Model Engine Maker
Engines => From Plans => Topic started by: EricB on March 02, 2021, 09:08:51 PM
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At long last I've started on my second steam engine. I have another PMR casting kit sitting on the bench but I decided to try one from scratch instead. I didn't think this engine would be too complex. I'm down for materials and I managed to break my lathe drilling out the cylinder, but here's what I have so far.
I was using a 3/8" drill for the final pass in the cylinder before finishing with a boring bar. The drill caught in the brass and quickly welded the MT0 chuck adapter into my tail stock ram. :'(
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If the ram is through-drilled, just heat the end of the ram with the stuck arbour in it close to red heat, and bash the arbour out with a hammer and a suitable sized punch. Hold the ram in a sturdy vise with soft jaws in it for the bash fest.
Is the ram from a Sherline or is it a Chinese import? If Sherline or Taig or other make of lathe made in USA you may be able to get a replacement ram. With Chinese ones you might be able to get a new ram from the importer but it may or may not fit. Seems parts interchangeability is not a given with the China machines, although purchase price is low.
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Commiserations on the mishap. Part of the territory, but a real pain when these things happen.
Some nice parts you have made already though...
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If the ram is through-drilled, just heat the end of the ram with the stuck arbour in it close to red heat, and bash the arbour out with a hammer and a suitable sized punch. Hold the ram in a sturdy vise with soft jaws in it for the bash fest.
Is the ram from a Sherline or is it a Chinese import? If Sherline or Taig or other make of lathe made in USA you may be able to get a replacement ram. With Chinese ones you might be able to get a new ram from the importer but it may or may not fit. Seems parts interchangeability is not a given with the China machines, although purchase price is low.
I did manage to get the adapter out of the ram using the leadscrew but both the parts are ruined.
My tools are Sherline. I should have the replacement parts in a few business days. The ram is ground to fit the tailstock so I had to give them the OD for them to match it.
I just thought that if they sell a 3/8" chuck it should handle a 3/8" drill right? Well maybe not. That was the first time I tried it and probably the last.
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Chris Rueby (code name crueby in this forum) is an expert with his Sherline tools and he could probably comment whether 3/8" drilling in brass is advisable / possible or not in your Sherline lathe.
Any twist drill as it comes from the factory will tend to snatch in brass. You can grind flats on the cutting lips of the drill parallel to the drill's axis for drills you plan to use only on brass, which will reduce the snatching tendency. However such drills will no longer cut steels well, if at all.
A better way in your machine may be to drill a smaller hole to start with and progressively bore it out in small steps to whatever diameter you need in any material. Much less risky for your machine and a lot less drama. The holes will be rounder as well. :ThumbsUp:
Glad to hear your replacement parts are on the way. Good luck with the engine! :cheers:
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Commiserations on the mishap. Part of the territory, but a real pain when these things happen.
Some nice parts you have made already though...
Eventually I autograph all my tools!
I like the way the cylinder looks. The pivot shaft runs through perpendicular to the bore and is soldered in before turning. I'm not sure the solder filled the entire joint. The cutting tools made knocking sounds when boring through that area.
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Chris Rueby (code name crueby in this forum) is an expert with his Sherline tools and he could probably comment whether 3/8" drilling in brass is advisable / possible or not in your Sherline lathe.
Any twist drill as it comes from the factory will tend to snatch in brass. You can grind flats on the cutting lips of the drill parallel to the drill's axis for drills you plan to use only on brass, which will reduce the snatching tendency. However such drills will no longer cut steels well, if at all.
A better way in your machine may be to drill a smaller hole to start with and progressively bore it out in small steps to whatever diameter you need in any material. Much less risky for your machine and a lot less drama. The holes will be rounder as well. :ThumbsUp:
Glad to hear your replacement parts are on the way. Good luck with the engine! :cheers:
Yup, I've had problems with drills much over 1/4" overpowering the taper adapter on my Sherline too, brass or steel. The MT0 is pretty small for that much torque. Never had it gall the parts together though. For the larger drills, I usually either start at 1/4" and step through the larger sizes, or drill 1/4 and use a boring bar to take the hole out the rest of the way. The boring bar usually gives better results, the larger drills tend to wobble slightly and give odd shape holes.
Chris
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Chris Rueby (code name crueby in this forum) is an expert with his Sherline tools and he could probably comment whether 3/8" drilling in brass is advisable / possible or not in your Sherline lathe.
Any twist drill as it comes from the factory will tend to snatch in brass. You can grind flats on the cutting lips of the drill parallel to the drill's axis for drills you plan to use only on brass, which will reduce the snatching tendency. However such drills will no longer cut steels well, if at all.
A better way in your machine may be to drill a smaller hole to start with and progressively bore it out in small steps to whatever diameter you need in any material. Much less risky for your machine and a lot less drama. The holes will be rounder as well. :ThumbsUp:
Glad to hear your replacement parts are on the way. Good luck with the engine! :cheers:
I've thought about modifying a set of drills for brass. I just haven't got there yet. Perhaps now's the time.
I was going up in steps but my index skips from 5/16 to 3/8. I didn't even think about the depth at the time but that's a .062" cut. No wonder it pulled loose.
