.

Question for the knowledgeable:  In cases where the flywheel uses a well, is there a gap between the engine base and the wheel, or does the well have an inside wall separate?
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Ye-Ole Steam Dude on September 18, 2018, 09:36:51 PM
Hello kvom,

That new wheel is perfect for that engine, beautiful.

Have a great day,
Thomas
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: cfellows on September 18, 2018, 11:53:25 PM
For what it's worth, the paint on the flywheel is a special filler/primer.  It came in a rattle can but unfortunately I don't remember the brand or the name.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on September 18, 2018, 11:56:21 PM
Yes I agree, fits the engine size perfectly.

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: cfellows on September 18, 2018, 11:59:23 PM
Just did a little research and I believe the paint used was Plastikote filler / primer.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on September 19, 2018, 10:06:48 PM
To attach the flywheel to the crankshaft, I decided to use a key on the assumption that the Dumont minuteman broach kit I bought at a show a while back could cut it.  Not wanting to screw up the flywheel, I drilled and reamed a 1/2" hole in some scrap cast iron to try it out.  The kit contains 3 broaches, 1/16, 3/32, and 1/8 wide.  The 1/16 wide broach cut very easily, but the key was obviously too narrow for this use.  The 3/32 took more oomph on the arbor press and looked about right.  I tested the 1/8 broach over cutting the 3/32, and it looked too wide unless I wanted to shim for a second pass.  So I decided to use the 3/32.

Because the hub is so long, the broach doesn't quite make it all the way through, but since the key will be much shorter that doesn't matter.

(http://www.pbase.com/kvom/image/168144865/large.jpg)

For the corresponding slot in the crankshaft, I mounted it in a collet block and cut it .06" deep and .4" long with a 3/32" endmill (2000 rpm, .01 DOC).

(http://www.pbase.com/kvom/image/168144866/large.jpg)

For a temporary key, I whittled down a piece of brass until it fit.  I still need to remove the flywheel often, and this will be replaced by a steel key at a later date.

(http://www.pbase.com/kvom/image/168144867/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on September 19, 2018, 10:37:12 PM
Great looking flywheel, perfect style for that engine.


 :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on September 25, 2018, 08:14:51 PM
First run on air

How can you NOT LOVE this.  Superb!
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Tennessee Whiskey on September 25, 2018, 08:20:34 PM
I mustíve been on my way back from nowhere and missed the first run. Damn nice Kirk. Love the motion.

Whiskey
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on September 25, 2018, 11:22:50 PM
Currently trying to redo the two columns with a taper and capitals.  My lathe's taper attachment seems to be a bit out of sorts, and while it will cut a taper getting the taper to start in the proper place  is a no go.  I have two tapered sections in two pieces of aluminum rod, and I think I'll need to make the columns in 2 or 3 pieces.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Jasonb on September 26, 2018, 07:11:39 AM
Can't you just offset the tailstock and machine from one length. If you don't want to offset it use a boring head in the tailstock and a simple homemade ctr for it.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Zephyrin on September 26, 2018, 09:49:52 AM
Beautiful engine, top notch works...
the movement of these linkages to keep the piston rod in a straight line is fascinating to watch !
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on September 26, 2018, 12:49:25 PM
Can't you just offset the tailstock and machine from one length. If you don't want to offset it use a boring head in the tailstock and a simple homemade ctr for it.

I'm hesitant to move the tailstock.  I knew about the boring head option but it had completely slipped my mind.  I'll give it a try, as I have extra material.  The taper is pretty slight, 4 degrees included.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on October 01, 2018, 10:24:21 PM
Boring head technique for turning a taper will have to wait as my boring head takes 3/4" bars and has a 3/4" straight shaft, too large to mount in the largest drill chuck that fits my tailstock.  But I was able to use the section of taper generated by the taper attachment via trimming both ends of the work.

Here are the columns in place temporarily on the engine.  I intend to leave the base and capitols unpainted brass, and I'll powder coat the columns once I decide between red and grey.

(http://www.pbase.com/kvom/image/168201564/large.jpg)

I'm off on my fall trip on Thursday so I'm not sure when the next update will be posted.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on October 01, 2018, 10:30:08 PM
That taper does add a lot to the looks of the columns.
 :popcorn: :popcorn: :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Ye-Ole Steam Dude on October 01, 2018, 10:54:37 PM
Hello kvom,

Beautiful  :ThumbsUp:

Have a great day,
Thomas
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on October 10, 2018, 03:59:33 PM
This thing is,going to be colossiously gorgeous! !!
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on October 24, 2018, 10:36:46 AM
I've been away for 3 weeks visiting Jordan and Egypt.  After seeing the wonders of Petra and the Pyramids, it will be nice to get back to model building.  And jet lag means I get to browse the forum very early in the morning for the next week or so.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on October 24, 2018, 01:17:05 PM
I've been away for 3 weeks visiting Jordan and Egypt.  After seeing the wonders of Petra and the Pyramids, it will be nice to get back to model building.  And jet lag means I get to browse the forum very early in the morning for the next week or so.
Welcome back!  So with all that as inspiration, are the next parts of your engine going to be out of carved stone?!   :Lol:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on October 24, 2018, 04:38:19 PM
I'm waiting for you to make a stone submarine.   :stickpoke:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on October 24, 2018, 05:54:58 PM
I'm waiting for you to make a stone submarine.   :stickpoke:
I did a Marble polar bear, does that count? It would go right to the bottom...
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Ye-Ole Steam Dude on October 24, 2018, 06:05:22 PM
I'm waiting for you to make a stone submarine.   :stickpoke:


Hello kvom,

How about having Chris make a steam powered submarine :thinking:

Have a great day,
Thomas
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on October 24, 2018, 08:12:13 PM
I'm waiting for you to make a stone submarine.   :stickpoke:


Hello kvom,

How about having Chris make a steam powered submarine :thinking:

Have a great day,
Thomas
Its so hard to get a working nuke reactor that small (to drive the steam turbine) - and the water down the stack keeps putting out the coal fire!   :Lol:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on November 03, 2018, 12:22:20 AM
Having been afflicted with jet lag all week I refrained from working with power tools.  But that didn't prevent the wife from drafting me to change out a toilet and 3 light fixtures.  I guess working with electricity on a stepladder must be safer.   ::)

In any case, today I decided to do another experiment for powder coat brickmaking.  My first sample using just the orange power came out a bit too orange for my taste, so I mixed some orange and red powders in equal amounts and coated some aluminum scrap. Better but now too read.  Added more orange to the mix, and that looks about right, so 2:1 orange:red will be the goto for building the sub base.

