Model Engine Maker

Engines => Your Own Design => Topic started by: vtsteam on November 27, 2022, 04:37:38 AM

Title: Small Flash Single
Post by: vtsteam on November 27, 2022, 04:37:38 AM
Well this is a first engine here for me -- I started it about a week ago. Very aware of the very high level of workmanship and complexity I've watched over the years here in the amazing projects people do. And a little nervous about posting!

This engine is intended as a 1" bore and .75" stroke single that I'd like to power with a wood fired flash plant and possibly power a small generator. The engine design is heavily influenced by the Westbury/Spartan, Kirtley/Pisces, and especially the KBC/OOYA marine model lineage, as is probably obvious. One small difference is that the crankcase and cylinder will be iron, and cast as a whole. Weight is not a drawback in a small stationary engine, and it's easy for me to cast full components in iron.

Since this isn't a racing engine, it's going to be a little more conservative in build and in performance. I have to admit to a pipe dream that, if it works out, I'd like to try my hand at a double size version for use as a steam powered outboard motor. But that's a whole separate topic.

Anyway, here is the start I made last week. An initial drawing of the crankcase and a simple pattern. I decided not to core the pattern to make it easier to avoid chilling the thin sections, and shrinking the thick ones:


(https://www.sredmond.com//srhacksaw/FlashEngine1x75/1x15SCEngineBlock.png)
Title: Re: Small Flash Single
Post by: vtsteam on November 27, 2022, 04:43:22 AM
This was the pattern I glued up:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Pattern1.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on November 27, 2022, 04:44:25 AM
And then painted:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Pattern2.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on November 27, 2022, 04:50:11 AM
We had some unseasonably cold temps and high winds for a few days but eventually it warmed up a little and I was able to melt some iron and pour the mold. I was a little out of practice in casting, so it took a few hours for me to mold the pattern properly and get the furnace burner cleaned and back in operation. The pour did go well after that with no real problems.


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/CrankcasePour1.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on November 27, 2022, 04:53:03 AM
I waited 3 hours to break open the mold. There was some shrinkage in the new casting, but enough machining allowance to compensate for it.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/CrankcaseCasting1.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on November 27, 2022, 04:54:58 AM
Cleaned up:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/CrankcaseCasting2.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on November 27, 2022, 04:59:34 AM
Next up came boring the cylinder. I decided to do that before clearing out the crankcase bore, since the casting could be held more easily with a solid base:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/CylinderBoring1.jpg)

Title: Re: Small Flash Single
Post by: Kim on November 27, 2022, 05:03:46 AM
Doing your own castings seems like quite a challenge, and it sure looks nice!

Kim
Title: Re: Small Flash Single
Post by: vtsteam on November 27, 2022, 05:05:12 AM
At the same sitting, I turned the top flange and the exhaust chamber. Uniflow ports will later be milled at the bottom of that chamber into the cylinder.

An outer manifold ring will set down over the top flange and mate with the groove at the bottom of the exhaust chamber. The top of the ring will be flush with the top flange and the head will seal against both.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/CrankcaseCasting3.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on November 27, 2022, 05:15:43 AM
Thanks Kim! I do love casting, though it can be frustrating at times. I think I lucked out a little on this first one after a long period of inactivity for me. It took re-molding the pattern a couple times because I forgot one or two steps. But I didn't rush it, and went back and re-made it.

Here's the front bearing housing drawing and pattern, and where I am so far. Though I might not cast the valve guide boss as shown. I can't clean up the casting in the lathe if I do it this way, and I don't have a rotary table for the mill. So maybe I'll make the little cubic block separately and braze them together after turning the main part.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Pattern3.png)
Title: Re: Small Flash Single
Post by: Zephyrin on November 27, 2022, 10:30:25 AM
your own castings in iron, and getting machinable parts; wow! congratulations !
Title: Re: Small Flash Single
Post by: Alyn Foundry on November 27, 2022, 12:20:27 PM
Well done, vtsteam.

I can still remember, vividly, my first success with casting in Iron. Just a simple part for one of my vintage Lister engines. That was nearly 40 years ago now, see attached snippet from an article I wrote for Stationary Engine magazine.

The choice of the scrap to be melted plays the most important part in determining the outcome. I was lucky to have a friend who’s profession was in metallurgy. He recommended the crankcases from the now defunct Suffolk Iron foundry lawnmower engines. If melted quickly the Iron would not loose much of its core ingredients.

Needless to say as demand grew for my engine kits and being in full time employment I had to start using a commercial Iron foundry.

Home casting isn’t beyond the capability of anyone willing to have a bash and the end result provides immense satisfaction.

 :cheers:  Graham.
Title: Re: Small Flash Single
Post by: vtsteam on November 27, 2022, 11:54:03 PM
Thank you kindly Zephyrin and Graham!  :cheers:

Graham I have an Indian Lister clone which has served us for a decade as a backup home power supply during outages.... generally 3 or 4 times a year around here. The 600 rpm chug, chug, chug is far more pleasant on the ears than our former 3600 rpm Generac racket maker!

It was one of the last Lister clones imported before that was blocked here because they didn't have modern diesel emissions certifications. 
Title: Re: Small Flash Single
Post by: vtsteam on November 28, 2022, 02:27:06 AM
I set up the casting in my old round column mill drill this afternoon and found it tricky to start the bore with a drill, as the cylinder hole was a little deeper than the centerline of the case bore. So the bit was more than half exposed. But I got it done.

Also spent some time trying to set the mill drill's height so that I didn't have to raise or lower it when changing from drill chuck to boring head, and switching between a centering drill, a couple other drill bits and and 2 boring bars. I don't have a means of keeping the head centered if I have to change the height during an operation.

I did find a height setting that worked for all -- glad I did that before starting to drill!

Boring, too, was a little hard on the old mill. if I tried to take to much off it made some unpleasant clacking sounds from the spindle. Maybe the quill slapping. This is an interrupted cut in cast iron so I just had to take it slowly, about ten thou per pass. I hadn't finished by supper time, so I decided to leave it for tomorrow.

I think next time I'd to do this type of job in my lathe. Anyway, here's where I am this evening:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/CrankcaseBoring1.jpg) 
Title: Re: Small Flash Single
Post by: Michael S. on November 28, 2022, 06:02:56 PM
I find your engine very interesting and will be very happy to follow your report.
And the housing reminds me a lot of the housing of a compressor on my diesel tractor.
So I could also build a steam engine.........

Michael
Title: Re: Small Flash Single
Post by: vtsteam on November 28, 2022, 11:27:37 PM
Very stylish looking compressor, Michael. It would make a good looking steam engine if it worked out as suitable. Compressor to steam engine conversions have been done before successfully.

Well, it was a long boring day today in a cold shop. It took over 60 passes to bring the crankcase space to size. When I mentioned a ten thou cut earlier, that was diameter. Actual DOC was only .005" without getting too much skipping  against the cylinder bore. But I did finish by supper time, so, happy to move foreward now.  :smokin2:
Title: Re: Small Flash Single
Post by: vtsteam on November 28, 2022, 11:50:27 PM
A bigger hole:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/CrankcaseBoring2.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on November 29, 2022, 02:05:44 PM
The crankcase so far. The center of the main bore was located by indicating off of the turned cylinder to keep the two aligned.  Originally, there was a small shrinkage depression on one side of the cylinder, as cast. It was turned off by offsetting the casting slightly in the lathe to reduce the amount that needed to be turned off.

The base block had been roughed in slightly oversize before turning. Final size would depend on how much offset was needed to clean up the cylinder. Now the left side of the lower block needs to be milled down to match the right.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/CrankcaseCasting4.jpg)
Title: Re: Small Flash Single
Post by: Roger B on November 29, 2022, 05:02:36 PM
Very nicely done  :praise2: Metal casting tends to scare me like big propellors do ::)
Title: Re: Small Flash Single
Post by: vtsteam on November 29, 2022, 07:56:34 PM
Roger, thanks so much.  :cheers: Molten iron deserves respect, I have to admit the adrenalin is definitely up for me whenever I turn off the fuel and blower, swing open the furnace lid and look into that still grumbling inferno -- even through a filter and with protective gear on. That never changes. But the feeling after pouring isn't just relief. I don't know how others feel, but for me it's a feeling of calm elation, if there is such a thing. Keeps me doing it.

Well, one more pattern made, and one more pour today. This is the front plate and bearing housing pattern:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/FrontPlatePattern.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on November 29, 2022, 10:25:49 PM
Three hours after pouring, the casting looks good and cuts with a file, so it's usable. Total today including making the pattern,  was six hours from cutting wood to cooled metal part. That's a record for me with iron.

(https://www.sredmond.com//srhacksaw/FlashEngine1x75/FrontPlateCasting1.jpg)

Title: Re: Small Flash Single
Post by: vtsteam on December 01, 2022, 08:57:57 PM
Cold winds outside today, even without heat it felt warmer in the shop out of them! So I chucked my new raw casting in the 4-jaw and turned just enough off of the back face to give me a flat face square to the round part:

(https://www.sredmond.com//srhacksaw/FlashEngine1x75/FrontPlateCasting2.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 01, 2022, 09:02:14 PM
That let me grip it flat against the back face of the milling vise, with the round part against the moveable jaw. I cleaned off all of the edges. None to actual size, I just wanted them clean and square to grip again in the 4-jaw:

(https://www.sredmond.com//srhacksaw/FlashEngine1x75/FrontPlateCasting5.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 01, 2022, 09:06:06 PM
Then I put it back in the lathe and went to work cleaning up the front suraces"

(https://www.sredmond.com//srhacksaw/FlashEngine1x75/FrontPlateCasting7.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 01, 2022, 09:10:00 PM
And here is the bearing housing casting cleaned up and squared off. It will need to have a register cut in the back face, and bored to fit the bearing races, which are on order, now. That's all for today. Going in the house to get warm!

(https://www.sredmond.com//srhacksaw/FlashEngine1x75/FrontPlateCasting6.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 02, 2022, 11:48:55 PM
I turned the register today. It seats in the crankcase by wiggling it a little, and when I turn it upside down it doesn't fall out. That's about as close a fit as I can make, so I'm happy!

(https://www.sredmond.com//srhacksaw/FlashEngine1x75/FrontPlateCasting8.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 03, 2022, 04:19:05 AM
I've been thinking about what  specs I'd like to achieve with this little experimental engine. I'm not trying for a racing engine, but I am building it very much like one in terms of materials and part dimensions. Just to get a handle on a plant and pumping requirements, a reasonable goal for this engine might be 3500 RPM, and as a guess a flash boiler producing 400 psi steam pressure.

Using those very off-the-cuff figures, I could gear the water pump 2 to 1 or 3 to 1, and so not need to go to a large spur gear or worm and wheel as required for full-out racing engines.

I'm just thinking about this now to help me plan the ancillary equipment needs.
Title: Re: Small Flash Single
Post by: Admiral_dk on December 03, 2022, 11:17:59 AM
They work well as Racing Engines - but I can't help wondering if the Bore/Stroke ratio isn't too oversquare for slover running  :thinking:

Interesting journey you are taking  :ThumbsUp:

Per              :cheers:    :popcorn:
Title: Re: Small Flash Single
Post by: vtsteam on December 03, 2022, 02:53:39 PM
Hi Per thanks so much!  :cheers: I have to admit I'd intended a square engine to start with but after I'd spent some time drawing and pattern making, I realized the rod would interfere with the case walls at mid stroke unless the walls could be relieved. but since I'd also tried a unitary cylinder and case, there was no way to access that area with a tool. A rookie design mistake, but well, so I am in this!

Now that I have the parts in hand, I see maybe I could have done the relieving with a Tee-slot cutter. Next time also maybe a removable cylinder. Well, woulda, shoulda, coulda.  I'm still very excited to see what happens with this one. It's becoming fun, when before I had some trepidation about starting because there seemed so many variables to work out before building an engine. Now it's just one solid thing, and I can focus on just working around that one thing.