Well I'm still learning.
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Yup, I've had problems with drills much over 1/4" overpowering the taper adapter on my Sherline too, brass or steel. The MT0 is pretty small for that much torque. Never had it gall the parts together though. For the larger drills, I usually either start at 1/4" and step through the larger sizes, or drill 1/4 and use a boring bar to take the hole out the rest of the way. The boring bar usually gives better results, the larger drills tend to wobble slightly and give odd shape holes.
Chris
Galling only took a second. The drill caught, spun the chuck, and locked up before I could find the off switch.
I made a boring bar holder for my first engine build. No excuses for not using it.
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Just a thought - don't throw away the damaged ram if the internal thread at back end is still serviceable. If the thread is OK, you could use the damaged ram to mount other attachments like a drill pad, tap holder, die holder, multi tool turret etc in future. The M0 taper could be bored out straight to accept close fitting straight pins / spigots on the accessories mentioned above.
Your boring bar mount looks great! well done.
The great thing about engine / model making machining work is that you learn something on virtually every job whether you have been doing it 5 days or 40 years. :cheers:
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Spent quite a few hours today making little parts and fixing mistakes.
Started with the piston and rod. Everything went smooth until I tried to slide the piston through the cylinder bore. No-Go. Now I know why reamers were invented. I had left the cylinder a few thou under so I resized and squared it up with a boring head on the mill. I still need to make a new piston.
Then I made the outboard head. It started as a chunk of 1/8" x 1" bar stock. The OD needed to be 1" so I had to make it round without reducing the width. For that I super glued it to a bit of aluminum in the 4 jaw. As it got close to size I shifted the part toward the side that had the largest flat spot until the opposing flats were equally removed. Once it was to size I finshed the outer end and moved it to the mill to make the bolt holes. A little heat from a kitchen torch to break the glue then back to the lathe to finish the inside surface.
I also started a few of the steam passages in the cylinder that I could do with the tools I have on hand. I need to go shopping.
Eric
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The replacement parts for my lathe arrived late last week along with some tiny end mills so I've made a little progress. I made the inside head parts and soldered them together, soldered the end onto the piston rod, and made a new piston.
Today was the two steam passages that connect to the cylinder bore and all the mounting holes for the heads and valve plate. Doesn't seem like much but it sure took all day.
I'll finish the exhaust port in the cylinder when I drill the steam holes in the valve plate.
Eric
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Hi Eric, that’s a very interesting engine. Coming along nicely.
MJM460
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I have a length of 12L14 on hand so today I made the end of the crankshaft. It's amazing how much work can go into a part that's so small.
I started on the lathe with the slug offset in the 4 jaw enough to drill and turn down the boss for the big end. I then moved to the rotary table on the mill and removed the material on the straight sides and the circumference of the big end. While I had it there I drilled the hole for the connecting rod drive pin. Then back to the lathe to part off and clean up the mess that made. Finally I clamped it back on the rotary table and finished the circumference of the small end.
Sorry I didn't take pictures of the process but here are the results.
Eric
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Very nice work.
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Nice looking parts Eric..... :Love:
:cheers:
Don
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Thanks guys. I want it to look good just in case it turns out to be a paper weight ;).
A pile of bar stock came today so now I can get on with the base and frame.
Eric
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The plans call for the frame to be a bent strap of aluminum. All the examples I've seen (so far) use straight pieces instead so I went for the bend. I probably didn't give it enough heat so it kinked. Aside from that I was able to get the about rest right. I'll give it another try.
Eric
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Hello Eric, good job. It's a good little engine that I made , https://www.youtube.com/watch?v=fi806GdXt7I
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Very nice! That's what I'm aiming for.
My second attempt at bending aluminum came out worse than the first so I think I'll mill the frame instead.
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Were you bending around a rod, or just freehanding it? Around a rod can work much better, start it with the bar clamped to the rod in a vise or with a small clamp. That will get you the first half or so of the bend - may have to move the clamp around to finish it off.
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I was bending around a 1" steel bar clamped in a vise. The stock I have is 6061 T6 so it's very hard, and I'm heating it with propane. Other than that I don't know what I'm doing. Everyone on youtube has a different story.
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After much meditation, here is my current plan for carving out the frame.
https://www.modelenginemaker.com/index.php?action=dlattach;topic=10234.0;attach=124919;image
The idea is bore the inside of the curve to size and then shape the outer curve on the setup shown below. I'm thinking I should be able to finish the rest of the shape holding in the vise. It's going to make a lot of chips.
I'm considering making a single strap to hold the part on the rotary table. What would you do?
Eric
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A couple other ways come to mind to grip the part for milling the outside - am sure that there are a number of others.
- If you have the adapter to fit your 3-jaw chuck to the rotary table (very handy item, I use mine a lot), you could reverse the jaws in the chuck and have them grip the inside walls of the bored hole. Even better would be the 4-jaw chuck, since it has a slot that can be used to clamp the chuck to the table using one of Sherline's little hold-down clamps (L-shaped with a bolt type). Milling on the outside of the piece puts force on the chuck which wants to un-screw the adapter, which would be very bad.