Going over the Mic6 plate with some fine Scotchbrite before powder coating improves the powder adhesion and makes a much more even coating than the prior test.  I don't have to make the base out of this aluminum but I have quite a bit left over from the Colibri project,
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on November 23, 2018, 07:33:33 PM
With  Black Friday underway and me alone in the house, I decided to get back in the shop with the goal to finish the pump and its attachments.  Went to check the drawings and discovered my Solidworks license for 2018 has expired, and it will be next week until the new version can be downloaded.   >:(

I can at least make a start on the obvious parts.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on November 23, 2018, 11:03:36 PM
Hope you had a great trip Kirk. Nice to see progress on this beautiful engine.

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on December 09, 2018, 07:50:19 PM
Some slow paced shop time the past week or so.  Managed to finish the dummy pump, except for the gland, and its beam linkage.

(http://www.pbase.com/kvom/image/168516849/large.jpg)

I ordered some aluminum for the long sides of the "brick" base, but will plan to work on the ends in the interim.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on December 10, 2018, 10:18:51 PM
Over a year ago I bought a secondary high-speed spindle and made a mount for my CNC mill.  But I've never actually used it.  Now that I want to "engrave" the grout lines in the simulated brick of the engine's sub base, I decided to hook it up for some testing. 

Since the collets of the spindle limit me to 1/8" diameter tools, I can't use an edge finder to directly establish X/Y zeros on the stock.  To do this, I mounted a piece of scrap aluminum in the vise and used the spotting drill in the spindle to make a dimple.  Then zeroed the DROs.

(http://www.pbase.com/kvom/image/168522176/large.jpg)

Next I mounted a pointed center finder in the main spindle, lowered it by eye into the dimple, and then with the finder turning used the fine jog keys to determine by touch when the finder was centered.

(http://www.pbase.com/kvom/image/168522179/large.jpg)

The new values in the DROs show me the offsets between the two spindles.

(http://www.pbase.com/kvom/image/168522181/large.jpg)

I then mounted some scrap that I had used to test powder coating and used the spotting drill as an engraver.  The first two lines were at DOC of .01" and .02", 11K RPM and 100 IPM feed.  The .02 DOC looked about right for width of cut, but the slot was burred.  A third line at 20K RPM with the same feed rate gave a cleaner cut, and a fourth at 30K RPM showed no difference.

(http://www.pbase.com/kvom/image/168522183/large.jpg)

My previous test using a 1/8" endmill and 4000 RPM max on the main spindle resulting in a less than clean edge of the powder coat and a fairly slow feed rate.  This setup should be much less time to mill.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on December 10, 2018, 11:05:25 PM
Interesting setup, should open up all sorts of possibilities.


 :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on December 18, 2018, 09:53:10 PM
The aluminum I ordered for the sub-base finally showed up Monday, apparently delayed by the Xmas rush.  It will have the same dimensions as the regular base, that is 13x3.55" and 3" high to clear the flywheel.  The sides are 6061, 3x12x1/4, while the ends are1/2" thick Mic6 3x3.55" carved out of a piece of scrap left from the hummingbird build.

The 4 pieces will be joined by 1/16" diameter SS locating pins.  After machining all to size, I needed to drill holes for the pins.  The ends provided no problem, but the sides needed the holes drilled in the ends.  Here's the setup on the CNC mill for doing this:

(http://www.pbase.com/kvom/image/168556380/large.jpg)

I didn't need CAM to do this, as the gcodes for drilling are easy to just type in individually.

Here are the 4 pieces ready for the next step, which is powder coating a shade of red-orange to resemble bricks.

(http://www.pbase.com/kvom/image/168556382/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on December 20, 2018, 11:10:56 PM
Ready for some brickmaking.  Powdercoat the four sides of the base.

(http://www.pbase.com/kvom/image/168563976/large.jpg)

Cutting mortar lines with the hi-speed spindle and an engraving bit.

(http://www.pbase.com/kvom/image/168563977/large.jpg)

Rough assembly with locating pins to gauge general appearance.  I still need to engrave the mortar lines on the sides of the narrow ends.

(http://www.pbase.com/kvom/image/168563978/large.jpg)

I'd like to fill the lines with some white paint: spray on, wait a few seconds, then wipe leaving paint only in the grooves.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Ye-Ole Steam Dude on December 20, 2018, 11:37:51 PM
Hello kvom

That looks beautiful and will highlight the engine. :ThumbsUp: :ThumbsUp:

Have a great day,
Thomas
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on December 21, 2018, 12:20:02 AM
Great color combination, beautiful engine!
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on December 27, 2018, 07:20:40 PM
Time to start on the governor, although it may take a while.  The lower portion of the "drive train" has a horizontal shaft aligned with the crankshaft driving a vertical shaft via two bevel gears.  Using the gross dimensions from Julius' model, I found a matching gear and pinion at Stock Drive Products.  To verify how the gears would fit with the lower bracket, I downloaded the provided Step (.stp) files from the website, and had Solidworks convert these into part files.  Then I joined them with the bracket into an assembly.