I'm happy to have a person of your experience along for the ride. Well, all of you.  :cheers:
Title: Re: Small Flash Single
Post by: vtsteam on December 03, 2022, 03:16:37 PM
The next thing I'm thinking about is the bearings and how to be able to disassemble the crank from the bearing housing. The inner bearing is an R8 open and the outer bearing is an R6 sealed. The overhung crankshaft will have a nut on the end holding everything in place. The outer bearing can be a tight fit in the housing. But the inner one should be removable intact, because the cam lobe will be outboard of it and won't pass through the bearing.

So, I'm now thinking about how to prevent that bearing from spinning? Will tightening the shaft nut trap it adequately? But I don't want to put much side pressure on those simple ball bearings (which arrived by the way). Just enough to keep them in place. Is that enough to prevent spinning? Or should I put a set screw in from the side of the register for the bigger bearing, and just a slight dimple in the outer race to seat. I don't want to put radial pressure enough to distort the bearing either. But is there enough meat for a dimple?

That's the kind of stuff that runs through my head, when I'm trying to sleep!  :headscratch:

--Steve
Title: Re: Small Flash Single
Post by: vtsteam on December 03, 2022, 06:15:35 PM
I decided to just try it out on a spare bearing to see what it "feels" like to try dimpling it for a set screw. The bearing is actually a 6201RS not an R8 as mentioned previously, with seals removed. I measured ~0.10" in max shell thickness, though the ball grooves reduce that to about 0.075".

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/BearingStop1.jpg)

I ground a very small dimple in the outer race with a Dremel tool, and found a 1/8 x 40 set screw:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/BearingStop2.jpg)

The screw set in the dimple well, and I "feel" like this will be okay as long as no hard pressure is applied. The only purpose is to prevent rotation of the race assuming a close slip fit in the shaft housing.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/BearingStop3.jpg)
Title: Re: Small Flash Single
Post by: Admiral_dk on December 03, 2022, 07:52:07 PM
I have never build a steam Engine - just to be clear .... but there are a number of ways to secure the crank on the bearing. One of them is to have either an angle on the Crank outside the bearing (or Cam for that matter) and an equal angled 'female' that is 'Mated to' the other one with a nut. The angle bit can also sit 'loosely' on the Crank against a 'step in diameter' - again tightened with a matching opposite.
You see this methode all the time on small IC Engines for model aeroplanes - where the Prop is tigthned against the 'female part'. This way the Crank can move a tiny bit sideways in the Bearing.

You can argue that if you don't need the 'Play' - it's even easier - just let a nut (maybe Lock-Nut) hold it.

Best wishes

Per
Title: Re: Small Flash Single
Post by: vtsteam on December 04, 2022, 03:22:43 AM
Thanks Per :cheers:

I think I'm clear on how to secure the crank and retain the bearings axially. I was just thinking about securing the inner bearing circumfrentially (against spinning in the housing). That's because the inner bearing has to be a slip fit in the housing. It can't be Loctited or interference fitted because it needs to be easily removable, so the crankshaft can be disassembled.

I'm going with the set screw and dimple for that.

Today's work.... Drilling out clearance space in the front plate/bearing housing:
(https://www.sredmond.com/srhacksaw/FlashEngine1x75/FrontPlateCasting9.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 04, 2022, 03:24:32 AM
Boring the inner bearing recess:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/FrontPlateCasting10.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 04, 2022, 03:25:56 AM
Inner bearing mounted:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/FrontPlateCasting11.jpg)
Title: Re: Small Flash Single
Post by: john mills on December 04, 2022, 05:31:47 AM
normally in that case the fit should be a push fit so you can push it together by hand but not loose never seen plain  ball bearings held with a grub screw.
John   .
Title: Re: Small Flash Single
Post by: vtsteam on December 04, 2022, 02:09:32 PM
Thanks, It is a push fit.

I nevertheless was worried it might spin in place, since, there is no retainer against the outer rim. Maybe it wasn't necessary.
Title: Re: Small Flash Single
Post by: vtsteam on December 04, 2022, 02:56:46 PM
I actually still haven't put it in yet, so still thinking about this. Maybe you guys can explain.

The only thing preventing rotation with a slip fit in the housing is the axial pressure against the bearing's rim. Without a retainer, I can only increase that pressure by how tight the crankshaft pulls the whole bearing into the housing (pre-loading) -- assuming it can be tightened with a nut at the outer end of the crankshaft.

But with ordinary ball bearings, I thought that you wanted to avoid pre-loading axially -- not like tapered roller bearings or angular contact ball bearings. Is that right?

Or am I over-thinking this?
Title: Re: Small Flash Single
Post by: RReid on December 04, 2022, 03:25:47 PM
If the bearing fits in the housing with a push fit, i.e. one that requires just a bit of thumb pressure to push it into place, then friction will be more than enough to keep the outer race from spinning unless the bearings seize. But you do need to provide some way to push or pull it back out. A couple of small through holes to allow getting at it with a drift to tap it out would be one possibility.

Looks like you're having fun, keep up the good work! :ThumbsUp:
Title: Re: Small Flash Single
Post by: vtsteam on December 04, 2022, 03:39:36 PM
Thanks RReid. :cheers:

It's a slip fit, but wiggle free. I can twist the outer rim once seated, but I can't push it sideways.

Hard to explain by words this stuff! Better to make it and take a photo. But I'll try....there will be an outer ball bearing at the other end of the housing. and both bearings can be preloaded towards each other by tightening the nut at the outer end of the crank shaft.

Between the two bearings inside the tubular housing is a cam lobe which will not pass through either bearing (it is trapped between them inside the housing).

To prevent spinning I guess it could just be the preload holding the bearing in place.....  Reading all about pre-load online... :atcomputer:

So it looks like I do want some preload, even though these are just deep groove ball bearings. Not true that it applies only to tapered roller or angular contact ball bearings. I was wrong there.

So that could take care of the worry about the bearing spinning, and a set screw may not be needed.

Ahhh, ....I might put it in anyway. With the high case temps involved in flash steam, tolerances can change, and it won't hurt to have a positive lock on that bearing.  :zap:
Title: Re: Small Flash Single
Post by: vtsteam on December 05, 2022, 07:25:40 PM
Today I shortened the housing to actual length by turning off the chucking extension. Then I bored the end for the outer ball bearing set.

The plate flange around the outside is still ovesized.

Next to do is drill the flange and crankcase for mounting screws and tap the case. I can then mount the bearing housing and mark the flange for trimming.

I've done things this way throughout in order to keep the crankcase (and cylinder) bore as the machining reference, rather than trying to relate to a particular point on the crankcase through a series of measurements.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/FrontPlateCasting12.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 06, 2022, 12:35:00 AM
Spotting the flange holes in the mill.

To set up, I first edge found the crankcase sides, zeroed the axes, then put two dots of superglue on the case front and set the bearing housing flange down on it. Even in cold weather it grabbed instantly. The register ensured that the bores were aligned. Then it was just a matter of coordinate drilling:


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/FrontPlateCasting13.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 06, 2022, 12:40:42 AM
Drilling the tap size holes. After finishing this, I broke the bearing housing free again with a few taps of a brass hammer.


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/FrontPlateCasting14.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 06, 2022, 08:25:37 PM
After drilling and trimming the flange, here are the bearing housing and crankcase casting together:



(https://www.sredmond.com/srhacksaw/FlashEngine1x75/CrankcaseCasting5.jpg)
Title: Re: Small Flash Single
Post by: RReid on December 06, 2022, 08:27:47 PM
Coming along nicely. :ThumbsUp:
Title: Re: Small Flash Single
Post by: vtsteam on December 07, 2022, 02:19:33 PM
Thanks kindly, Ron!  :cheers:

I'm at the stage now where I'm trying to decide what to do next.....I could start on the crankshaft, but I think I need the piston and con rod done first so I can weigh them to figure out what the balance weight should be sized and shaped like. The con rod aluminum is on order, I don't think it probably should be cast -- though that would be much easiest for me to do. The ally I've ordered is a short cutoff of 2014 hex bar.

I could start on the crankcase back plate, but I want to incorporate the water pump gears in a housing there. Steel spur gears are on order. Not sure if I'm going to cast a housing, and if iron or aluminum. I'd like to have the gears in hand before deciding on the exact arrangement.

I could start on the piston, I have plenty of home cast iron stock, but the cylinder bore isn't at finished size yet. Been holding off on that until the other block work is done. I'd like to fit the piston to the bore, rather than the other way around.  Maybe I should finish the bore now, then I could start on the piston. Kinda look forward to that....

Wondering what the bore finish should be like for a flash steam engine of this type? Honed cross-hatched, like an IC engine? or polished with a lap?

I do know in either case I need big clearance, and planning on a dykes ring...

Title: Re: Small Flash Single
Post by: vtsteam on December 09, 2022, 05:59:11 PM
I realized that to start making the piston, I should first hone the cylinder to get the final diameter, but to do that, I remembered, the uniflow ports ought to be milled so the honing could clean them up. So, we're two steps back. Time to mill ports. Hmmmm, how to do that......

I don't have a rotary table or dividing head for the mill. I do have a 5C collet spinner, but holding the rectangular crankcase in that and also hand rotating it while milling just didn't seem promising. Instead, I decided to try using the lathe.

I have my 4 jaw chuck presently mounted to my lathe's face plate, and it seemed well suited to holding the square crankcase.To get the lathe ready for for dividing, I first disconnected the drive belt and power, and then I taped a paper strip around the edge of the faceplate, slicing through the paper overlap with a razor blade to make an exact length strip.

Removing it, I divided the strip into 12 equal lengths using dividers, and then drew lines across with a square so I could index 6 equal ports and 6 equal solid lands, shorter by a tool width. I colored in the port spaces with black marker line so I would be less likely to make a mistake when cutting. Then with some removable contact adhesive, I re-attached the strip to the edge of the face plate. I made a pointer from a length of brazing rod which I sharpened to a point. I attached that to a magnetic gauge base post. This was my dividing rig.

For a mill, I used my small rotary grinder as a tool post attachment with a .125" rotary metal cutting bit. To test, I made very gradual cuts in order not to overstress this admittedly delicate makeshift. I turned the faceplate by hand to make the cut. Comfortable depth of cut worked out only to about .003"/pass, so it was going to be a looong way through the .250" cylinder wall thickness.

The carbide bit I'm using also isn't ideal for the purpose, intended for aluminum. But is doing the job. I just have to go slowly. I do have proper 1/8" endmills for cast iron ordered, and they may arrive today. Maybe at the slow rate I'm going, they will be here in time to get used!

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/PortMilling3.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 09, 2022, 09:58:08 PM
...Maybe at the slow rate I'm going, they will be here in time to get used!
In fact, yup they did. The new end mills let me cut at .010" depth per pass, making things go 3 times as fast! It was still about 100 passes to finish. But finish I did by dark.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/PortsMilled.jpg)
Title: Re: Small Flash Single
Post by: Admiral_dk on December 10, 2022, 12:52:16 PM
Great Ports - I'll say that you succeded very well with those  :ThumbsUp:    :cheers:

Per
Title: Re: Small Flash Single
Post by: vtsteam on December 10, 2022, 05:20:07 PM
Thanks Per!

Now that I look at my engine in the metal, I think I ought to change a couple things. The first is a mistake I hadn't noticed before, which is that one screw hole is out of position -- I thought it was just camera distortion in the pic above, but when I looked at the block it was obvious. I don't know how I missed that before. :facepalm:  :facepalm2:

I think it's 0.1" off - I must have misread the coordinate when drilling. Darn! It's okay structurally, but it's going to bother me.

The other is I'd like to cut the exhaust space recess further down towards the main block. There's no reason it has to be tangent to those ports. And I think that space looks restrictive.

When I drew it, I was going by the examples of K.B.C's and Bob Kirtley's engines. But they have separate cylinders, and need to allow room for studs and nuts under a flange (see K.B.C' engine for sv OOYAH below). Since my engine is one piece, the exhaust expansion space can be deeper.