- Make a little arbor set like this:
(https://i.postimg.cc/m29D4SJh/Image6.jpg)
The bottom plate bolts to the rotary table using the t-slots in the table. For best centering, could put a little round piece on the bottom of the bottom plate that is sized to match the hole in the rotary table. I made a tooling plate for my rotary table for things like this. The top cap is pulled down by the center screw, and an optional little pin near the rim keeps anything from turning by the force of the end mill. The two steps on the bottom plate are to give vertical room for the hold-down bolts, and the smaller step is sized to fit the bore in the block.
With the block held in place:
(https://i.postimg.cc/0yqNyw1n/Image8.jpg)
Sure there are other ways too - thats half the fun of machining!
:cheers: Chris
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Hi Chris,
I like the idea of the arbor. Anything I use would need to be clear of the cutting tool so that rules out the chucks for me. I tend to autograph my tools.
For my progress today I cut down the stock to near final size and bored the hole for the inside of the curve. Lots of handwheel turning. I need a nap.
Eric
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Machined the outer radius of the frame today.
First I made a long strap clamp to hold the part to my rotary table. I figured if two tiny clamps can hold my mill vise down then this strap should hold the part with no problems.
I just needed to figure out how to center it up. I was thinking about what to use to make an arbor like Chris suggested but decided to look and see if I already had anything that would work. I have an end mill holder that will thread onto the chuck adapter for the rotary table and gives a concentric bore to align the table with the mill and an outer surface to align the part with the table. To make up the size difference between the end mill holder and the part I used painter's tape.
Eric
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Good solution!
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:ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:
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Very ingenious. Looks like it worked out very well.
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Thanks everyone for the comments. I'm starting to put too much emotion into this part, but I need to keep on it.
I had left the block oversized so I could be less concerned about placement of the inside bore, and I could center on that for the next steps. In doing so it left a step on each side after cutting the outer radius of the curve that I needed to remove.
I think I will finish all the other features on this part before I cut the center out.
Eric
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Those parts came out great! It can be stressful to get a good symmetrical radius on a part like that, but your method seemed to work out quite well.
Kim
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Those look really nice. Machining time is often 99% thinking and set-up and 1% cutting. :ThumbsUp:
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Excellent recovery Eric.
-Bob
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Still working. I set the frame aside for now to make some of the bits that mount to it, starting with the bearings. Since I hate cutting stock by hand I set up a tiny cutoff saw on my lathe for the brass. Sherline's cross slide does not like to be clamped like this and is easy to distort and bind so tighten gently.
I realised I would need some sort of stop for my mill vise. After searching the web for answers I drilled and tapped both sides of the vise 10-32 and mounted a strap clamp. I changed that out for one with a threaded hole for a moveable stop and started on the bearings themselves. The mounting holes are drilled from the bottom almost to the top. When I get around to shaping the top the holes will be exposed.
Today I sized a block for the bearing bracket that supports the flywheel and stacked up all the parts to get a peek of what the finished engine will look like.
I have a brass round for the flywheel that I started for another project and cut undersize.
Eric
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That looks like it's coming along really nicely, Eric. :ThumbsUp:
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Almost done with the bearings. Shaped the tops today. The first cuts brought the ends down to finish size and exposed the mounting holes on all 4 blocks. Next most of the excess was removed from the tops.
To make the top curves I first setup the rotary table and indicated it in. Then I made a mandrel and mounted a block on the mill. I was wanting to make sure I had enough clearance between the headstock and the rotary table so I made it a little long, but I failed to consider the X travel limits of the mill. My setup needed another 1/4" to get to the end of the part. I shifted the mandrel in the chuck to get the clearance, but I probably could have just removed the stop screw from the mill table.
I did the first bearing in steps to find the depth I wanted and then cut the other three to full depth without changing the Z setting.
The finish of the curves did not come out as nice as others I've seen. I rubbed them with a scotch brite pad to make tham look a little better. I guess I'll need to use some sand paper on them.
One of the bearings needs a pair of studs to mount the steam inlet which I need to make first.
Eric
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You are doing some nice work there Eric. If I may suggest, make yourself up a set of filing buttons to assist you in cleaning up the tops of your bearing blocks, They are invaluable and will help keep the surfaces flat and the edges crisp.
BC1
Jim
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Top notch work - really good work on making the top radii - a very difficult feature.
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Another commonly used method to round over the tops of the caps is to clamp them in the mill vise, with a small piece of round rod or a drill bit under the cap as a spacer - take a pass with the mill, unclamp/rotate the cap slightly, press down on the cap onto the rod while clamping again, take another pass. Only needs 6 or 8 passes to round it off, gives good results, still can need a little filing or sanding to smooth over the little steps that are left, but its an easy setup.
(https://i.postimg.cc/2Sznphns/IMG-4643.jpg)
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That is a really neat trick. :ThumbsUp: :ThumbsUp: :ThumbsUp: :ThumbsUp: :ThumbsUp:
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Thanks for all the comments. I'm having a good time solving the puzzles of how to make each part.