I'll need to modify the bracket slightly to accommodate the collar of the large gear, but otherwise they look good.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on December 27, 2018, 10:46:24 PM
That base turned out very nice Kirk.  The whole project is just beautiful.

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on December 28, 2018, 09:28:55 PM
Today I made a start on the bracket.  It cannot be machined exactly as Julius modeled it, but in general it's close.  I took a piece of 1.5" square brass bar, squared it up with a face mill, and then made the first op on the CNC mill.

(http://www.pbase.com/kvom/image/168602988/large.jpg)

Second op was to profile the front and drill the mounting holes (5-40 clearance) and the 3/16" hole for the pinion shaft through the bottom.

(http://www.pbase.com/kvom/image/168602989/large.jpg)

Then cleared out the front to a depth of 19mm. Once my gear arrives I'll further remove stock to provide proper gear mesh.  Here's where it will stay until the gears arrive, probably around Jan.4.

(http://www.pbase.com/kvom/image/168602990/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on December 28, 2018, 09:44:41 PM
The connection between the large gear shaft and the crank pin is interesting.  Here's a closeup of the SW model:

(http://www.pbase.com/kvom/image/168603018/large.jpg)

The link has an eye on one end that rotates freely on the crank pin.  The other end passes through a hole in the shaft and is able to slide within it as the crank rotates.  This allows the gear shaft and crankshaft to be slightly misaligned.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Kim on December 28, 2018, 10:16:46 PM
That is an interesting setup. I've not seen that before.

Nice work on the bracket too, Kvom!
Kim
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on December 30, 2018, 04:52:59 PM
The upper bracket that holds the governor and attaches to the horizontal beam presents problems for fabrication.  Here is the bracket as designed by Julius.

(http://www.pbase.com/kvom/image/168609271/large.jpg)

I modified it slightly to accommodate the 3/16" shaft needed for the pinion gear, and uploaded it to Shapeways to see if it could be printed.  No go, as apparently there's too many unsupported features.  After some cogitation, I came up with a two piece solution as shown here.

(http://www.pbase.com/kvom/image/168609272/large.jpg)

The bracket in grey is relatively straightforward, while the arm will require some fixturing.  I tried the arm by itself in Shapeways and still a nogo.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on December 30, 2018, 05:15:04 PM
That looks like a part crying out for some silver soldering of arm to rods, then drilling the rods.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on December 31, 2018, 12:44:14 AM
That looks like a part crying out for some silver soldering of arm to rods, then drilling the rods.

But that's because you don't have the magic green button and have to mess with danger chemicals and fire.   >:D

I've been playing with CAM  this afternoon and have a fairly straightforward way to CNC the arm part.  I'll provide photos if it works and excuses if it doesn't.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on January 01, 2019, 12:44:35 AM
Did work on the bracket this afternoon.  Step one is cutting 2" of 1x1" brass bar on the bandsaw, then into the vise with a square to ensure it's upright.

(http://www.pbase.com/kvom/image/168615224/large.jpg)

Next, milling a 1/2" round boss:

(http://www.pbase.com/kvom/image/168615225/large.jpg)

Now it can be held securely in a 5C collet;  face the end.

(http://www.pbase.com/kvom/image/168615226/large.jpg)

Next, mount the collet in a square collet block with the sides of the bar parallel to those of the block.  Mount in the mill vise with a vise stop, and establish the zero coordinates:  Y centered on the block, X at the free end of the bar, and Z at the centerline of the bar.  By doing this the collet block can be turned in the vise and all 3 coordinate zeros stay the same.  To find Z0 for each tool, I touch off on a 1" gauge block setting on the collet block.  Since the collect block is 1.725" square, I can set Z to half of that plus 1 inch.

First cut is the side profile using a 3/8" 4-flute endmill.

(http://www.pbase.com/kvom/image/168615227/large.jpg)

Rotate the collect block and cut the partial top profile.  The drill and ream the 5/16" vertical hole.

(http://www.pbase.com/kvom/image/168615228/large.jpg)

(http://www.pbase.com/kvom/image/168615229/large.jpg)

Turn the collet block to drill and ream the 3/16" horizontal hole.

(http://www.pbase.com/kvom/image/168615230/large.jpg)

Finally finish both sides of the "neck":

(http://www.pbase.com/kvom/image/168615231/large.jpg)

The remaining work is to separate the piece from the remaining bar and finish profiling that end.

Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on January 01, 2019, 01:45:40 AM
Very nice result! Thats one of those parts where I would stop and go: lets see, turn THAT face up, no, wait, THAT one... Or...
 :popcorn: :popcorn: :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on January 01, 2019, 02:29:15 AM
Only 3 turns needed here.  I put all three views in the same DXF, which allowed me to make sure all were aligned properly.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on January 01, 2019, 10:17:50 PM
Machined the other, simpler part of the bracket today.  The arm still needs a fixture to finish rounding the end.

(http://www.pbase.com/kvom/image/168620922/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Ye-Ole Steam Dude on January 02, 2019, 08:49:18 AM
Hello kvom,

That is some beautiful work.

Have a great day,
Thomas
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on January 06, 2019, 12:50:10 AM
My gears arrived on Friday, so it was time to get back on the governor.  First was to clean up the "arm" of the upper bracket where it was attached to the parent stock.  Here's the setup I used on the CNC mill.

(http://www.pbase.com/kvom/image/168651286/large.jpg)

I used Loctite 620 to attach a short length of 5/16 drill rod; then clamping in the machinist vise's v-slot ensured it was vertical.  Then a series of slow 180-degree passes removed the unwanted portion.  Afterwards I put the assembly in a 500-degree oven for half an hour, then used my arbor press to remove the rod.

Then a test fit of the two gears to the lower bracket while still attached to the bar.

(http://www.pbase.com/kvom/image/168651287/large.jpg)

I removed some bracket material with the side flutes of an endmill until the pinion shaft looked vertical.  This may need to be done again once I have the upper bracket in place with a full-length shaft.  But for now I could saw off the bracket and face mill off the saw marks.