Also I think I was being too stingy with the depth of the groove for fitting the outer exhaust ring. No reason not to make that deeper, as well.

K.B.C's engine block:
(https://www.modelenginemaker.com/index.php?action=dlattach;topic=2760.0;attach=10113;image)
Title: Re: Small Flash Single
Post by: vtsteam on December 10, 2022, 10:44:21 PM
Exhaust space widened:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/CrankcaseCasting6.jpg)
Title: Re: Small Flash Single
Post by: Zephyrin on December 11, 2022, 08:31:35 AM
nice progress with the build...
this kind of very large port can catch piston rings during its stroke...it happened to me on a tiny 2 stroke of my design, which of course did not survive !
Title: Re: Small Flash Single
Post by: vtsteam on December 11, 2022, 03:30:16 PM
Thanks Zephyrin.  :cheers:

Well we'll just have to see what happens. This engine is a close approximation of K.B.C's and Bob Kirtley's, so I have some hope that it won't self destruct, but it's a first for me, so it is a total experiment with no backing experience.

I wonder if the number of ports might have some bearing (pardon the pun) on it? This has 6, how many did yours have? Well maybe the number is unrelated, as the old Cox .049's had only two and they didn't catch.

What might make things even riskier is that these engines of this size typically have a 3 thou piston clearance, and Dykes rings right at the crown. They tend to press outwards on the upstroke. Seems like that's a combination that would catch if anything would.  :zap:

ps. Kirtley mentions pinning the ring gap in line with one of the port lands so it won't rotate. Could your ring gap have rotated into a port position?
Title: Re: Small Flash Single
Post by: Michael S. on December 11, 2022, 06:22:23 PM
There was a company in my town that built large stationary boiler steam engines and in the variant with two cylinders as a compound steam engine, the low-pressure cylinder was a direct current cylinder with the exhaust in the middle. As with you.
So that the ends of the piston rings do not jump into the doors and then break, screws were installed to prevent them from twisting.
The picture shows an example. Even with normal single-cylinder steam engines, they built the pistons with the locking screws. Maybe you can do it like this?

Michael
Title: Re: Small Flash Single
Post by: vtsteam on December 11, 2022, 07:01:00 PM
Michael thanks for the interesting piston and ring idea. I think that might be more suitable for a larger engine, And some day I might build one, so I will remember that. This little one has only 1" bore. Kirtley used a pin on his engine. Also there will be only one ring on this engine.

My engine is modeled on K.B.C's and Kirtley's racing engines, which were featured here on this forum ten years ago, and in Model Engineer 33 years ago respectively. Kirtley at the time of the ME article had broken the 100 mph model steam racing hydroplane record. K.B.C did a great job photographing and describing his own engine for his 40 mph R/C sports boat: https://www.modelenginemaker.com/index.php?topic=2760.0 (https://www.modelenginemaker.com/index.php?topic=2760.0).

I'm closely following their examples, in all the design elements, except for the solid CI block and cylinder. My version is not going into a racing boat. It's just an experimental stationary utility engine, and it will see much lower speeds and pressures.
Title: Re: Small Flash Single
Post by: Admiral_dk on December 11, 2022, 07:35:45 PM
I'm pretty sure that the Cox Model Engines didn't use pistonrings - but that the piston where Lapped to the Cylinder ....

Every Two-Stroke above a certain cc size using Rings, have some kind of control pins that prevents the rings from turning (resulting in an end going 'Out the [Port] Window').

On the other hand - if the openings aren't vide enough (and have the right shape) it's not very likely that you will have any problems .... then again - safe and sorry are a few words that spring to mind  ;)

Per
Title: Re: Small Flash Single
Post by: vtsteam on December 11, 2022, 07:49:06 PM
You're right Per, they didn't have rings.  :facepalm: I was thinking the corner of the crown itself catching. But I'm sure that wasn't a hard corner.

I'm wondering how, with a single Dykes ("L" shaped) ring, is that pin located in the ring gap? It must be at the bottom of the cylinder groove, in the lower leg of the ring.......  :thinking:

Also with a single Dykes ring, how is compression maintained across a ring gap? Isn't there leakage through that gap?

Title: Re: Small Flash Single
Post by: vtsteam on December 11, 2022, 08:05:28 PM
Here are a couple of Dykes ring photos I've found. These seem to have a cutback in the lower leg -- which maybe is there to suit a pin -- other photos I've seen don't show that, though.

Also the second ring has a chamfered upper edge, which would seem to be less likely to catch on a port. But that would actually change exhaust timing in a Uniflow engine, I think......
Title: Re: Small Flash Single
Post by: john mills on December 11, 2022, 08:58:18 PM
did that ring have another ring with a lip which fitted in that gap and the join on the other side so the gap is covered.
when i was machining rings mainly for processing compressors , i made every form you could think off  including ones  with steps with room for pins   one set that was made was in three pieces with steps and room to have pins.
a two piece ring that was made had a part sitting up which fitted in a gap on the second part covering the gap the gaps were on opposite
sides.
john
Title: Re: Small Flash Single
Post by: vtsteam on December 12, 2022, 03:18:49 AM
John, thanks for that really interesting info  :cheers:
I'm afraid I don't know exactly how the pin and gap were done, as I haven't seen a photo or explanation. Kirtley's pin does seem to fit the bottom of the "L" as drawn in the ME article. He shows only a one piece ring. I think K.B.C did as well, but there are no pics of his piston with a ring in place.

I'm thinking now that the gap in the upper leg might close up at operating heat. The racing engines operate at very high temperature and an estimated 1500 psi and 15,000 rpm, and are designed to run at top speed only.

I might need to reduce the ring gap slightly (and maybe the piston clearance?) for a lower speed engine intended for 400 psi and lower operating temperatures in order to maintain compression. So it's going to be guess work for me.  :thinking:
Title: Re: Small Flash Single
Post by: john mills on December 12, 2022, 05:02:31 AM
with stepped rings for a pin the one step was shorter with room left for a pin.
John
Title: Re: Small Flash Single
Post by: Zephyrin on December 12, 2022, 07:56:07 AM

Quote
pinning the ring gap in line with one of the port lands so it won't rotate. Could your ring gap have rotated into a port position?

yes, the ring on this 2 stroke engine could have rotate...and he did.
I had added a bronze ring on the piston to improve a poor compression, and it worked a treat, just a coupe of minute !
impossible to dismantle without ruining the engine.

https://photos.app.goo.gl/RNqtrDjcZtqUmRxLA

now I know...I'm doing only 4 stroke engine, no ports in the cylinder wall !

Title: Re: Small Flash Single
Post by: vtsteam on December 14, 2022, 12:38:56 AM
John, pin in the bottom leg it will be, as you describe.  :cheers:

Zephyrin, so sorry to hear about that, I'm sure it was a fine looking engine!

I've been working on finishing up some long overdue additions to my lathe the last two days. Just a short break from the engine to make working on it easier. Mainly electrical. I added a tach, and built a better housing for the DC speed controller, emergency stop switch, motor stop switch and speed potentiometer. I also finished off my last three homemade tool holders. I'd been using only five (finished) of the eight steel blanks I started machining a very long time ago.

Finally, I'm thinking about making a simple (tommy bar type) rotary table, using a swivel vise base I already have. It's hard to do some things I want to on this engine without an RT. If I can build one in a day or so, I might, but I don't want to take on more of a project at this point. The engine is the priority.
Title: Re: Small Flash Single
Post by: Old School on December 14, 2022, 08:02:38 PM
An interesting read so far, I have built a similar sized engine to yours and over square mine was also in a rtp hydroplane but for the smaller 8lb class. It still holds the record for the 8lb class the governing body change the weight to 9 lb and I retired as didn’t want to build another steam plant.
My record is just under 80 mph, the theoretical revs are 10,000rpm no account taken for propeller slip.

I would recommend that your reduction for the pump should be a minimum of 4 to 1, flash steam plants need to balanced to much water wet steam or not enough everything gets to hot. My pump stroke was adjustable in 10 thou steps to get the performance I wanted. The amount of superheat of the steam turned the cylinder head blue.

They are great fun and lots of frustration as well enjoy the project.
Title: Re: Small Flash Single
Post by: vtsteam on December 14, 2022, 10:20:07 PM
Wow, great to hear from an experienced hydroplane racer, Old school!  :cartwheel: and a record holder. too! I've admired these engines for a very long time.

re, pump  ratio....I think I sent for 3 to 1 steel gears a couple weeks ago. At the time I was thinking that this engine at 4000 or so rpm, non-racing, might be using proportionately less steam, (using. P.L.A.N.) and therefore proportionately less water, but that was just quick estimation.  I could increase that gear ratio if needed ... I definitely appreciate the voice of experience!  :cheers:

I do have a couple of questions.....Old School, did you use a Dykes ring, and did you pin your ring? Was the pin simply pressed into the piston, or did you have some additional way of retaining it?

For today's work, I started making a lap:


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Lap1.jpg)

Title: Re: Small Flash Single
Post by: Old School on December 15, 2022, 12:10:03 PM
Yes I used a dykes ring ring and used a pressed in pin, it cannot come out the ring holds it in. My cylinder was bored in the lathe and finished by honing with a brake cylinder hone. The finish was a smooth cris cross pattern, this helps the ring bed in so you get a good seal, my engine has compression at the top of the stroke.
Title: Re: Small Flash Single
Post by: Roger B on December 15, 2022, 12:20:03 PM
When I was designing my two stroke diesel a maximum port opening (width?) of 25° was recommended with an unpinned ring. With pinned rings 60° was ok.

https://www.modelenginemaker.com/index.php/topic,5603.msg107565.html#msg107565

Title: Re: Small Flash Single
Post by: vtsteam on December 15, 2022, 01:32:16 PM
Thank you Old School, that makes sense about the ring edge covering the pin. I'll do the cross-hatch finish on the cylinder.

Did you expand and heat treat your ring like Chaddock or cut it oversize? I can heat treat in my furnace.

Thanks for that info Roger B.  :cheers: Mine are 43 degrees.

Title: Re: Small Flash Single
Post by: vtsteam on December 15, 2022, 05:14:04 PM
Finished the lap which just slips in the bore without tightening the setscrew. This time I made it out of an aluminum sprue from casting. Haven't tried that before, though I've made a similar one out of lead. But I'm avoiding lead now. I didn't have .010" copper sheet to make one of the really nice floating style I've seen here recently. Curious to see how aluminum works for this.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Lap2.jpg)
Title: Re: Small Flash Single
Post by: crueby on December 15, 2022, 06:00:26 PM
What kind of lapping compound will you use with it?  Very interested to see how this works...   :popcorn: :popcorn: :popcorn:
Title: Re: Small Flash Single
Post by: Old School on December 15, 2022, 06:10:28 PM
My ring was split and heat treated.
Title: Re: Small Flash Single
Post by: vtsteam on December 15, 2022, 07:48:47 PM
Thank you Crueby :cheers: I only have Permatex valve grinding compound so that's what I used. It left a very fine matte finish, which I couldn't read for cross-hatching, even though towards the end I did move the cylinder end to end rapidly while running slowly at about 100 RPM. The finish is just too fine to see any marks. A stone cylinder hone would be coarser and produce cross hatching.

The valve grinding compound was coarse enough to present a fair amount of resistance to start before tightening the Allen screw expander, so I honed a bit that way. The abrasive did break down finer as it cut, and after a minute or so the lap loosened a bit. So I stopped and I gave a very slight nudge to the screw, and added a little more compound and in a minute or two after that I was done.

I didn't find any obvious problem with aluminum as the lap. It cut as well as with a lead lap (my only experience).

As far as dimensional results -- I don't have very sensitive measuring equipment. I do have a simple telescopic gauge and that seemed to show the bore consistent top to bottom and in different positions around the bore. I'll be making some go-no go bore gauges before starting on the piston. But I have a feeling things are okay.