Jim, I was hoping to avoid making filing buttons but that's probably the best way to clean up the finishes.
Chris, I thought about using the method you've shown, but I paid a lot for that rotary table so I'm using it for everything!
I started working on the steam connection last night. For the inside head Elmer suggests using two pieces soldered together to "avoid making chips out of valuable metal." This part is basically the same as the inside head but cut from a solid piece. Lots of chips!
Eric
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Here is the rest of the steam connection work. It still needs a little more finishing, and the flange is a bit oversize. I need to get better about measuring.
Eric
Edit: I put it back in the chuck and worked the flange down to its proper size.
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I paid a lot for that rotary table so I'm using it for everything!
I get that! :ThumbsUp: :ThumbsUp: :Lol:
Top shelf work you are doing - really nice parts. Very impressed.
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I made the flywheel today. The brass round I had planned on using was much too large to turn into chips so I did some extreme parting from a smaller diameter chunk of stock using the mill. I know this is way past what I should have tried with such a little machine but it handled the load ok. The cut end looked horrible but so does a hacksaw cut.
I faced the sides and reduced the diameter also on the mill.
Not shown, I drilled and reamed the crank shaft bore and hogged out the sides using and end mill and the rotary table.
Finally I put it on the lathe, using the same mandrel I made for the outer radius on the bearings, and finished it to the size I wanted. I'm not sure if I'll cut some spokes, drill some holes, or leave it solid. I'll need to find a set screw to fix it to the crankshaft.
Eric
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That flywheel look great, a nice finish on it. Good on you finding ways to make small tools do big jobs!
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As a fellow Sherline lathe/mill user, I applaud your ingenuity on setups - always interesting to come up with new ways to combine the parts on the machine to do bigger parts. I notice you have the taller version of the toolpost, you need to add one of the headstock riser blocks to your wish list to let you turn larger diameters on the lathe. Clever how you worked around that on the mill!
:popcorn: :popcorn: :popcorn:
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Ditto on the cleverness (cleverity?) of your setups on the mill. I am envious of the finishes you achieve. Good work.
--Tim
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Thanks for the comments. I like to try and figure out how to do the work with the tools I have. Sometimes it gets strange. I need to make a couple of clock parts from large brass rounds and I've been thinking about them for some time. I decided to try out my ideas on this flywheel. A few things came up in the process.
The extreme parting photo shows the final position of the parting blade. I started in close and played out the length as needed to finish the cut. I figured I would end up using a hand saw but the machine handled it. I caught the spinning cutoff on a chunk of cardboard. I would not try this with other metals than free machining brass.
The facing cuts on the mill in the second picture are at the limit of the machine's rigidity. I was using a broad tipped tool and making fairly aggressive cuts. When it started chattering it almost vibrated off the table. When I try this again I'll reduce the mass on the mill table or shift it toward the center, and make lighter cuts with a smaller tool.
Chris, I have the riser set for the lathe. I used the mill because I've found that when you rotate the headstock the table Y travel stays perpendicular to the spindle axis (assuming you took the time to align the mill column in the first place). When you add the riser to the lathe that isn't true and you must indicate it in. I have my lathe aligned now and I'm not wanting to mess with it if I don't absolutely need to.
Eric
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Odd on the alignment, the key in the headstock should keep it parallel, unless the slot is out of line.
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Chris,
As Sherline likes to say their tools are precision milled, not precision ground. They have a tolerance limit for headstock alignment and when the spacer is installed those tolerances build up.
Eric
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Continued work on the frame today. Carving out the center went well, just took a long time on my small mill. Not much more to say but lots of chips. I still have six more holes to drill and tap. I managed to break a drill on the first hole. Lucky for me it was not deep and I was able to get the end of the bit out by enlarging the hole with an end mill. All my mistakes will be hidden by the cylinder.
Eric
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Frame looks great, thats a very different design than the usual one.
:popcorn:
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Very elegant frame Eric. A great start to an interesting engine.
MJM460
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Thanks for the comments. I have a lot of time and emotion tied up in this frame.
Today I drilled and tapped the final six holes in it. If I never tap another piece of aluminum it will be too soon, but I still have another aluminum part to make with four more tapped holes. I practiced on a scrap piece and still had trouble with the last hole. I also broke my fancy ratchet tap handle on the four bottom holes.
Eric
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Thats why I much prefer working with brass, more expensive but a pleasure to work.
Looking forward to seeing it progress. :popcorn:
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Are you using any lube when tapping aluminum? Brass can be tapped dry, but ali can grab without a little slick-um, especially if you don't break the chip often enough. Even a little candle wax rubbed on the tap helps, but usually I just add a drop of my way oil (10W hydraulic jack oil, with a small dollop of STP added). With that I find that even small taps down to 1-72 go just as easily as into brass.
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Yes I'm using a lube. What I have is a light machine oil and WD40. The chips aren't sticking to the tool so much as they jam when I back out to break the chips. I've had no trouble with larger taps, but the smaller ones in aluminum are making me nuts. I've read I should be using neatsfoot oil. Would that make a difference?