Neither of the gears had set screws, so it was necessary to drill and tap 8-32 on the larger gear.  I did this with a piece of 3/16" brass rod inserted to avoid burrs on the bore.

(http://www.pbase.com/kvom/image/168651288/large.jpg)

With the bracket attached to the engine's base, I can start to do some more fitting.

(http://www.pbase.com/kvom/image/168651289/large.jpg)

As I mentioned in a previous post, a follower is needed on the crank pin to drive the gear train.  To make this I started by carefully turning some half inch brass rod down to 7/16 (0.4375).  Then I drilled some 3/8" drill rod and reamed to .4365.  Both the brass and the edge of the hole had a slight chamfer.  Then I used my arbor press to join the two.  After drilling and reaming the brass 5/16", I faced both ends to length.

(http://www.pbase.com/kvom/image/168651290/large.jpg)

Then I drilled and tapped a cross hole 5-40 for a 1/8" rod.  Together with the spacer seen below, turning the crank now also turns the gear:

(http://www.pbase.com/kvom/image/168651291/large.jpg)

The drive rod needs to be shortened and the spacer cleaned up, but I'm happy with the results thus far.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on January 06, 2019, 01:03:35 AM
All that CNC and you didn't cut the gears?


 :stickpoke: :stickpoke:    :Lol:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on January 06, 2019, 02:55:06 AM
I cut a check.  Does that count?  :shrug:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Kim on January 06, 2019, 05:33:17 AM
I cut a check.  Does that count?  :shrug:
Apparently it does count!  You've got the gears, and they seem to be doing the job!  :Lol:
Kim
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: b.lindsey on January 06, 2019, 01:00:55 PM
Very interesting governor mechanism Kirk and should add a lot of interest to the model too. Still watching along.

Bill
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Admiral_dk on January 06, 2019, 10:09:23 PM
Great result Kirk + it will make people take a second look when it is running  :ThumbsUp:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on January 07, 2019, 09:45:14 PM
Impressive work; I was wondering how you were going to make that bracket.  Thanks for the step photos.  :cheers:

Following along  :popcorn: :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on January 27, 2019, 03:39:48 PM
I've been laid up with a pulled muscle in my back since Thursday, and have been playing with generating STL models of some gears.  I loaded one of them into Shapeways and notices that the upload of an STL file created in metric needs to be specified as inches to get it sized correctly.  I went back and looked at the governor bracket that seemingly couldn't be printed now is possible once properly resized.  Still not cheap and 10 days to deliver.

The wheel gear I modeled is about the same size as the one I ordered from SPI, and printing in brass would be similar cost.  In steel about half price.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on January 27, 2019, 04:04:34 PM
I've been laid up with a pulled muscle in my back since Thursday, and have been playing with generating STL models of some gears.  I loaded one of them into Shapeways and notices that the upload of an STL file created in metric needs to be specified as inches to get it sized correctly.  I went back and looked at the governor bracket that seemingly couldn't be printed now is possible once properly resized.  Still not cheap and 10 days to deliver.

The wheel gear I modeled is about the same size as the one I ordered from SPI, and printing in brass would be similar cost.  In steel about half price.
I noticed the same thing on Shapeways recently when I uploaded some parts for an engine, they came out tiny till I resized them, no change to dimension but clicked on inches. They seem to be ignoring the inch/metric button till after the file is loaded.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on January 29, 2019, 10:39:58 PM
Continuing on with governor parts as time allowed over the past two weeks.  The pivot was a particularly tricky on, and I had to scrap three of them before getting a useable part.  First op was profiling from a piece of 2x1x1" brass bar to get two parts.

(http://www.pbase.com/kvom/image/168754226/large.jpg)

Then turning 90 degrees, mill out the open pocket.

(http://www.pbase.com/kvom/image/168754227/large.jpg)

Then relieving the "arm" on the opposite end.

(http://www.pbase.com/kvom/image/168754228/large.jpg)

After cutting the two pieces apart, the remaining op is to remove the remaining stock where the part is still attached.  Because the part is difficult to chuck in a regular vise, I decided eventually to machine a set of soft jaws.

(http://www.pbase.com/kvom/image/168754229/large.jpg)

Then I moved the jaws to the Bridgeport and face milled gently.

(http://www.pbase.com/kvom/image/168754230/large.jpg)

Finally a family shot of parts made to date:

(http://www.pbase.com/kvom/image/168754232/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on January 29, 2019, 11:10:06 PM
A part I'd done previously and forgot to show.  The lower sliding collar of the governor.  Again, using 1x1" brass bar, the profile is machined into the end of the bar.

(http://www.pbase.com/kvom/image/168754472/large.jpg)

Next, a 3/16" hole is drilled halfway through the bottom and reamed.

(http://www.pbase.com/kvom/image/168754473/large.jpg)

On the top, a center drill is used.

(http://www.pbase.com/kvom/image/168754474/large.jpg)

After sawing the piece free from the stock, one can see how the part will be able to be turned in later ops.  But next, the bottom is milled round.

(http://www.pbase.com/kvom/image/168754476/large.jpg)

And the reduced neck is turned with a parting tool.

(http://www.pbase.com/kvom/image/168754477/large.jpg)

After this, the top is milled to correct width and a length of 3/16" drill rod was loctited into the bottom.  After curing for over a week, the piece was back on the lathe with the drill rod help in the collet check and supported by the live center.  This allowed the slot to be turned in the bottom portion to fit the arms of the pivot (can be seen in the family shot of the previous post).