The aluminum lap after use. Earlier I had covered the lathe ways with paper to keep the compound off.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Lap3.jpg)


Lapping. I was turning at a very slow speed ~60-100RPM. I have a DC motor drive and it isn't very powerful at very low speed -- unlike a back geared lathe, which to me is a good thing when my hands are exposed to a sharp cornered object like this. I could probably stop the spindle by hand at this slow a speed. The motor drive also has a slow ramp up which gives a good feel at the start for how much friction there is going to be in the lap. Still, it's something to be extremely careful about. Less of a problem with just a round cylinder.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Lap4.jpg)

This is the fine matte finish after lapping. Cross hatching is impossible to read with this level of abrasive.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Lap5.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 15, 2022, 07:49:22 PM
My ring was split and heat treated.

Thanks, Old School!  :cheers:
Title: Re: Small Flash Single
Post by: Brendon M on December 16, 2022, 11:35:30 AM
I am late to the party but I just wanted to say I am impressed with the casting of iron!
Title: Re: Small Flash Single
Post by: vtsteam on December 17, 2022, 03:55:26 AM
Hi Brendon, thanks!  :cheers:

It took a lot of furnace experiments and learning time to get to be able to do that with some confidence of the outcome. Several years really.

These were pretty simple bulk stock castings. Intentionally so to avoid thin and thick sections and hence the possibility of chill. They were wasteful of material and required a lot more machining than would be necessary if I had shaped and cored them more closely to final shape. But I really wanted to get to the machining right away.

Luckygen1001 on Youtube (aka Ironman) is my iron casting mentor. I follow his methods pretty closely, though with far less skill. Well, I'm gaining on him.... :mischief:

Next engine of this type will be cored through the main case at least. Too much boring there!
Title: Re: Small Flash Single
Post by: vtsteam on December 18, 2022, 02:21:36 AM
Today I made a stepped plug gauge. The "go" land I ended up with was 0.9986" and the "no-go" 0.9997".  Since the "go" was a fairly easy slip I averaged the two as a guess at the exact diameter and rounded it to 0.999 -- I can't work to tenths anyway , and my micrometer might not be that accurate, at least in my hands! Since the goal for a piston was 3 thou under, that means I'm shooting for 0.996", finished.

Now for material....it so happens I cast a couple of round bars last summer just for the very purpose having stock on hand for making pistons and cylinders, or even tooling. These are 1-1/2" dia rough. Handy to have them now.

(https://www.sredmond.com/srhacksaw/CylinderStock20.jpg)


The iron turned very nicely, and was fine grained. I turned a section down to .0998" leaving a little for lapping later. Then center drilled it:
(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston1.jpg)

At about this point I realized I hadn't checked my original drawing dimensions since along the way the engine design had changed in small ways during the machining. Mainly I needed to to check piston length and its internal bore sizes, and wrist pin location against the current engine port locations, etc. I'd also decided to change the big end bearing size. So I basically had to redraw the piston and con rod, and that took me a couple of hours revising things. By then it was supper time, and drilling a center was as far as I got.  Tomorrow, though, I've got a drawing to work with!
Title: Re: Small Flash Single
Post by: vtsteam on December 18, 2022, 04:18:18 PM
The drawing:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/PistonDwg1.png)
Title: Re: Small Flash Single
Post by: vtsteam on December 18, 2022, 10:58:37 PM
The piston required a thin boring bar initially to clear out a 7/16 drilled hole. One was  quickly made up out of a piece of 1/4" W1 drill rod. I used a propane torch to heat the end for squashing flat with a hammer, then hardening. To quench and temper I used a cup of snow from outside the shop. I shaped the cutting edge with the small belt sander I have in  the shop, and I was good to go.

After cleaning the upper bore, the piston skirt was formed with the same bar.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston2.jpg)


Cutting the Dykes ring groove:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston4.jpg)
Title: Re: Small Flash Single
Post by: RReid on December 19, 2022, 12:22:21 AM
I'll have to try making a boring bar that way sometime. Looks like it did a fine job.
Title: Re: Small Flash Single
Post by: Brendon M on December 19, 2022, 12:26:18 PM
Indeed! I will also need to file that away.
Title: Re: Small Flash Single
Post by: vtsteam on December 20, 2022, 06:51:50 PM
Thanks guys, it's the type shown in the Gingery lathe book, which I first made twenty years ago. I've only recently got an insert bar. But it's limited in how small a bore you can do, or the shape or angles you can create in recesses, so I still make boring bars sometimes.

The Gingery book called for using your melting furnace to heat the bar. But by using a MAPP torch, now, a boring bar can be heated to cherry red, forged on the anvil surface of my bench vise, and tempered in a minute or two. Using water hardening drill rod I don't even need oil for tempering, and quenching doesn't smoke up the shop. I didn't even have water so grabbed some snow!

Well on with the piston work. I relieved the upper portion above the ring groove. This is necessary to suit the upper leg of a Dykes ring. The upper ledge is only 10 thou thick now:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston5.jpg)


It's time to lap the piston. I found a donor scrap piece of aluminum that was a little bigger than the piston diameter -- bigger would have been better, but it's what I had at hand:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/PistonLap1.jpg)


It was bored a little oversize for the piston. Using the insert bar this time...:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/PistonLap2.jpg)


And a suitable sized ring parted off:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/PistonLap3.jpg)


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/PistonLap4.jpg)


Then I split the ring and milled some flats to take an adjustment screw. The ring wasn't ideal for this -- thicker would have been better. However that would make bending/closure difficult. I was able to install and 8-32 screw in the space I had. Rather than depending on the small screw to draw the gap together I decided to use the vise as an assist when tightening the screw -- that worked without problems.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/PistonLap5.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 20, 2022, 07:03:54 PM
And here the lap is in use, again I just used valve grinding compound, and a little kerosene on the lap. I did need to come down two thou, which is a fair amount. Again, paper on the lathe ways to protect them:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston7.jpg)


Measuring, I was able to hit my target of .996". In fact, .9960 if the micrometer can be believed.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston8.jpg)


And here's the lapped piston. I'm going to leave it with the chucking piece until I drill for the wrist pin with the mill.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston9.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 29, 2022, 03:55:53 AM
I took a brief break from finishing the piston to spend time with the family for the holidays, and after  because it was just too darn cold after that last major storm, and my mill is in an unheated shop.

A very low end 3D printer arrived via Santa (aka my wife) who was actually pleased with its toy-like appearance and color... she said it looked a lot like the Easy Bake Oven she had as a kid.  :ShakeHead: 

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/DSCF0968.JPG)

Well after opening the box,  it really was tiny, weighed only a couple of pounds, and it was frankly all I really wanted in a 3D printer. To be honest I've avoided buying one for many years -- I just like working in metal, not plastic. No slight meant to those having good fun with their cool printers, it's just not my own cup of tea.

HOWEVER...... it did occur to me recently that I wanted to cast an exhaust manifold for the small flash steam engine here, and I really wanted it to be a hollow toroid in shape, with flanges, and relatively thin wall, too. Making a wooden pattern for that would admittedly be extremely difficult for me. Maybe I could do it, but it would take a lot of time, it just didn't appeal.

However, it eventually dawned on me, that I might be able to make pattern for the casting I envisioned with a 3D printer. So, principles aside, (really I have none) I decided to search for the cheapest, smallest, least expensive version I could find. After watching several videos, the one I settled on was an EasyThreed K1. Unfortunately, currently discontinued. But I liked the fact that it had a twin tower gantry, unlike the cantilevered single tower versions now current. I didn't want one of those.

A search was made, and luckily a seller on Ebay had a couple of NIB discontinued K1's available for $89, so I gave my Santa the hint, and luckily I'd been a good enough boy to eventually find it under the Christmas tree in its shoebox sized cardboard cube, nicely wrapped and ribboned.

Long story, sorry ......back to the engine build...... here are my first two official 3D prints, some rough sanded patterns for my engines exhaust manifold. I've got a bit more work to do before they are ready to cast, a  wooden boss for the exhaust outlet, filling and painting. But I think they actually came out great for an Easy Bake Oven version of a 3D printer.

I did have some adjustment to do to get the quality I wanted -- both mechanical and software wise, but it actually turns out, after tuning to be quite an accurate little thing. One part I'd spec'd for no particular reason as .143" thick, I checked with calipers and it was .146". I really didn't expect a glorified glue gun to give me 3 thou accuracy, but it did. Quite pleased!

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ExhaustManifold2.jpg)
Title: Re: Small Flash Single
Post by: crueby on December 29, 2022, 04:23:32 AM
Now you need to print her an easybake oven with it!  :Lol:


Great way to get those patterns made.
Title: Re: Small Flash Single
Post by: Kim on December 29, 2022, 06:05:11 AM
Very nice!  Are you going to do that lost-wax style (lost-PLA :)) casting with this?  Or just make a sand mold with them?

Kim
Title: Re: Small Flash Single
Post by: Zephyrin on December 29, 2022, 09:25:27 AM
I also have a 3D printer, exactly for the same reasons, to print accurate model for sand casting parts in aluminum...with limited success up to now, owing to draft angle and shrinkage.
I have to increase the printed size by 1.05 (with the printer software) to get at the end dead sized aluminum parts.

yes, the precision is amazing for the price paid for that machine, and I even print drilling jig or mounting support to machine parts with confidence...
Title: Re: Small Flash Single
Post by: vtsteam on December 29, 2022, 03:05:40 PM
 :lolb: Crueby!  Maybe some workshop elves....... bwahhahaha :mischief:

Thanks Kim! Definitely not lost PLA. I have dabbled in lost foam in the past, and just don't like the method for a one off casting other than very special usage -- one reason is the time spent on making a pattern if the pour has a problem. Each pour destroys the pattern and you have to make a new one. In the case of an Easy Bake 3D printer, time is definitely precious!

I don't see myself giving up wooden pattern making -- I enjoy that as much as any other aspect of casting. But for some very special difficult shapes -- mainly for patterns with irregular interior hollows I think my printer will be a nice addition. I think it will be handy for making core molds -- which are almost always interior hollows. That was actually the first reason I had for considering a 3d printer.

Thanks Zephyrin! Yes I did use a shrinkage and machining allowance (enough I hope!) though I didn't draft the interior vertical planes (I should have). In fact this morning I started on a third piece with 2 degrees of draft on the interior vert planes, which I hope will allow release of the greensand core if the first two don't work.

I dunno, we'll see. It's definitely a new learning process for me. But I like what EZBake is doing so far!  :cheers:
Title: Re: Small Flash Single
Post by: vtsteam on December 30, 2022, 10:14:25 PM
Here are the first two patterns finished up with filler, paint and a boss added to one (wood dowel tapered). I stopped printing the later (third) pattern with tapered inside faces about an hour into its print because realized I'd forgotten to add supports. So I decided to just cast the exhaust manifold using the original pair.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ExhaustManifold3.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on December 30, 2022, 10:34:04 PM
It was well above freezing today, so I decided to make the best of it in the afternoon and try casting the manifold pieces. I had to warm and rehydrate my greensand which had been frozen into a big block.

I used the iron furnace but switched out the waste oil burner for a small atmospheric propane burner I'd built, since this was to be an aluminum melt and oil would have been overkill.

Molding was tricky because I knew the greensand core would want to stick inside the manifold pieces, unless packed very gently. I was really careful with that. Also I had to mold the cope upside down first because these were ring shaped patterns. I added a sprue and riser pattern before ramming the cope up. Then pulled those two out, rolled it, and coped down to the manifold patterns. I put in runners, and added two slips of paper over the sprue and riser holes so they wouldn't fill with sand. Then I dusted all with parting, rammed up the drag and rolled it again.

The melt was uneventful and I let the metal heat about 5 minutes after it was fluid in order to get a little extra heat into it. These were pretty thin sections for castings and the sand was cold, so I didn't want a partial fill.