Eric
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Only thing I've found that works well in aluminum (and it does vary with the alloy, some are worse than others) is to back out the tap every turn or so, sometimes it means working the tap back/forth just in that small advance, since the chips jam so much. Especially with small taps like 2-56, they fill the flutes very quickly. Need to back it up every half turn to break the chips small, then back out completely every full turn or so.
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I guess I'll just have to keep practicing til I get comfortable with it.
Today I made some little bits and finished some others. First was link pivot for the valve gear. It mounts to the side of the frame below the the exhaust side bearing. I got to use the big strap clamp I made for the frame again. ;D
Next I finished drilling all the steam passages in the valve plate, and then drilled the exhaust ports through the valve plate into the cylinder exhaust passage. Someone once told me that Sherline's sensitive drilling attachment was worthless and I'd never use it, but I think it was quite handy for this task.
Finally I installed studs to attach the steam connection and made some nuts for them.
Next I think I'll work on the valve and the rest of its linkage. Then I can find out if it actually works or is just a paper weight.
The philips head screws are just for fitting the parts. Once I get around to final assembly I have hex bolts for them.
Eric
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You also don't want to use a tap wrench with too much leverage. For small taps I mostly hold this one by the knurled portion twixt thumb and forefinger. Much better "feel" that way, and my grip is not strong enough to break a tap from there (unless I bend it sideways). If I need to move up to the tommy bar for more leverage as the hole gets deeper, I get very careful and a little worried. And still use as little of the available leverage as possible. As Chris said, in aluminum especially back up early and often. Don't worry, you'll soon get the feel!
(https://i.postimg.cc/SNxMRBDY/IMG-0586b.jpg)
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I was using a pin vise for the small holes. Now I see I need to make Joe Pie's small tapping tools and one of those spring loaded guides, and also not try to go too fast.
Eric
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Eric....
Apologies if I have missed it, but will you not need a steam sealing n O-ring groove & O-ring on each side of each fixed bearing block?....
Derek
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Hi Derek,
This design has the seal in the steam connection in the area shown. Elmer's directions say use "graphited asbestos packing." I think I'll use something else. The exhaust side just stays open.
Eric
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Elmer's directions say use "graphited asbestos packing." I think I'll use something else.
I have used Glide brand dental floss as packing with success in my live steam locomotive. This is made from an expanded form of Teflon (ePTFE) and is somewhat similar to miniature Teflon tape.
My two previous Elmer's engines run on compressed air without any packing or piston rings, relying only on a thin film of oil for sealing.
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I guess I'll have to get some of that glide floss and give it a try. I use them pre-strung flossers.
Today I "finished" the sub-base, which consisted of finishing the top surface, squaring the sides, and drilling holes.
The problem I had to solve was how to hold it to finish the surface. I thought about making some low profile side clamps and fix it to the table but I didn't really like that idea. My solution was to CA glue it to another block held in the vise. After I surfaced the block with the fly cutter, I covered it with a layer of painters tape and rubbed that down. I then covered the bottom surface of my part with tape and rubbed it down the same way. After that I spread a layer of CA glue on the block in the vise, placed my part on top using a parallel to align the back edge with the front face of the mill column (Sherline). I've found using the front face of the column is a convienient way to align things with the table. Anyway, after the part was in place I put some weight on it and let the glue cure for a few minutes. It held incredibly well. I was able to flycut the top and mill the sides square without any problems. It came loose with a little pressure applied between the top of the vise and the bottom edge of the part.
To drill the holes I cut some spacers from 1/2" bar, taped over the top surface I had just finished and clamped it top down onto the mill table. Again I used a parallel against the mill column for alignment. After that it was spot drill, twist drill, and countersink for the six holes that hold the base and frame together. The three holes for mounting the engine to a plinth were drilled last.
I think I drilled the holes through the base a day or two after the tapping work on the frame but I didn't record any of that.
Still needed is the bearing bracket for the outboard end of the crankshaft to complete the base. That should be a straight forward task. It just needs to be the same height as the inboard bearing block.
One more puzzle I haven't worked out yet is the base should have a 5.5 degree angle on all the sides to simulate the draft of a cast part.
Eric
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Looking great!
Several ways to do that angle on the edges. One would be to clamp it to the table, like you just did, with a piece of thin stock along the edge of the table to tilt it, and run an end mill down the side of the part. A little trigonometry will tell the thickness of the shim to use. Lots of other ways, fun to work out which is best for what tools you have.
:popcorn: :popcorn: :popcorn:
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As Chris says, many ways to do the angle on the base. For those with a few dollars left in the tool budget (no idea who has that), and who are lazy in setups (like me) you can buy endmills with a taper angle ground on. The example at the link below is 5 degrees. Suppliers have many angles, but usually in increments of a full degree. With these tapered mills, you make a normal endmill cut and the surface is cut at the taper angle. Very handy for mould and pattern making. Hope this info helps. :cheers:
https://www.mcmaster.com/8936A37/
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As Chris says, many ways to do the angle on the base. For those with a few dollars left in the tool budget (no idea who has that), and who are lazy in setups (like me) you can buy endmills with a taper angle ground on. The example at the link below is 5 degrees. Suppliers have many angles, but usually in increments of a full degree. With these tapered mills, you make a normal endmill cut and the surface is cut at the taper angle. Very handy for mould and pattern making. Hope this info helps. :cheers:
https://www.mcmaster.com/8936A37/ (https://www.mcmaster.com/8936A37/)
Never seen those before - nice!