Now the problem is to remove the drill rod and finish drilling and reaming through the entire part.  I put the assembly in a 500F over for an hour, but it didn't release.  Fiercer methods were called for, and with the drill rod clamped in the bench vise I heated it all with the torch.  It was very surprising when the part flew into the air with a POP!  It seems that there was a pocket inside with some unsolidified loctite that boiled, creating enough pressure to blow it off.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on January 30, 2019, 12:38:19 AM
Nice  :ThumbsUp: :ThumbsUp: :ThumbsUp:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Admiral_dk on January 30, 2019, 11:19:34 AM
You have really made some nice parts using the CNC mill the best possible way Kirk  :ThumbsUp: and showing that planning the work sequence is just as important as with manual tools too.

 :cheers:    :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Dave Otto on January 31, 2019, 01:00:26 AM
Nice work Kirk!

Dave
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on February 02, 2019, 06:08:51 PM
Next governor parts are the lower arms, rather small finicky things.  After some thinking, I decided to use a technique learned from Terry Mayhugh on the other forum.  Using a piece of 1" square brass bar, the profile is machined into each end of the bar.  The vise stop means I can turn the bar over and reuse the same tool change.

(http://www.pbase.com/kvom/image/168768987/large.jpg)

Next, the cavities around the part are filled with epoxy, in this case "Devcon 5" purchased at Lowes.  This was allowed to cure overnight.  Note that for future machining the epoxy must be constrained by metal on at least two sides.

(http://www.pbase.com/kvom/image/168768988/large.jpg)

After curing, I did a skim to ensure that the surface would be flat for mounting in the vise.  Then I cut off each end leaving a good margin for safety with the horizontal bandsaw,  Then mounted one in the Bridgeport vise and used a face mill to gradually reveal the part's outline.

(http://www.pbase.com/kvom/image/168768989/large.jpg)

The parts were then placed in the oven at 500F for an hour.  I seem to remember now that Terry put them in boiling water, but in any case the epoxy releases with a bit of effort with needle nose pliers.

(http://www.pbase.com/kvom/image/168768990/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: fumopuc on February 03, 2019, 07:36:02 AM
Hi Kirk, I think I have to file this process away for future issues also. Thanks for showing it.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on February 03, 2019, 11:27:19 PM
Today I made a start on the upper arms of the governor, those that connect to the balls.  Because I have a good deal of 3/16" square brass bar, I decided to redraw the part in Solidworks using imperial units.  After cutting two pieces over length at 1.75", I used a 3/16 square collet to drill .07" holes 0.2" deep in one end.  These will be tapped 2-56.

(http://www.pbase.com/kvom/image/168772796/large.jpg)

Next each bar was reduced to 1/8" thickness by milling 1/32" off of each side.  The first cut was easy, but the reverse side had the vise holding onto a tiny fraction of the bar.

(http://www.pbase.com/kvom/image/168772797/large.jpg)

To drill the mounting holes for the governor's upper section and lower arms, I mounted the vise stop and zeroed the DRO on the corner of the small vise's fixed jaw.

(http://www.pbase.com/kvom/image/168772798/large.jpg)

Then with the small vise on the surface plate, I used a 123 block to fix the drilled end of the part level with the side of the vise jaws.  Then I could replace the vise on the large Bridgeport vise and locate the holes accurately.

(http://www.pbase.com/kvom/image/168772799/large.jpg)

For the balls themselves, I tried some chromed balls I had on hand.  Mounted on the lathe and faced a flat area to mate the arm.  However, the ball was too hard for my HSS spotting drill to penetrate (drill tip was dulled).  So I've ordered some brass balls from McMaster and I'll try those later in the week.

(http://www.pbase.com/kvom/image/168772800/large.jpg)

Last op for the day was to tap the ends of the arms on my tapping stand.

(http://www.pbase.com/kvom/image/168772801/large.jpg)

There's still some more work to do on the arms, but I need to solve some workholding dilemmas first.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on February 04, 2019, 12:26:26 AM
Nicely done. The brass balls will be easy to drill, also a little more mass to them.


 :popcorn: :popcorn: :popcorn:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on February 05, 2019, 09:13:56 PM
The brass balls arrived this afternoon earlier than usual for UPS.  Not as easy to drill as Chris imagines as the first attempt resulted in a broken .070" drill in the hole, but cutting the peck size to .03", feed 3 ipm, and 4000 rpm did the trick.  Here's the setup:

(http://www.pbase.com/kvom/image/168779571/large.jpg)

Using the v-groove in the vise's moveable jaw along with the vise stop meant that I could retain my XY zero after removing the small vise to change balls.  The process I used was to mill a flat on the ball with a 3/16" endmill, then spot drill, and finally peck drill .200" deep.  Then I could take the vise and ball to the tapping stand, so that the hole was still vertical with regard to the base.

The balls are then attached to the upper arms of the governor using some 2-56 threaded rod.

Here they are in place:

(http://www.pbase.com/kvom/image/168779572/large.jpg)

Because the end of the support rod is larger than in the SW model, I need to make the sliding collar spacer longer to avoid the balls hitting the rod end.  The space between the sliding collar and the top of the bracket is close to 5/8" vs. the planned 8mm.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on February 07, 2019, 11:53:09 PM
Since the last update I powder coated the upper and lower brackets.  Here is a shot of the governor pre-assembly showing the brackets and rotating parts.

(http://www.pbase.com/kvom/image/168788911/large.jpg)

Upon mounting to the engine, it's evident that there are some problems.  At the maximum permitted by the pivot, the balls will contact the conrod.

(http://www.pbase.com/kvom/image/168788912/large.jpg)

At the pivot rest position the balls hit the support bar.

(http://www.pbase.com/kvom/image/168788913/large.jpg)

I did notice that the balls' arms are  .020" longer than the SW model given how I machined the flat on the balls.  Also, the ball in the photo is not screwed all the way flush with the arm.  While I can make the flat spot on the balls larger and shorten the arms as well, I can also change to .5" balls from the current .625" ones.  Whether the engine can turn fast enough to raise the collar so that the balls will interfere with the conrod is unknown.  If so, a stop ring between the fixed and sliding collars can be added.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on February 10, 2019, 11:09:59 PM
After replacing the 5/8" balls with 1/2" ones and some other adjustments, the governor now spins without interference.  It has a vertical travel of only 1/8" as restricted by the pivot.  I could increase it some by filing the pivot arms, but as I like to run engines at slow speed, I doubt the governor will actually move much at all.