I was happily surprised to see that it all worked out for what are fairly tricky thin castings, first shot. You never know until you break the mold open. Here they are as cast:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ExhaustManifold4.jpg)
Title: Re: Small Flash Single
Post by: RReid on December 31, 2022, 12:07:13 AM
Those castings look great! Well done Steve. :ThumbsUp:
Title: Re: Small Flash Single
Post by: crueby on December 31, 2022, 12:23:52 AM
Great results from your EasyCast system! Well done!
Title: Re: Small Flash Single
Post by: vtsteam on December 31, 2022, 06:57:52 PM
Thank you Ron, and Chris!  :cheers:
Title: Re: Small Flash Single
Post by: Kim on December 31, 2022, 07:33:27 PM
Those look like great castings, Steve!
And excellent use of the E-Z-Bake printer  ;D :ThumbsUp: :popcorn:
Kim
Title: Re: Small Flash Single
Post by: vtsteam on December 31, 2022, 08:04:59 PM
Thanks Kim! I think the name E-ZBake is going to stick for this 3d printer. I like it!  :cheers:
Title: Re: Small Flash Single
Post by: vtsteam on February 15, 2023, 04:39:56 PM
Well after a month and a half break from this engine, I'd like to get back moving on it. I've read a few more thi ngs about making rings, and now have less confidence than I did! But I'll try cutting some experimental rings this afternoon, to see how it goes.  :thinking:
Title: Re: Small Flash Single
Post by: RReid on February 15, 2023, 04:44:34 PM
Glad you're able to get back to this project, Steve. Looking forward to the continued progress. Best of luck on the rings! :ThumbsUp:
Title: Re: Small Flash Single
Post by: vtsteam on February 15, 2023, 06:23:55 PM
Thanks Ron. I have some concern that I made the ring groove too deep (.052"). I assumed a ring of .050" thickness, but I now think I should have made the groove 0.42"deep  and the rings should be .040" thick. This is for a ~1" d. piston. The problem was, I was looking too closely at the Pisces engine ring specs, forgetting it was a 1.1875" bore, not 1" like mine.

The main problem with what I've done will probably show up as an inability to get the rings on without breaking them.

I was originally going to bore the piston for the wrist pin, then remove from its chucking piece and then bore out the inner waste before making rings. But with present doubts, I'm going to try rings first in case I have to make another piston.
Title: Re: Small Flash Single
Post by: vtsteam on February 15, 2023, 09:57:34 PM
I spent a fair amount of time on tooling this afternoon, finished off a roughed out QCT holder I'd had lying around, and ground an HSS lathe tool to mount in it ....this one meant for trepanning a Dyke's ring's inner face. It was getting late but I wanted to try it out so I just chucked a rod of cast iron scrap, a little larger than my piston to try out the tool and holder, and just cut one by eye. I did manage to cut a ring shaped piece of metal, but that's about it! I wouldn't call it a piston ring.  :Lol:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/TrialRing.jpg)

There was a fair amount of chatter, whose source I'll have to locate. I was able to turn the piece as slow as 30 rpm with the DC treadmill motor setup, and that helped. Most of the chatter was confined to the inner face of the Dykes ring. The outer edge, bore and parted edge looked better.

Because it wasn't cut to any measurements, the ring itself is much wider and thicker than what will be needed. I think making a ring actual size tomorrow will reduce the chatter problem. On this first experiment the land was wider than actually needed. If I bore my stock first, the width of cutting face will be about half of what it was today, which in itself might eliminate the chatter.

There was also quite a large rough burr on the ID from parting off. I can probably get rid of that by boring to ID first and grinding and angling the face of my parting tool so it cuts off a ring on an acute corner edge, rather than parting square across, as it does now.

So, even though my "ring" today was nothing to write home about, it did provide some good direction for tool grinding and process change for a better attempt tomorrow.
Title: Re: Small Flash Single
Post by: vtsteam on February 16, 2023, 03:02:43 PM
Here is what the finished ring should dimension out to. The cylinder bore is presently honed to .999" so the ring shown is also .999"


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/FinishedRing.png)

My question now is what dimensions should I make the ring before splitting and heat treatment?  I imagine heat treatment will create some scale and will require some cleanup.  I haven't seen any clear recommendations, other than one mention by Chaddock of a 1 to 2 thou cleanup.

I will be using Chaddock's method of heat treating after splitting the ring by snapping it. Chaddock inserts a gag piece in the gap, sized to 4 times the ring thickness, in this case thickness is .050", so gag piece would be .200". Then heat treatment to cherry red. No mention of cooling rate, No mention of whether we're shooting for an annealed condition either. Or whether post annealing is an advantage.

As mentioned earlier, I probably should have gone with a ring .040" instead of .050" so we'll see how difficult it is to get onto the piston.

I don't know if it would be acceptable to make a ring .040" for this piston since the ring groove was turned for a .050" ring. A .040 thick ring on this piston would result in 12 thou of radial clearance vs the intended 2 thou. ( .024" diametral clearance vs . .004"). My guess is it would require a new piston to be made, but I don't know how important inner diameter clearance is.

As far as overall ring dimensions go, I think I'm going to first try cutting a ring OD of .101" giving 2 thou oversize for the bore, and hope that's the enough for clean up after heat treatment, but not too much. I think I will leave the inner diameters as drawn and see what happens. Fairly likely the first attempt will show the need for some adjustment.
Title: Re: Small Flash Single
Post by: John Roberts on February 16, 2023, 08:02:59 PM
I would prefer to force the snapped rings onto a mandrel which gives the same gap. Clamp them together with washers, nut and bolt.
 The rings to my way of thinking will stay rounder after the heat process than wedging then open.
 2 thou clean up is about right.
Title: Re: Small Flash Single
Post by: vtsteam on February 16, 2023, 11:11:08 PM
Thanks John!  :cheers:

I actually made the rings before I saw your suggestion.

First try: I cut the ring blank 2 thou oversize in diameter and bored it to finish ID. I did increase depths by 2 thou. Here I'm parting the first one off:


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Ring1.jpg)

Title: Re: Small Flash Single
Post by: vtsteam on February 16, 2023, 11:50:25 PM
To split the ring, I decided to try notching the inner lip with a needle file. I thought it might break more cleanly that way, since its cross section was "L" shaped. Since this will be a pinned ring, there will need to be a notch there, anyway:


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Ring2.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on February 16, 2023, 11:52:17 PM
To wedge the split open, I needed a tapered mandrel. I was going to make one, but then spied a #2 Morse taper dead center for my lathe. It was a perfect fit.


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Ring3.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on February 17, 2023, 12:08:20 AM
I set the mandrel in my partially opened vise, nose up, with the ring resting on the jaws, and gently tapped the top with a soft hammer. There was a soft "pop" but the ring split not where I'd filed the notch, but diametrically opposite it!   :facepalm:

Best laid plans....... well I decided to keep going with this ring, just to see if there were any other problems down the road, before scrapping it. The first one came fairly quickly as I tried to wedge a flat nut in the gap as a gag piece before heat treating. The ring broke, this time where it should have, at the notch. That was predictable because it was also the the location of highest stress since the gap was opposite.

No problem, I'd turned plenty of stock....on to Ring #2:

II turned and parted off a new ring, and this time decided not to notch it before splitting. I'd just let the ring decide where to do that. Splitting went easily, and I noticed the split was more even and square this time. Looked good. And instead of trying to pry the edges apart to insert a gag piece, I slid an old flat screwdriver into the gap, slowly, like a wedge until I had the correct gap.

This turned out to be a handy holder I could clamp in the vise, for heating the ring. I arranged a firebrick behind the ring to reflect the heat of the torch for a more even treatment. I turned down the lights and rapidly played a mapp torch around the ring from about 8 inches away, making sure to heat evenly. Gradually the color came up and when it reached an even cherry red all around, I gave it about  30 seconds at that temperature before turning off the torch.

Letting the ring cool didn't take long, and this is what it looked like after the heat treatment:


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Ring4.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on February 17, 2023, 12:38:46 AM
Ring #2 really looked the part, except for some small chatter marks on the flat face of the inner lip. But would it fit over the piston without breaking? As mentioned before, this part according to Chaddock's formula should probably have been .040" thick, but I'd made it .050".

I tried stretching it over the piston, and lo and behold, no problem, I was able to slide it down to the ring groove, and back off. I then checked to see if I could fit it in the bore, but nope, and of course it was 2 thou to large when cut. No surprise there. It was also 2 thou thicker than design.

So I spent a fair amount of time lapping the thickness down, cleaning up the outside and inside burrs, and I filed the gap a bit. Eventually I was able to just fit it in the bore. I was gratified to see no light around the ring when I sighted down the bore. It was a really close fit. Also the gap was closed tight.

I worked on this ring a while more and then tried it again on the piston. While the ring needed to be tightly closed to fit the bore, I couldn't bring the ends together when located in the groove. This turned out to be a result of over sizing things  thinking that there needed to be an clean-up allowance after heat treating.

In fact, it seemed that these rings did not need an allowance at all. Oxidation scale was merely a discoloration, with no discernible thickness or diametral loss. With the second ring, it would have been very difficult to rduce inside dimensions now, though it was probably doable with patience.

Instead I decided to turn down the rest of my blank OD to the actual cylinder bore size, and make a third ring. I also altered the edge of the HSS trepanning tool I'd ground earlier for making these rings. I flattened the front rake since it seemed too much for cast iron, and I very slightly angled the outside corner. This change, in combination with a faster feed rate at 60 rpm eliminated the chatter I'd had before.

The third ring fit the bore right after heat treatment, and also fit into the piston groove. It needs a little cleanup of burrs, and a little more gap, since I don't think a tight gap is a good idea. But this one looks like a keeper. There is no daylight in its fit to the cylinder.

Third ring unfinished and uncompressed, but it fits the piston's groove. Piston is upside down in this photo, and will be parted off after the wrist pin bore is finished. The piston crown will be flush with the ring, and is relieved above the groove to suit the upper leg of the ring's "L" shape:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Ring5.jpg)

Third ring compressed in the cylinder. Perfect fit all around. The gap is closed here, and needs some relief. The top of the Dyke ring is only .025" thick. The base is .050"


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Ring6.jpg)


All in all I'm very pleased wth the outcome, and rings have turned out to be much less intimidating to make than I thought. Dyke rings seemed even more daunting, but turned out to be relatively straightforward to make, once I had the procedure down.
Title: Re: Small Flash Single
Post by: RReid on February 17, 2023, 12:48:08 AM
Ain't it grand when things go more easily than expected?  :ThumbsUp: :cheers:
Title: Re: Small Flash Single
Post by: vtsteam on February 17, 2023, 01:07:55 AM
Yes sir Ron!  :cheers:

Maybe I should explain why I heat treated the way I did -- okay so here's the theory for heat treating with a gag piece, as expressed by Dennis Chaddock about 1967 in ME. The crucial point is that by using a gag piece and NOT trying to make the ring round when expanding before heat treating, it will go back to round when compressed.

Basically that's because we are reversing the uneven stresses created by bending a ring with a gap in it. Those stresses are pretty much the same in magnitude and location whether expanding or compressing, though opposite in direction.

So by expanding a true circular ring, we get a non-circular "C" shape, but if we freeze that shape, and then re-compress it, it will return to a circle, because we have mirrored and reversed the uneven stresses. Likewise, that ring will apply a relatively even force around its periphery.

This would explain why sometimes when people try to make the expanded shape truly circular after heat treatment, the compressed shape no longer fits the bore properly, depending on their method.

There is apparently a well-known extensive treatise on the mathematics of the shapes involved. And it gives formulas for machining a non-circular shape which, when compressed, will be become truly circular. But that seems to me the hard way to go about it. I like Chaddock's simpler method. And it seems to work. Fingers crossed.......




Title: Re: Small Flash Single
Post by: Kim on February 17, 2023, 05:26:45 AM
Well done on the rings there, Steve!    :popcorn: :ThumbsUp:

Though no direct experience myself with making rings, it seems that they can be quite the tricky business.  Congrats!

Kim
Title: Re: Small Flash Single
Post by: vtsteam on February 18, 2023, 09:03:07 PM
Thanks so much Kim. I feel a lot more confident about making them now. I actually made two more, since with the stock set up in the lathe and the procedure down, it took only about 20 minutes to cut, part, split and heat treat the extra pair.