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Might be a good time to add a Tilting Angle Table to your tooling: https://www.sherline.com/product/3750-tilting-angle-table/ I use mine a lot.
Nice looking engine.
Jim
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Might be a good time to add a Tilting Angle Table to your tooling:
That's one of the handy Sherline accessories I just got. They were part of the Sale of the Month, last month. Sorry Eric. :ShakeHead:
The trig and shim method is potentially very precise, if done carefully. For the cosmetic job at hand you could get away with less careful but still with good results.
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Your use of CA and tape for work holding is clever. I've used CA for holding blanks in wood turning, but never in metal work. I'll keep that idea in mind! I have used carpet tape on a mill table for fly cutting and light grooving of plastic and graphite. Worked well for that, but cleaning off the goo was a pain, and I wouldn't trust it for heavier work.
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I've used this double-sided tape quite a bit to hold things together while working them - both metal and wood. And it works quite well. I've never had a problem with it. It holds tight, is very think and doesn't leave a sticky residue when you peel it off. Probably won't hold up to well at high temp, but as I said, I've done some milling work while holding with this sticky tape and haven't had a problem.
https://www.amazon.com/Spectape-ST501-Double-Adhesive-Length/dp/B003ASGL02/ref=sr_1_1?dchild=1&keywords=Spectape&qid=1621355148&sr=8-1 (https://www.amazon.com/Spectape-ST501-Double-Adhesive-Length/dp/B003ASGL02/ref=sr_1_1?dchild=1&keywords=Spectape&qid=1621355148&sr=8-1)
Kim
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I can't take credit for the glue setup. I found it here: https://www.youtube.com/watch?v=r6DCvtcU8_M
They do a lot more cleaning in the video to make sure the glue sticks, but as easily as it holds my oily fingers together I figured that was overkill.
Double sided tape would probably work just as good, but how would you know for sure it's making good contact with the parts?
I have the tilting angle table. I picked it up during one of their monthly specials back in early 2020. Set to a low angle it limits my Y travel so I can't get to the entire edge of the part. Set to a high angle the part gets in the way. It isn't designed to mount with angle parallel to the mill's X axis, which would solve the problem. I'd need to drill some more mounting holes in it. Still thinking about it.
Eric
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Eric, try turning the vise around on the tilt table, so the fixed jaw is back by the other end of the tilting plate, that gives more room to the sides of the vise. I don't remember if I had to drill more holes in the tilting plate to do that or not, was long ago and not very far away...!
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Hi Chris,
My experience with the tilt table is that the farther the work is from the angle center, the more the table flexes.
I think I'm going to try it with the spindle horizontal. With the fixed vise jaw close to the angle center both the tilt table and the part clear the column, the mill cutter can reach the part, and I can get the full Y travel. The short sides will be fun. I'll need to practice with this a bit first.
Eric
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Yup, I've had problems with drills much over 1/4" overpowering the taper adapter on my Sherline too, brass or steel. The MT0 is pretty small for that much torque.
Chris
[/quote]
About a year ago Sherline made available a tailstock with a #1 Morse taper to support their pen making customers. It's available in inch or metric and standard or zero adjustable handwheels. It increases the taper contact area by about 35%.
Rog
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Yup, I've had problems with drills much over 1/4" overpowering the taper adapter on my Sherline too, brass or steel. The MT0 is pretty small for that much torque.
Chris
About a year ago Sherline made available a tailstock with a #1 Morse taper to support their pen making customers. It's available in inch or metric and standard or zero adjustable handwheels. It increases the taper contact area by about 35%.
Rog
Sherline does say not to use it for high torque stuff, since the shell into the tailstock is so thin, but could be worth a try. Sometimes I do wish I could sprinkle some Rapidgro on the Sherline and bulk it up a notch! Still with some care and ingenuity it will make big parts.
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Yup, I've had problems with drills much over 1/4" overpowering the taper adapter on my Sherline too, brass or steel. The MT0 is pretty small for that much torque.
Chris
About a year ago Sherline made available a tailstock with a #1 Morse taper to support their pen making customers. It's available in inch or metric and standard or zero adjustable handwheels. It increases the taper contact area by about 35%.
Rog
Sherline does say not to use it for high torque stuff, since the shell into the tailstock is so thin, but could be worth a try. Sometimes I do wish I could sprinkle some Rapidgro on the Sherline and bulk it up a notch! Still with some care and ingenuity it will make big parts.
Sherline's instruction sheet states the largest diameter tool should not exceed .375". I went for the #1 Morse taper because I felt the #0 was too small for drills over 1/4" as you stated and not to enable me to use drills over 3/8" by using a larger chuck.
Rog
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Sherline's instruction sheet states the largest diameter tool should not exceed .375". I went for the #1 Morse taper because I felt the #0 was too small for drills over 1/4" as you stated and not to enable me to use drills over 3/8" by using a larger chuck.