Here's current state of the project.  I still need a dummy valve that lies under the steam chest and is connected to the governor's pivot arm.  Other than that not much but little stuff.

(https://pbase.com/kvom/image/168799935/large.jpg)

Height gauge is set at 12" for comparison.  Highest point of the beam is 14.5".
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on February 10, 2019, 11:16:28 PM
Very very well done!!
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Admiral_dk on February 11, 2019, 12:18:11 PM
I looks amazing Kirk  :cheers:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on February 17, 2019, 03:35:26 PM
The last major piece needed for this engine is the valve that's regulated by the governor.  As drawn by Julius, here's the head on view:

(https://pbase.com/kvom/image/168828714/small.jpg)

One can see that the critical size are that its top be below the bottom edge of the steam chest cover and its bottom edge above the cross shaft that links the pushrods.

The side view shows its position relative to the steam chest:

(https://pbase.com/kvom/image/168828715/small.jpg)

As drawn, the connection is a flanged elbow of just the right dimension, something that's quite difficult to concoct.  When I first assembled the engine for its trial run, I had a brass elbow with a 1/16 NPT male end screwed into the bottom of the steam chest.  As you can see, the female opening is too high to allow the valve or a close approximation thereof to work.

(https://pbase.com/kvom/image/168828712/medium.jpg)

I decided to replace this with a nipple and an elbow.  Since 1/16 NPT fittings aren't available generally in local stored, I made one from some 1/2" hex brass rod.  It's quite difficult to get precise dimensions from such fittings, but this seems close enough.

(https://pbase.com/kvom/image/168828713/large.jpg)

I'll measure the top and bottom clearance from the center of the pipe, and redraw the valve to fit.

On another front, Eastwoods had a Valentine's day sale with free shipping, so I ordered some "chrome" powder.  If it looks good on a test piece, I'll powdercoat the brass support beams to look more like steel.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on February 22, 2019, 03:47:12 PM
I made an initial dummy valve and mounted it with a nipple.  Turns out it sits far enough clear of the steam chest cover that I can make it much closer in size to that drawn by Julius.  So that's a current to do.

In the interim, the chrome powder arrived from Eastwood, so I powder coated a couple of pieces of scrap brass.  Not as shiny as actual chrome plate, but I think a metallic finish for the links is preferable than brass.  So I dismounted the 6 bars at the cylinder and coated them:

(https://pbase.com/kvom/image/168846818/large.jpg)

I started to reassemble and had a small disaster.

(https://pbase.com/kvom/image/168846819/large.jpg)

Seems I drilled/tapped the end too deep so that the walls at the joint were too thin.   :(   So I'll need to remake it and its partner, this time in steel.  I ordered a 3' piece of 1144 5/8" diameter rod from McMaster.  It out to arrive tonight.  If things work out I may just remake all 8 bars.  Hopefully I can get a better finish too.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on February 22, 2019, 03:51:54 PM
Ouch on the bars, but at least you know the new powder coat looks good.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on February 26, 2019, 12:56:25 PM
The powder coat looks great!

"Little disasters" are just part of the game.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on February 26, 2019, 09:54:09 PM
Having received 3' of 5/8" 1144 steel rod, I proceeded to attempt to duplicate the broken vertical stay.  What followed was success followed by  other disaster.  That said, I think I have found a sound way forward to replace all 8 of the stays with steel.

After cutting and facing to length, I mounted the rod in a collet block, clamped in the vise against a vise stop, and zeroed the mill.

(https://pbase.com/kvom/image/168863256/large.jpg)

Then milled the two sides of the rod to 7mm thickness.

(https://pbase.com/kvom/image/168863257/large.jpg)

The vise stop allowed me to turn the collet block 90 degrees and refasten without losing my zero.  The same endmill then profiled the head.

(https://pbase.com/kvom/image/168863258/large.jpg)

After drilling a reaming a .251" hole through the head:

(https://pbase.com/kvom/image/168863259/large.jpg)

Moving to the lathe, the base is turned to .375" allowing holding from this end.  Drilled and tapped 8-32.

(https://pbase.com/kvom/image/168863260/large.jpg)

I reversed the work in the lathe and center drilled the head with a #1 center drill.  When I started to turn the shaft, it became clear that then live center wasn't turning.  After examination, I discovered that the sharp point of the live center had become dulled somewhere or other and didn't fit the hole.  Rather it had broken the thin wall between the hole and the edge of the head.   :facepalm:

I managed without using a center to turn the shaft down to just over 6mm by progressively exposing about 10mm of shaft from the collett.  Once I had done the entire length, I used a parting blade to try to even up the diameter, cutting about .002" deep each pass.  Then after some sandpaper and scotch brite, the shaft looked decent but not perfect.

So now the goal was to machine away the top of the head with the ugly hole.  To hold the piece, I tried clamping in a V block using a height gauge to ensure the head was horizontal.  Then clamped in the Vise and used a wiggler center  finder to zero on the center of the hole.

(https://pbase.com/kvom/image/168863261/large.jpg)

Then came disaster #2.  The clamp isn't strong enough to resist machining forces, so the first endmill contact caused the piece to both slide back and rotate.

(https://pbase.com/kvom/image/168863262/large.jpg)

Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on February 26, 2019, 09:56:20 PM
Going forward, my intention now is that each stay will have separate heads made as above, connected by some 7/32" diameter drill rod for the shafts.  They will be assembled with loctite using a jig for proper spacing.