The two next questions in my mind are, how best to bore the wrist pin hole to size in the piston , and just how to position the ring stop pin in the piston groove.

The wrist pin will be made from ground silver steel drill rod .250". Piston is .999" dia. I'm wondering how everybody else does this.... milling cutter for a flat, then center drill, then drill slightly undersize, and finally an oversize reamer....? I do have a .2510 reamer.

Second question..... here are the configurations I've been thinking about for the ring retaining pin. The groove is .063" tall for the dyke ring -- only the bottom leg of the "L" shape fits in the groove. I figure 16 ga. pin would fill the groove. It could either be located centered in the groove, or centered on the bottom lip of the groove (harder to do).

It could also extend out from the groove the full width of the ring, or stop short of that. I do have some question about how the pin is retained. I assume we don't want it rubbing against the cylinder wall. Here are a few of the possible arrangements:

(note flush with cylinder below should say flush with piston...)

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/PinLocations.png)


 
Title: Re: Small Flash Single
Post by: RReid on February 19, 2023, 12:30:11 AM
Quote
milling cutter for a flat, then center drill, then drill slightly undersize, and finally an oversize reamer....?
I have not done a flat for the pistons I've made, just carefully center drilled. Then drill slightly under and ream, with a std on-size reamer (in my case usually 3/16" drill rod and 3/16" reamer). 

PS - Oh, but I do it all on the nice rigid mill, not the drill press.
Title: Re: Small Flash Single
Post by: vtsteam on February 19, 2023, 03:34:22 AM
Thanks Ron!  :cheers: Do you think 1 thou over reamer is maybe too much? I don't have a .250 reamer. I guess I could make one, if it's better to go on size for a wrist pin.
Title: Re: Small Flash Single
Post by: Roger B on February 19, 2023, 07:49:20 AM
Looks good  :ThumbsUp:  :ThumbsUp:

There are many variations on ring making, you seem to have found one that suits you  :)
Title: Re: Small Flash Single
Post by: RReid on February 19, 2023, 03:19:59 PM
Quote
Do you think 1 thou over reamer is maybe too much?
I don't know, really, but I feel that it may be a bit sloppy, especially if the con rod end is the same amount over. Sometimes a tired drill bit will give a hole just the right amount of "tight" if used like a reamer through a pre-drilled hole (requires an experiment on scrap). Or how about making a D-bit reamer from the rod stock the pin will be made from? Ideally, I try to make my wrist pins be a good sliding fit into the rod end, but a thumb-press fit into the piston. Not that this ideal is always achieved! Caveat: I have no experience with cast iron pistons.
Title: Re: Small Flash Single
Post by: vtsteam on February 19, 2023, 03:48:37 PM
Thanks Roger, and thanks Ron  :cheers:

I'm new to the clearances needed on engine parts Like model wrist pins, so the voice of experience helps. I'll make a reamer from the drill rod -- I've done that before, Just to make sure I'll try it out first on another piece of the same cast iron, and also try a hole made with the .251 reamer. See what happens.... :cheers:

For the ring retaining pin, I think I'm going to go with a pin length that is not exposed -- just sits in the lower leg of the L shape, but not through it all the way into the vertical leg. And it will be centered in the ring groove. Even if the pin comes loose it can't contact the cylinder wall, and also the ring seal will be better.

I think I understand now how to complete the piston.
Title: Re: Small Flash Single
Post by: vtsteam on February 19, 2023, 04:27:50 PM
Oops, no, one more question.....where on the piston to put the ring locating pin?

It will need to be in line with the lands between the 6 exhaust ports. Two of those lands are inline with the wrist pin orientation, ie. at the front and back of the cylinder. The other 4 lands are at 60, 120, 240, and 300 degrees from the front of the cylinder.

Since the ring is pinned it can't rotate. Is there an advantage or disadvantage to locating it inline with the wrist pin orientation?

Most sources online that I've found discuss multiple ringed IC 4-stroke pistons, and conclude that rings rotate anyway in use. So no help there.....
Title: Re: Small Flash Single
Post by: Admiral_dk on February 19, 2023, 06:02:21 PM
Like you I prefer the last sketch solution for the lock-pin. This way the ring can't rotate and the pin can't make contact with the Cylinder  :ThumbsUp:

I have yet to see a Two-Stroke Piston with one off those pins located next to the Wrist-Pin/Piston-Pin ....
There is almost always a Port there and it would be an extra stress-point next to the Piston-Pin -> more prone to damage ....  :wallbang:

So any of the four remaining positions should work fine  :cheers:

Per
Title: Re: Small Flash Single
Post by: Niels Abildgaard on February 19, 2023, 06:27:18 PM
Thanks so much Kim. I feel a lot more confident about making them now. I actually made two more, since with the stock set up in the lathe and the procedure down, it took only about 20 minutes to cut, part, split and heat treat the extra pair.

The two next questions in my mind are, how best to bore the wrist pin hole to size in the piston , and just how to position the ring stop pin in the piston groove.

The wrist pin will be made from ground silver steel drill rod .250". Piston is .999" dia. I'm wondering how everybody else does this.... milling cutter for a flat, then center drill, then drill slightly undersize, and finally an oversize reamer....? I do have a .2510 reamer.

Second question..... here are the configurations I've been thinking about for the ring retaining pin. The groove is .063" tall for the dyke ring -- only the bottom leg of the "L" shape fits in the groove. I figure 16 ga. pin would fill the groove. It could either be located centered in the groove, or centered on the bottom lip of the groove (harder to do).

It could also extend out from the groove the full width of the ring, or stop short of that. I do have some question about how the pin is retained. I assume we don't want it rubbing against the cylinder wall. Here are a few of the possible arrangements:

(note flush with cylinder below should say flush with piston...)

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/PinLocations.png)

Prof Blair of Two stroke fame claimed that if the ports in cylinder were less than 30 degree, ring fixing is unnessecary.
Title: Re: Small Flash Single
Post by: vtsteam on February 19, 2023, 08:31:08 PM
Thanks Per, I'll keep that in mind.  :cheers: 

Niels, thanks. Roger B's information said 25 degrees, but in any case my ports are 43 degrees so definitely in need of a pin. :cheers:
Title: Re: Small Flash Single
Post by: vtsteam on February 20, 2023, 11:33:06 PM
I tried a few different drill and reamer combinations on some scrap today for drilling the wrist pin bore in the piston. I made a toolmaker's reamer from the .250" drill rod (silver steel) I'll be using as the wrist pin, and also had on hand a .251" reamer.

Both seemed to me to produce an easy sliding fit, so I then tried a .249" reamer, and that gave a closer fit. I could push the pin in with my fingers, but there was some resistance. I don't know if the reamers are off-size, or the drill rod is, but anyway, I was able to find the fit I wanted. So then on to the mill with the actual piston, and after lining up, the bore job was done successfully.

Now on to the ring locating pin. I'm taking Per's suggestion to drill that one at 60 degrees off of the wrist pin axis.

I need to do some tests for this, too. The ring groove is .067" I have a .063 drill, I'll probably turn the pin from a stainless steel screw, and it should be an interference fit in the hole that the drill bit leaves, whatever that is. I think the only way to tell is to try again on scrap. It also has to be just the right length to bottom out in the piston and stop inside the ring lower leg.
Title: Re: Small Flash Single
Post by: vtsteam on February 27, 2023, 11:01:17 PM
I drilled the ring pin locating hole today .0625" , 300 degrees from the front of the piston:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston11.jpg)


To make the pin I turned down a stainless steel socket head cap screw to .0630"

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston12.jpg)



And pressed it into the piston. The bury was .125, and the stick out was .030", which is the depth of the horizontal leg of the L shaped ring, flush with the inside of the upright leg.

You can see that the upper part of the piston is relieved above (to the left in the photo) the ring groove to accommodate the outer part of the ring. The piston will be parted off .067" above the ring groove.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston10.jpg)
Title: Re: Small Flash Single
Post by: RReid on February 27, 2023, 11:53:35 PM
Lookin' good, Steve. :ThumbsUp: :cheers:
Title: Re: Small Flash Single
Post by: Admiral_dk on February 28, 2023, 10:08:32 AM
Looks like you executed that very nicely  :ThumbsUp:

Per  :cheers:
Title: Re: Small Flash Single
Post by: vtsteam on February 28, 2023, 03:54:27 PM
Thanks Ron and Per!  :cheers: :cheers:

The stepped piston, Dyke ring, and locating pin were the most unfamiliar and worrisome parts of the construction, so I took a long time thinking about every little step. I feel relief at getting through that. The only tricky part left to do is notching the horizontal leg of the ring to fit the pin. That will take some thought.

I need to grip it so the delicate springy ring doesn't break while grinding the inside leg with a Dremel tool, or file, and taking off .033" from either side of the gap, while not nicking the upright rim leg. I think I'm going to have to make some kind of clamping jig up, that leaves the ID clear for a tool.

But while cogitating on that, I'm going to move on with other parts of the engine. Just let the ring gap problem set in the back of my mind.
Title: Re: Small Flash Single
Post by: Kim on February 28, 2023, 05:26:12 PM
Lots of little fiddly stuff with that piston!  :popcorn:
I'm sure you'll get it figured, Steve.

Kim
Title: Re: Small Flash Single
Post by: Admiral_dk on February 28, 2023, 05:46:26 PM
If you havent 'Broken the Ring' yet - you can use a small diameter End-Mill on the inside and follow up with a small File ....
And if broken - I would consider making a small jig that can hold and support the Ring while Filing ....

My two Cents - for what ever they are worth ....  :old:

Per          :cheers:
Title: Re: Small Flash Single
Post by: vtsteam on February 28, 2023, 07:37:27 PM
Thanks Kim and Per!  :cheers: :cheers:

Yes, Per the ring was broken and tested in the bore with the piston, before the pin was added, so all that is needed now is the pin clearance gap.

I've snapped three rings so far getting them on and off, and this is the last of my machined stock, so I'm being extra cautious with this one. I won't put it back on the piston until I've parted the piston off. That will make putting the ring on much easier, because the top of the piston is relieved. I can then slip it on over the top.

So, I'm going to have to think of a clamping fixture to make the pin clearance slot in the ring, as you say.

I have a small air cooled high speed milling spindle coming, and I may be adapting that to both my lathe and mill as an accessory -- it may be the solution to doing the slot accurately after I make a jig to hold the ring.
Title: Re: Small Flash Single
Post by: vtsteam on March 02, 2023, 08:22:16 PM
The piston parted off:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston13.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on March 06, 2023, 06:52:40 PM
Just catching up on this engine.....

Piston and Ring: I was able to notch the horizontal leg of the piston ring with a .040" diamond burr in my Dremel, and a clean up of the corners with a needle file. It now fits the ring locating pin.

The ring slips fairly easily over the piston crown now because of its reduced diameter, and the very short distance it needs to slide to seat.

Connecting Rod: I milled down a 2-3/4" long piece of my 1" 2014 aluminum hex bar stock to a rectangular blank for the connecting rod.

Crank Pin and Big End Bearings: I'd received earlier some no-name 3/8" SCE66 drawn cup needle roller bearings and 12 inches of  3/8" Thomson 60 Case Quick Shaft -- ground and hardened linear shafting, which I'd intended to use for the crank pin.

But no go. The bearings were a sloppy fit on the shaft. To check, I turned the end of a piece of scrap rod as a gauge to fit the bearings closely, and found that actually measured ~0.3773". A check of the shaft measured 0.3739". So about a three thou mismatch.

The cause was my fault for not checking the tolerance ranges. The shaft I had was a Thomson Type L shaft, intentionally undersized a thou, and I should have looked for a type N shaft which has tolerance range close to .3750", intended for needle bearings.

No tolerance was actually given for the bearings which were just generic 3/8"on Amazon, so that shouldn't have been a surprise. I've since then ordered an INA branded SCE66 bearing -- according to specs: .3750" but we'll see what actually arrives.