Rog
Which instruction sheet is that?
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Sherline's instruction sheet states the largest diameter tool should not exceed .375". I went for the #1 Morse taper because I felt the #0 was too small for drills over 1/4" as you stated and not to enable me to use drills over 3/8" by using a larger chuck.
Rog
Which instruction sheet is that?
https://sherline.com/wp-content/uploads/2020/06/4112a_inst.pdf
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Sherline's instruction sheet states the largest diameter tool should not exceed .375". I went for the #1 Morse taper because I felt the #0 was too small for drills over 1/4" as you stated and not to enable me to use drills over 3/8" by using a larger chuck.
Rog
Which instruction sheet is that?
https://sherline.com/wp-content/uploads/2020/06/4112a_inst.pdf
Thanks Chris. I was looking for that kind of information in the normal lathe instructions.
Eric
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Practice makes perfect right? I made some test cuts on a bit of squared stock to see if my fixture choice would work.
Since I had just thrown the tools together to check clearances, I took it all apart to indicate everything in. I've used the tilting angle table before so I squared it up the way I had in the past, with the movable plate set at 90. Then I set it back to the 5.5 degrees I wanted and locked it down. I mounted the vise and indicated the fixed jaw square to the Y axis. I put the stock in the vise and made the first cuts. The picture shows how those cuts looked as they progressed. Not exactly what I expected. I finished the entire face and measured the stock which was no longer square.
More later, time for Jeopardy. :D
Eric
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Obviously my setup wasn't correct. The cutter was taking more material off the far end of the part than the near end so the angle table wasn't square to the mill table. Sherline's directions don't say how to get there from here. They suggest you visualize what a misalignment would look like. Well it looks like the picture above.
To solve the problem I took it all apart and checked everything with an indicator. Turns out the bottom mounting plate wasn't square to the mill table, the pivot axis for the angle plate wasn't square to the mill table, and of course the top surface of the moveable angle plate wasn't square. Only the last one matters. What you're trying for is alignment of the imaginary line where the plane of the spindle movement along the Y axis (or in my case a plane perpendicular to the spindle axis) intersects with the plane which is the top surface of the moveable angle plate. That imaginary line needs to be parallel to the movement of mill table.
To get it right I had to start with adding shims between the mill table and the bottom of the tilt angle table until I could use the play in the other mounting bolts for final alignment.
The results are shown in the picture below. I recut the first side to square up the block, flipped it over and cut the second side. This time the edge of the cuts came out parallel with the sides of the block. After the second cut the block was still square so I did the short sides too. All the side angles came out equal.
I'm almost ready to try this on the real part. I'll probably mark out some features on my test piece and make all the cuts again just to make sure nothing moves.
Eric
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Glad you got it figured out. I'm usually not smart enough to buy test piece insurance.
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Great result, good detective work on the tilt table, something to work on for later! :popcorn:
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Great result, good detective work on the tilt table, something to work on for later! :popcorn:
The tilt table is a very misleading device. It will do what they say but not how thay say it. Their website description says "With the base mounted square to the mill table, parts mounted to the tilted table can be machined or drilled at precise angles." That just isn't true. The moving plate has to be set square.
Eric
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I made another test piece today. This time I used a block larger than the part I'm making to see if my setup could handle it. Let's just say it isn't as rigid as I'd like it. With the cutter feeding conventionally, chatter and vibration got out of control very fast. It was enough to unlock the Z axis and crash the cutter into the part while walking the machine across my work table. Not Fun. The solution was only increase the depth of cut only when feeding in climb. My part isn't as thick as my test piece so hopefully I won't run into the same problem.
The other problem with this setup is the operator is very exposed to the rotating tool.
Eric
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I've had the same problem with chatter with my Sherline Mill using end mills. I've had better luck using a fly cutter. In this case, the mill would have to be configured in the vertical position.
I'm also wondering if the piece could of been mounted directly to the Tilting Angle Table. Again using the mill in the vertical position.
Jim
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I've had the same problem with chatter with my Sherline Mill using end mills. I've had better luck using a fly cutter. In this case, the mill would have to be configured in the vertical position.
I'm also wondering if the piece could of been mounted directly to the Tilting Angle Table. Again using the mill in the vertical position.
Jim
Hi Jim,
The only way I could control the chatter in this setup was to make lighter cuts as more of the side of the tool was cutting. It really only started when the width of the cut was greater than the diameter of the cutter. I guess the cutter was flexing more after that.
The problem with using the mill in the vertical position was the size of the part. There was not enough space between the spindle and the front of the mill column to fit the length of the cut. If you could mount the tilt table so that the pivot of the angle plate was parallel with the X axis of the mill then you could use the mill with the spindle vertical. That would take some extra mounting holes in the base plate of the tilt table but it could be done. A better idea might be an additional base plate that you could swap out if you needed to use the tool that way. I might add that to my to do list for later.
I finish the base using my setup as I intended today. No problems with chatter this time. I'm running out of parts to make.