Probably no shop time until Thursday.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on March 01, 2019, 11:12:15 PM
Started on the "separate head" idea and discovered that with a 6mm width, the 7/32 shaft is too close to the walls.  So now the head will be 7mm thick , and the neck 7mm wide.  Did a trial single that seems to work.

Workflow for each:

Op1:  mill sides to get 7mm thickness
Op2:  turn 90 degrees and mill head profile
Op3:  spot drill
Op4:  drill 11/64 through
Op5:  ream .251
Op6:  Move to lathe and part off leaving .2" of rod attached for holding in the collet
Op6:  Insert head into the collett and face
Op7:  spot drill

Next on the mill mount the collet chuck and center.  The collet will have a collet stop so that the target depth of the 7/32 drill is constant regardless of the amount of material on the base of the head.

Op8:  Insert head first into the collet against the stop and tighten.  Peck drill 7/32.
Op9:  Back to lathe to part off the completed head.

Tedious because of tool changes, but I got 5 of the necessary 14 complete through Op7.

Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on March 09, 2019, 12:45:06 AM
Got the stays finished after several short shop sessions during the past week.  Here's the result of swapping ends in the collet block and machining the other end:

(https://pbase.com/kvom/image/168894675/large.jpg)

Part in two, drill 7/32 hole in the end, and then part at the "neck".  I did these two to verify the process.

(https://pbase.com/kvom/image/168894676/large.jpg)

Here's the rest waiting to be drilled.  I spet drilled the ends on the lathe after parting and facing.

(https://pbase.com/kvom/image/168894678/large.jpg)

To get a consistent depth drilling, I used this setup with a collet stop in the collet.  I measured the first piece to determine how deep to go from the exposed end, then set that at Z0.  Thus, none of them risked the drill breaking into the cross hole.

(https://pbase.com/kvom/image/168894677/large.jpg)

Each pair of stays have different lengths than the other pairs.  This fixture allow assembly.  I used a 1/14" endmill to drill properly spaced holes that accept some 1/4" drill rod in a tight fit.  Then cut some 7/32 drill rod to fit tightly in each end while the ends are held by the pins.  Basically started with each rod a bit long and whittled down on the lathe until a good fit was attained.  Then Loctite 620 on the ends and back onto the fixture to cure.

(https://pbase.com/kvom/image/168894679/large.jpg)

Here are the 4 pairs:

(https://pbase.com/kvom/image/168894680/large.jpg)

To fit the single ended (vertical) ones, I scribed a line along the Y axis at X0, the drilled a hole at X 90 mm.  Then adjusted the length of the rod until the bottom lined up with the line.

Since I made the heads 1mm wider than the old ones, I'll need to adjust the spacers on the cross rods when I reinstall them.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on March 09, 2019, 12:59:24 AM
Very nice!

I have never seen a collet holder like that - looks like a wheel hub? What is the black ring, and why does the holder flare out like that?
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on March 09, 2019, 02:14:39 AM
It's a Hardinge collet chuck that mounts on my lathe with a d1-3 spindle.  The black ring is turned to tighten/loosen the collet.  I have a repurposed d1-3 spindle nose clamped in the vise that allows me to mount lathe chucks on the mill.

In the past its main used was holding round stock for thread milling studs.  Very handy for the Jpy engine build.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on March 13, 2019, 02:20:22 AM
An afternoon in the shop allowed some decent progress.  After installing the steel stays, which went fairly well with only some trimming on a few spacers, I wanted to fabricate a way to attach the bottom of the engine to the brickwork.  To do this, I squared up two pieces of 1/2" aluminum that are attached to the end walls with 8-32 screws. 

(https://pbase.com/kvom/image/168911498/large.jpg)

The lower base of the engine was separated by removing the 6 screws, and I drilled and countersunk holes on each end for 8-32 screws.  Then after placing the base onto the brickwork, I used a transfer punch to mark the blocks on the walls.  Then the blocks were drilled and tapped, so that the base could be attached firmly.  Since the base and brickwork can be separated easily from the engine, it will make transporting it more easily separately.

(https://pbase.com/kvom/image/168911499/large.jpg)

The engine as it now sits:

(https://pbase.com/kvom/image/168911500/large.jpg)

The major pieces left to do are those for connecting the governor collar to the dummy valve.

Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on March 14, 2019, 01:57:53 AM
Notice how I emulated George Britnell and show a penny for scale.   ;)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: yogi on March 14, 2019, 02:34:15 AM
Beautiful engine Kirk! Coming together nicely.  :popcorn: :popcorn: :popcorn:

Are you sure thatís the same penny George is using?  :stickpoke:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on March 14, 2019, 10:52:55 AM
George uses an older, more elegant, wheat cent reverse.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on March 14, 2019, 06:21:16 PM
Very nice Kirk.  Looks grsat.

George uses an older, more elegant, wheat cent reverse.

I'm STILL convinced George has a 'special' penny he uses for scale.  :lolb:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on March 14, 2019, 06:55:19 PM
Very nice Kirk.  Looks grsat.

George uses an older, more elegant, wheat cent reverse.

I'm STILL convinced George has a 'special' penny he uses for scale.  :lolb:
Nah, he has that shrinking machine from Fantastic Voyage!
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on March 28, 2019, 04:28:58 PM
After some intermittent shop time I finished the governor link, shortened and replaced some screws, and figured I was ready to retime the engine and see how it runs.  All went well for a few minutes; found some interference between the conrod and governor connection and fixed that.  The after some more "air time" the engine stopped running.