I then tried to order some Thomson type N .375" shaft direct from the company, as it is rarer than the L type and not easily found elsewhere. Their order website was difficult to sign up for, with Microsoft apparently doing user verification by emailed codes, which went into spam for me, once, then didn't work, then was repeated, etc. but eventually I got through. I finally got 10" of material in my cart at $11, but then after all the rigamarole, they tacked on $20 for UPS ground shipping, and I got irritated so canceled the whole deal.

So, what to do...... well I do have 3/8" W1 water hardening drill rod, which I've checked at .3753". It's not hardened, so hardening and cleanup will likely change that. If finally undersized, I could instead turn some 1/2" drill rod down close, harden, temper and lap it to whatever is needed by the INA bearing.

I imagine it's possible that linear shaft might be better material for this purpose, but the crankpin is well oversized in my engine for the need, so may not be a problem. It sure would have been nice, though, to just cut a length of linear shaft and use it directly rather than going the homemade route.

As for progress..I'm going to wait to drill the bearing holes in my con rod blank until I have the new bearing, and know for sure its dimensions, since it needs a press fit. So we're on pause here.

Here are the various bits mentioned so far. Left to right Thomson Linear shaft and a bearing mounted, 3/8" drill rod and bearing, test pin that I turned and bearing, Piston with ring mounted, 2014 aluminum hex bar and the Con rod blank.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod1.jpg)

 
Title: Re: Small Flash Single
Post by: Roger B on March 06, 2023, 08:06:15 PM
Nice work on the piston and ring  :praise2:  :praise2: Tolerances are fun  ::)
Title: Re: Small Flash Single
Post by: RReid on March 06, 2023, 08:19:36 PM
Have you tried McMaster-Carr? I always find them and their website easy to deal with. This hardened O1 drill rod might work for you, but will be a little bit more expensive. I usually pay under $10 for shipping from them, as long as the entire order comes from the same warehouse.
https://www.mcmaster.com/products/~/hardened-tight-tolerance-multipurpose-oil-hardening-o1-tool-steel-rods/?s=high+precision+drill+rod
Title: Re: Small Flash Single
Post by: vtsteam on March 07, 2023, 12:01:09 AM
Hi Roger, Ron, thanks!

Ron, since I already have the W1 rod on hand, and McMaster would be in the $30 range, I guess I'll try what I have on hand....

HOWEVER..... the INA bearing just arrived, and it's worse than the ones I already had. Worse meaning oversized compared to the test pin I made fitting the others. It therefore means it is greater than .377" -- the test pin size. I've checked my micrometer against Pratt & Whitney gage blocks just now and it's right on the money.

I'm attaching the INA (Schaeffler) SCE66 bearing Datasheet. They have the specs in metric, and it claims the ID is 9.525 mm -- that's 4 significant figures yet the actual bearings I have are about 9.576 mm.

So, what is going on? Is it possible the bearings are oversized on purpose so that pressing them in brings them to the supposed .375" ?

But that's a huge reduction isn't it? about 2-1/2 to 3 thou interference fit on a bearing OD of .5645 (also larger than the 9/16" OD claimed)..... Is that right????  Squeeze them in, and all will be well?

Advice please.
Title: Re: Small Flash Single
Post by: vtsteam on March 07, 2023, 12:32:51 AM
SKF Bearings has some online info about mounting and tolerances for their own bearings. From what I can gather about their drawn cup needle roller bearings of 10 mm (close enough to my size)

1.) the tolerance should be measured by pressing into a ring gauge .020 mm less than the OD of the bearing
2.) the resulting bore should be +31 micrometers compared to nominal.

So working that out for my inch INA and no-name bearings, if similar,

1.) I'd press with a .0008" interference fit (much more reasonable),
2.) and expect a tolerance of about +.0012".

If I add those two together I get +.002" -- which is what I'm guessing they should measure, more or less, in the unmounted state.

I guess that's close for the no-name bearings. Not sure why the Schaeffler INA bearing is looser. It does look like a better bearing, with more rollers and a heavier cage.

Maybe I'm over thinking this, and needle roller bearings are expected to be looser when mounted than I imagined...  :shrug:
Title: Re: Small Flash Single
Post by: vtsteam on March 07, 2023, 01:07:56 AM
More study of this problem. Here's a chart of Running fits of the RC5 and RC6 class, which I'm guessing is similar to what I'm doing. These are probably meant for solid bearings and shafts, but should give me some ballpark understanding of what to expect for rollers.

If I look fo the ranges for shafts and bearings  of .375" (the brown line), The standard tolerance limit for a hole in an RC6 fit  is up to 1.4 thou. That agrees with the 1.2 figure quoted in the SKF bearing info. That would be after pressing the bearing into its housing.

Permissible with that would be a shaft 1 thou under, which would give a total clearance of 2.2 thou  -- easily within RC6 requirements -- and actually also fitting an RC5, except for the slightly larger than expected hole.

If this is all applicable, then I may actually be able to use the linear shaft I have.

BUT.....is it applicable?
Title: Re: Small Flash Single
Post by: vtsteam on March 07, 2023, 03:14:17 AM
I feel like I'm talking to myself.... well I am....sorry about the serial posts.  I don't think the last post is applicable. By definition, a shaft and hole plain bearing is a skidding mechanism. A roller should not be. It seems to me to need a closer fit.

Will wait to hear from someone knowledgeable here....
Title: Re: Small Flash Single
Post by: Admiral_dk on March 07, 2023, 09:22:10 AM
Hi Steve

You are not talking to yourself (though not many opened the last chart) ....
But as I for instance only have changed bad bearings, with new of same size - I haven't had to worry much about this ....

I have actually constructed some parts with bearings - but as none of those has been build - still no experience  :-[

I too hope that someone with experience will provide an answer - or at least tell a bit about what they experienced.

I must admit that I would not expect that a slight compression of the outside of the bearing will result in a smaller hole on the inside part - simply because it implies a big load on the Balls / Rollers.

Per            :cheers:
Title: Re: Small Flash Single
Post by: uuu on March 07, 2023, 10:55:08 AM
I've never measured it, or worried about coded tolerances, but have found that roller bearings as supplied are way too loose on the shaft (or hardened inner sleeve).  Once pressed into the housing, they seem to fit OK.

Wilf
Title: Re: Small Flash Single
Post by: vtsteam on March 07, 2023, 01:38:52 PM
Thanks Per, and Wilf. I did some more research this morning and read what I could about it in Machinery's Handbook. I unfortunately only have a 1967 Edition.

It's difficult to weed through all of the tolerance information, and I believe available sizes of needle roller bearings have come down since the 60's, and standards have changed as well.

I did gather that one should expect a reduction of shaft size of 80% of the reduction due to an interference fit in  the housing.

I also think that for bearings of the time, the expectation was that nominal sizes for the OD of the bearing and the shaft were controlling, and that tolerances were based on what was acceptable outside of those exact nominal figures. Those tolerances were quite small, and looked to be a matter of tenths of thous.

Since the nominal dimensions of my SCE66 bearings are 3/8" for the shaft and 9/16" for the housing, I think the only thing to do is try an installation in a piece of aluminum scrap using the 9/16" (.5625") dimension as accurately as possible. See what the resulting fit is on the drill rod, which is as close as I can come to .3750" presently.

This means a rather severe interference fit, since the bearing itself measures ~.5644 OD.

This is in line with what you were suggesting, Wilf.
Title: Re: Small Flash Single
Post by: uuu on March 07, 2023, 05:22:00 PM
I did find, on the SKF website, their "dolly" design, used for pressing the bearing into it's housing.  Not that I've ever made one - just a shouldered rod does it for me, with the minor diameter sufficiently below the nominal inner size, so it doesn't get trapped.

https://cdn.skfmediahub.skf.com/api/public/0901d19680578258/png_highpreview_800/0901d19680578258_png_highpreview_800.png (https://cdn.skfmediahub.skf.com/api/public/0901d19680578258/png_highpreview_800/0901d19680578258_png_highpreview_800.png)

Wilf
Title: Re: Small Flash Single
Post by: RReid on March 07, 2023, 06:01:28 PM
Quote
I did some more research this morning and read what I could about it in Machinery's Handbook. I unfortunately only have a 1967 Edition.
Sorry, I have no advice to offer, and my 1920 edition of Machinery's Handbook doesn't either.
Title: Re: Small Flash Single
Post by: internal_fire on March 07, 2023, 06:23:06 PM
Sorry, I have no advice to offer, and my 1920 edition of Machinery's Handbook doesn't either.

Was that the version printed on papyrus?  :)

Gene
Title: Re: Small Flash Single
Post by: RReid on March 07, 2023, 08:17:56 PM
Yeah, that's the one. :Lol:
Title: Re: Small Flash Single
Post by: vtsteam on March 08, 2023, 02:41:21 AM
Thanks for replying Wilf, Ron, Gene.

Wilf, I saw that pressing tool on the SK website. I didn't get too complicated with mine but I did put a 15 degree angle on the pressing part -- that's mainly to put pressure on the outer rim of the bearing housing, which has a slight radius, and keep pressure off of the middle.

Here's a pic of a test bearing mounted in a scrap piece of aluminum, one of the needle bearings, and the pilot I used for pressing the bearing in place.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/BearingTest1.jpg)

I bored the scrap aluminum out to .5625", checked with a telescopic bore gage and micrometer. I'm a little unsure about that however, as the particular scrap did not machine well. I turned up the pilot from some .75" dia. steel cold rolled steel. The pin was a loose slip fit in the bearing bore so it wouldn't get grabbed if the bore reduced.

As mentioned above, the pressing face tapered in toward the center 15 degrees, and the bearing was inserted with the printed face up.

When pressing I expected a lot of resistance, since the bearing was a couple thou oversized. but I didn't find that. It pressed fairly easily and smoothly. Likewise I expected the bore to have shrunk, but it did not seem to have. The fit was not good on the .375" drill rod, while it seemed to be a good running fit on the .377" test gage I'd made a few days ago.

So, I don't know. I'm wondering if my telescopic gage housing bore measurement might have been off. I think I'm going to repeat the experiment again tomorrow, but this time I'll make a plug gage for the .5625 bore, to check it for sure, and find a piece of 6061 for the aluminum.

Anyway, that was today's fun.

My 1967 Machinerys Handbook is colored paisley, btw, and looks really psychedelic under black light!  :insane: :naughty:
Title: Re: Small Flash Single
Post by: vtsteam on March 09, 2023, 02:51:06 AM
So today I turned a go-no plug out of steel rod scrap. Go measured .5623", no-go measured .5640". Nominal dimension is 9/16 or .5625"

I carefully bored a piece of aluminum sneaking up to .5625", as measured with a bore gauge and micrometer. I checked the micrometer against a gage block and it was adjusted perfectly. The go land on the plug was a close sliding fit in the hole and the housing came up solid against the .5640" land.

I then repeated yesterday's bearing press exercise with a new bearing. Before mounting, the bearing measured .5644" on the OD, representing a .0019" interference fit. Again it pressed easily and uniformly into the bore.

When I tried the 3.750" drill rod in the bearing, it was again a sloppy fit. I then tried a 3.774" ID plug gage I'd made up earlier, and it was a reasonably close fit -- far better than the drill rod.

Conclusions:

1.) My experiment yesterday had the same result as the one today, where greater pains were taken to insure the bore was on nominal size.

2.) These bearings are at least .0024" oversized on the ID, and pressing into their nominal OD (9/16"), results in a ~.002  interference fit, but does NOT change the ID.

3.) The 2 thou interference fit in the housing is not difficult to press, and does not seem to distort the bearings, which were free running afterwards.

4.) I believe I'm going to have to make a crankpin of ~.377" diameter to fit the needle bearings I've received for my engine. I will probably use the INA Schaeffler bearing, rather than the No-name bearings, as it has more rollers and a more robust looking cage. I did not test that one by pressing into a housing, as I only had one of them. It's unmounted measurements however are the same as the no-names, and it shows just as much slop on test rods before mounting.