I removed the steam chest cover and discovered that the valve travel had changed.  There is a fair amount of wiggle in all the linkages between the valve rod and eccentric, but the main culprits seem to be the two nuts at the end that position the valve in the center of its motion.  They need jam nuts or lock washers to prevent the motion from loosening or turning the rod.  The rod is too short for these.  The alternative to doing so is to make the hole through the crossbar threaded.  Then the two nuts would be jam nuts themselves.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Jasonb on March 28, 2019, 05:27:56 PM
To save remaking parts could you add a set screw hole at right angles through the cross bar to lock the rod in place once it has been adjusted with the screws?
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Gas_mantle on March 28, 2019, 05:35:52 PM
Its looking great Kvom, not long till it's finished  :)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on March 28, 2019, 08:24:17 PM
iZbjtIejKK8
I have a problem with some nuts, esp. 2-56 working loose during running.  I suspect blue thread locker is needed unless members have better ideas.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on March 28, 2019, 08:29:12 PM
The blue is good - keeps vibration from loosening things, but you can adjust/remove them as needed without heating. I learned the hard way to remember to shake the tube to remix the components of the blue/red versions.

Great action and sound on the model!!
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on March 29, 2019, 02:29:25 AM
As Spock would say.... "Fascinating!"  :ThumbsUp: :ThumbsUp: :ThumbsUp:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on March 29, 2019, 07:08:47 PM
Loctite now supplies blue threadlocker in a red tube.  wtf!   :headscratch: :shrug:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: crueby on March 29, 2019, 09:02:24 PM
Loctite now supplies blue threadlocker in a red tube.  wtf!   :headscratch: :shrug:
They have been doing that for a long time - the tubes/bottles I have are all red on the outside, for the blue, green, red loctites... They seem to just use the numbers and names to differentiate them now. Low strength blue, high strength red, etc. I think the company got bought/sold a couple times and every owner changed things.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on March 29, 2019, 10:41:54 PM
After applying the thread locker to the most suspect threads, I've run the engine for a while until it eventually bogged down.  I found that the motion was quite stiff and couldn't figure it our got a while until I notices that the eccentric strap was loose.  Thread locker on those loosened it back up.

That said, I think a basic engineering issue is that the eccentric rod transmits its motion to the valve lifters by a horizontal rod, and this rod flexes back and forth on each rotation. (pic attached).

I believe a solution will be to make a part similar to the part that connects the rod to the valve lifter and position it to the other side of the lifter and the mounting bracket.  That will result in both a shorter horizontal rod and a more rigid connection to the lifter.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Jasonb on March 30, 2019, 07:12:37 AM
Yes, longer rod with an arm mounted outside the bracket so you can have the arm and rod join side by side and keep the lever to the vertical rod on the inside. This is how both my Stuart and Easton & Anderson are done. Ideally these linkage arms should be fixed with taper pins to the cross shaft so there is no risk of then slipping.

More importantly that's how Muncasters original drawings show it.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on April 02, 2019, 12:46:30 AM
Started first side of the rocker.  After drilling the holes for the connecting rods, I milled the profile 10mm deep using trochoicdal paths.

(https://pbase.com/kvom/image/168989835/large.jpg)

Then pocketed to reveal the boss that will connect to the eccentric rod, followed by a finishing pass on the profile.

(https://pbase.com/kvom/image/168989836/large.jpg)

Finally, filled the cavity with epoxy gel that will hold the part after machining from the opposite side.  I am leaving to to cure overnight.

(https://pbase.com/kvom/image/168989837/large.jpg)

The machining for both sides has 0,0 as the center of the stock; and since I positioned it using a vise stop, it suffices to flip along the Y axis for the next ops.  The "drawing" for the back obviously needs to be mirrored on Y as well.

Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on April 02, 2019, 11:05:25 PM
Machining the opposite face; the epoxy keeps the work from moving.

(https://pbase.com/kvom/image/168995137/large.jpg)

Afterwards I placed the piece in a pan of boiling water for about 30 minutes total.  Still took some effort to release and then clean up.  Then trial fit on the engine.

(https://pbase.com/kvom/image/168995138/large.jpg)

It needs a bit of adjustment followed by powder coat to match the two other pieces.  And two cross shafts need to be remade longer.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on April 06, 2019, 03:31:24 PM
After remaking the cross shafts and getting all the fasteners on, the amount of flex in the horizontal rod is much reduced, and appears only in the the rod end of the eccentric rod, where the fit is fairly loose.  I ran it sitting on the Bridgeport table, and it has a tendency to walk.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on April 10, 2019, 08:19:06 PM
I'm declaring this engine finished.  No good place for photos in the shop, so here she in on the dining room table.

(https://pbase.com/kvom/image/169041653/large.jpg)

(https://pbase.com/kvom/image/169041654/large.jpg)
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: cheepo45 on April 10, 2019, 08:22:11 PM
Very Nice!
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Admiral_dk on April 10, 2019, 10:10:04 PM
She looks fantastic Kirk  :praise2:  any chance of a video  :thinking:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Johnmcc69 on April 10, 2019, 10:26:59 PM
She's a beauty KVOM. Really nice work.  :ThumbsUp:

 Would love to see it running!  :stickpoke:

 John
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on April 10, 2019, 11:38:13 PM
Video is a few posts prior.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Larry on April 11, 2019, 03:58:04 AM
Love that engine. Great job ! Glad I got to see it in person.
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: Craig DeShong on April 15, 2019, 12:57:44 AM
Super nice Kirk, congratulations  :NotWorthy:
Title: Re: Muncaster Grasshopper - Work in Progress
Post by: kvom on May 04, 2019, 07:54:39 PM
I took the engine to NAMES and ran it a short while before running into a couple of issues.  The first was that the gib key was a bit loose allowing the flywheel to work loose after some time.  The other was that the grub screw for the eccentric would work loose, obviously causing the operation to stop.  As it happens the screw itself was aligned with the crank web afer timing, so I could fasten it again and keep running.  I also noticed that the flywheel wasn't running true either.

This morning I removed the crank assembly and added additional grub screws for the crank web and eccentric.  There is miniscule clearance in the bearing that still allows a bit of wobble when viewing the flywheel rim, but it's much closer to true.