I'll make up a new plug gage after pressing the bearing into my engine's con rod, to get as accurate as possible an idea of the pin diameter needed to fit it properly.

It's a mystery to me why these two different mfr. SCE66 needle roller bearings are oversized, and why I can't  find a clear explanation anywhere about how this size bearing is toleranced and what acceptable final clearances are. But I'm just going to accept them as they are and work around what I've actually measured.

Below are the two test mountings that I tried and the go-nogo plug. The newest test piece is on the right.


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/BearingTest2.jpg)
Title: Re: Small Flash Single
Post by: Kim on March 09, 2023, 05:40:05 AM
Well, Steve, you've done a very careful, controlled experiment, so you've learned a lot here.  And you've brought us all along with you!  Education can be expensive. Thanks for paying the tuition for us!  ;D

Kim
Title: Re: Small Flash Single
Post by: Admiral_dk on March 09, 2023, 11:01:50 AM
Amen to Kim's sentiment + thank you  :ThumbsUp:

Per
Title: Re: Small Flash Single
Post by: vtsteam on March 10, 2023, 12:40:29 AM
Thanks Kim and Per.  :cheers: :cheers:

Glad it was of use or interest to you guys. I hope maybe eventually someone will read it here, and clear that mystery up for us. I don't like to just give up without understanding a mechanical detail, but time to move on.


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod3.jpg)


Today, I marked out the connecting rod, and thought about how to drill the bearing holes. I can bore a hole most accurately in the lathe, but then locating the small end bearing hole would require moving the part in the chuck or faceplate.

I can locate the centers of the holes most accurately on the mill, but the .5625" needle bearing hole couldn't be made with the boring head because it's a little too small. Also I don't own a 9/16" drill or reamer.

After thinking about it for awhile I remembered I had some imported adjustable reamers -- I seldom use them because they're not well made and difficult to adjust,. But they seemed the best way I had to do the job. So out of a fairly musty box they came.

I set up some scrap aluminum blanks in the lathe, drilled them 1/2" and then used the reamer and the bore gauge, adjusting a small amount each trial. If I overshot, I had to reverse the blank in the chuck and try from the other side in a fresh 1/2" hole. I went through a couple blanks, and finally got the reamer to cut .5625" after what seemed an hours long marathon.

It was late afternoon, but I really wanted to get something done on the con rod, so I took my aluminum blank and headed down the hill to the bigger (and colder) shed where the mill is located, and started coordinate drilling using my homemade bluetooth DRO.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod4.jpg)


I drilled the big end 1/2", and then reamed with the pre-set adjustable at the slowest possible mill speed, and dousing the work with WD-40.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod5.jpg)


I drilled the small end with a fresh 5/16" bit and no reamer, since I'll be pressing in a bronze bearing there and I can suit it to fit the bore.

With that the day's hole making was done!  :smokin2:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod6.jpg)







Title: Re: Small Flash Single
Post by: Kim on March 10, 2023, 12:58:31 AM
Nice progress, Steve!  :popcorn:

I have a set of those cheap adjustable reamers!  Although at the time I bought them, i didn't think they were cheap!  I thought "good tools cost good money" and figured they'd be used a lot. Not so much.  As you say, they are a pain to adjust.  But the have sure come in handy from time to time!   :embarassed:

Kim
Title: Re: Small Flash Single
Post by: Roger B on March 10, 2023, 05:28:18 PM
Your bearing problem seems a little strange  :thinking:  I know that ball races come in various clearances grades to allow for installation conditions. Maybe the same applies to needle roller bearings.

https://shop.eriks.nl/en/bearing-clearance/
Title: Re: Small Flash Single
Post by: Admiral_dk on March 10, 2023, 06:06:10 PM
In reply to Rogers link - I can only quote Marv (from the other day) - I learn something new on this forum every day  :cheers:

Per
Title: Re: Small Flash Single
Post by: vtsteam on March 10, 2023, 06:59:59 PM
Roger, thanks for that link. Very interesting.

Reading through that explanation, my guess is that C4 would be appropriate for a connecting rod. But what is C4 in say decimal inches or mm for a 3/8" (SCE66) roller bearing ? The document only says that it is "More than C3". No specific help there.

Unfortunately neither of the two bearing manufacturer's for the bearings I have provide a C rating.

So, lacking any specific information (including the mfr's suggested housing bore size for a press fit), all I can do is go by what "feels" right.

In fact I haven't found any clearance information for any SCE66 bearing by any manufacturer. Even one reference which mentioned actual recommended clearance would be helpful to better understand this type.
Title: Re: Small Flash Single
Post by: vtsteam on March 10, 2023, 08:09:53 PM
Well back in that rabbit hole, I just wrote to INA bearings asking re. SCE66:

1.) What is the recommended housing bore diameter?
2.) What is the ISO clearance rating (Cn, C3, C4....?)
3.) What is the typical unmounted OD and ID of the bearing?

I'll let you all know what their answers are if they reply.
Title: Re: Small Flash Single
Post by: Roger B on March 10, 2023, 08:15:11 PM
It's not anything I really understand, it's just something I have picked up from the mechanical technicians at work  :headscratch:
Title: Re: Small Flash Single
Post by: vtsteam on March 10, 2023, 09:11:01 PM
Well we should have an answer, Roger, from the bearing manufacturer itself.

I've found a drawing on Amazon of the bearing I ordered-- attached. It was shipped from Johnson Bearing and Supply, Inc. , Sparks, NV. The box was just a generic brown box with SCE66 written in Sharpie on it. The bearing itself is stamped INS SCE66 USA.

But the drawing is at odds with my bearing's dimensions. Dwg says OD of .563", I have .5643". Their length is .375" mine is .3715". No ID indicated.

Also only 4 rollers are shown in the drawing, and oddly, a vertical distance given between two of the four rollers?

Well, just wait and see what the company says.
Title: Re: Small Flash Single
Post by: vtsteam on March 11, 2023, 12:59:03 AM
Today I milled the con rod sides down using a couple of turned aluminum bushings as guides to make sure I milled inline with their centers.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod7.jpg)


Then I turned up a bronze bushing to fit the small end:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod8.jpg)


And press fit it into the connecting rod. I decided to drill it out before doing any rounding of the ends of the rod, so I could use the end flat as a reference in locating the wrist pin hole:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod9.jpg)


Drilled through:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod11.jpg)


And the bushing installed. I've left reaming for later.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod10.jpg)
Title: Re: Small Flash Single
Post by: RReid on March 11, 2023, 01:57:24 AM
You mark my words, that's gonna grow up to be a mighty fine conrod. :cheers:
Title: Re: Small Flash Single
Post by: vtsteam on March 11, 2023, 01:39:52 PM
Thanks Ron!  :cheers: 
Title: Re: Small Flash Single
Post by: vtsteam on March 12, 2023, 12:28:12 AM
Today I started out by radiusing the sides of the con rod big end, trimming the rod to final length and milling the sides to thin it.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod13.jpg)



By lunch time this is what it looked like:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod14.jpg)



I reamed the con rod small end to final dimension 0.251"

It was now time to start rounding the rod ends. For that I planned to set up my shop made rotary table. This would be the first use on an actual project. I was curious to see how well it would work out.

But first I needed some pilots to fit the table and con rod. So I turned the first one here .249"  to fit the small end (and other future projects).

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod15.jpg)


I ended up making three of the them: .249", .374", .561" to fit holes .250", .375", and .5625".

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod16.jpg)



I set the con rod on top of a shim and clamped it down to the new rotary table with the .561" pilot:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod17.jpg)


Milling was easy and went well:

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod18.jpg)



The con rod after milling. I need to do a little more finish work and install the needle roller bearing.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod19.jpg)
Title: Re: Small Flash Single
Post by: Kim on March 12, 2023, 04:53:01 AM
Beautiful con rod, Steve!   :popcorn:

The turn table seemed to do the job! What did you think? Are you pleased with how it worked?  Inquiring minds want to know...  ;D

Kim
Title: Re: Small Flash Single
Post by: vtsteam on March 12, 2023, 01:31:07 PM
(https://www.sredmond.com/srhacksaw/FlashEngine1x75/ConRod20.jpg)


Kim I found the table to be very quick and easy to set up and use. It is quickly clamped in the mill vise, and you can mill as fast as you crank the Y axis in and pull the Tommy bar handle. You do have to always remember not to climb mill, except on the return pass -- which seems to clean up any scratches if you have a sharp mill.

The only thing I want to change is the handle attachment, and make a shorter handle when I need to do a 360 degree mill. My handle presently hits the mill column If I try to go all the way round. necessitating a stop and the handle re-attchment in another position.

You can't do specific degrees (without adding graduations), or lock the table (without adding a brake or clamp), but that didn't present a problem in this job.

I like it -- especially the speed of setup and facility of use for this particular con rod rounding purpose.
Title: Re: Small Flash Single
Post by: Kim on March 12, 2023, 03:22:39 PM
Excellent!  Sounds like a worthwhile tool to have in your toolbox!   :ThumbsUp: :popcorn:

Kim
Title: Re: Small Flash Single
Post by: vtsteam on March 13, 2023, 02:12:21 PM
Thanks Kim, I'm feeling encouraged. It's definitely helped making this engine.  :cheers:

re. the pivot table, yesterday I made a new slightly shorter solid handle with threads on the end, so it screws more quickly into the table than the first handle, without needing a wrench. I also added the ER-40 chuck to the table. I found that some extra bolts located around the outside of the chuck actually worked, when screwed down, as clamps to keep the table from turning. So there is no need of any additional clamp.

I chucked the piston up to clean out the interior preparatory to mounting it on the connecting rod.

(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston14.jpg)
Title: Re: Small Flash Single
Post by: vtsteam on March 13, 2023, 02:14:04 PM
And tried it out with a bit of .250 drill rod as a temporary wrist pin:


(https://www.sredmond.com/srhacksaw/FlashEngine1x75/Piston15.jpg)
Title: Re: Small Flash Single
Post by: Admiral_dk on March 13, 2023, 07:54:27 PM
Nice looking parts and great result from the newly made Tool  :ThumbsUp:

Per    :cheers:
Title: Re: Small Flash Single
Post by: vtsteam on March 14, 2023, 01:58:43 PM
Thanks very kindly, Per. :cheers: :cheers:

We're in the middle of a Noreaster blizzard with 14" snow so far, so I'm out fighting to keep our road clear with the tractor. Running on generator. Predicted to continue for another day  :wallbang: No steam engine work for awhile....
Title: Re: Small Flash Single
Post by: vtsteam on March 17, 2023, 09:51:47 PM
30 inches of snow came down and took out power on Monday. Tuesday phone and internet were gone. I plowed for three days to get 600 feet through the woods to the road. Third day I was plowing with old outboard boat motor gas mix from last summer in the John Deere tractor because I'd completely run out of regular gas. Luckily had about 15 gallons of diesel for the Listeroid generator. That's still running now,. uses about 2/3 pint/hour. Looks like Canadian utility trucks have joined in here to help with the massive number of downed lines throughout the county. I heard there are 48 crews out working in this area. Phone and Internet came back an hour ago, so I can write this. Even this morning I saw trees leaning over the road on Rt.5 suspended by power lines -- three of them within a quarter mile. Cars driving under them. My wife driving earlier saw a black pickup truck suspended like a seesaw on top of a guard rail over a ravine.

So, uhh, no more work on the little steam engine to report yet...... :lolb:
Title: Re: Small Flash Single
Post by: Kim on March 17, 2023, 11:29:11 PM
Steve, quite the winter weather you're having over there!
I hope you guys can stay warm and safe!

Kim
Title: Re: Small Flash Single
Post by: vtsteam on March 18, 2023, 01:54:12 AM
Thanks Kim. Power finally was restored 8PM tonight. So much more light in here!  And hot water, too. :cheers: :cheers:
Title: Re: Small Flash Single
Post by: RReid on March 18, 2023, 08:16:54 PM
Man, Steve, you really got hammered this year. Hope that was the last of the big ones!
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