Eric
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Spurred on by the good results making the draft on the base, I finished most of the work on the bearing bracket. I still need to shape the sides. I had zero problems tapping the holes in it. Probably because I spent so little time on it.
I'm running out of excuses for not finishing the slide valve and all its associated parts. Maybe tomorrow.
Eric
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Looking really, really good. That slide valve is calling your name!
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Getting closer to finished. Today I finished the bearing bracket, drilled and tapped the flywheel hub and installed the set screw, drilled oil passages in the tops of the bearings (though not called out in the bearing diagram they are shown in the overall diagram so I put them in), remade the thrust spacer for the crankshaft, and made a small pulley so the engine can do some work when its finished.
Still meditating on the slide valve.
Eric
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Lookin' like an engine now. :ThumbsUp:
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Is it just me, or does difficulty increase as the size of the part decreases?
This was a week of do I make a new part or can I salvage the mess I've just made.
I started with the rocker bracket. Looks simple enough. I figured I'd mill out the basic shape, drill some holes, and radius the ends. Easy! I don't even need to lay this one out, just clamp a bar of brass in the vise and start cutting. So I milled out the center carefully reading the hand wheels, then freed the part from the bar with a slitting saw. Perfect! Until I checked it against the diagram. Somehow it came out 1/4" too wide! Same as the diameter of the end mill I was using. OOPS!
Made a new one after carefully laying it out on the stock. Much better, but how do I hold it to drill the holes for the rocker shaft and keep them in line with the bracket? Maybe I should have done that first? Anyway I set it aside to think about while I made other mistakes.
My solution was to clamp my mill vise on its side and drill through that way. The two mounting holes were next, and I finished by milling the radii using the method Chris suggested on page 3 for the top radii of the bearings.
That's one.
Eric
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The next part on the list was the valve itself. I had a cutoff piece from the rocker bracket that was the right size and had a machined surface to use for the port face so I clamped it in the vise and went to work. I was on the last pass cleaning up the end of the cutout and turned the hand wheel in the wrong direction to start the pass.
I figured the part was ruined but I went ahead and finished it anyway, missing the width of the slot for the valve rod by almost +.020". Maybe I can salvage this one.
Next was the valve rod. I had made one earlier when I was trying to decide how to taper the sides of the base, but I didn't use any support while turning it and it came out a mess. I also did not have a die to thread it with at the time. I made the new rod supported by the follower rest and finished it to final size with fine sand paper. Once the die arrived I cut the threads and drilled and milled the flats on the driving end. I used Sherline's dividing attachment for this. It's easier to setup than the rotary table. I had to improvise a machinist jack. I should make a proper one some day.
I made the valve nut to compensate for the mistakes I made with the valve. The gouge in the face shouldn't hinder operation but the slop arround the valve rod might. To solve that I made a boss on each side of the nut to take up the extra space. The nut was turned from 3/8" stock and shaped on the mill with the indexing head.
Hopefully all this will work.
Eric
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"Experience" is just a shorter and more elegant way of saying "past mistakes". I think your valve fix is a good one and will work just fine. And I would argue that setting the vise on its side to drill the bracket is perfectly "right" way to do that job.
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I was once told it was best to learn from other people's mistakes.
Here are some pictures of today's progress. I only have one more part to make and a bunch of finish work like dressing up the heads on all those little bolts.
Along with the rocker shaft crank I also made the pins for the small end of the crank, the valve rod, and the link pivot (mounted on the frame), and pressed them all in.
I need to start thinking about my next project. I have a PMR #3 in waiting. My wife suggested cleaning the garage.
Eric
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This looks great.
Am seriously thinking of giving this engine a go next (or at least a version of it), and if I do this thread of yours will be an excellent resource.
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Thanks Gary!
In my original post I said I didn't think this design would be too complex. Well I missed the mark on that one. I was hoping to make something more interesting looking than a stack of blocks with a push rod sticking out. In that regard I think I succeeded. Here are the pictures of the engine with all the parts made and the final hardware in place. I'll let ya'll be the judges on if it's interesting looking.
There are a few parts I'm not pleased with. The fork that drives the valve rod is made according to the plans but somehow it looks out of place. I'll probably remake something with a bit more curve to it to replace it. The nuts for the steam connection are too large and the wrong material so I be making those again too. I'm also not convinced the solid flywheel is the right choice but I'm not ready to mess it up trying to cross out the center. I'll need to take it apart and clean up the finishes at some point too.
I don't plan on painting any of it but I will be mounting it to a wood base. Seems like the right thing to do.
To my surprize it actually runs with a little bit of air. What could be better than that?
Eric
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Good job Eric..........it looks great! :ThumbsUp: I'm betting that, if you let it age for a little while, you will end up being perfectly happy with how it looks now. :)
Jim
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Yes - a beauty!
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Hi Eric, an interesting engine beautifully done.
MJM460
P.S. Looking forward to the video!
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Well done Eric, congratulations! Those first runs feel great don't they? Watch out though, they tend to set the addiction hook. ;)
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Here's a video. Sorry but all you can hear is my compressor.
https://www.youtube.com/watch?v=r7IdMiCZDrY
Eric
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Runs great, looks great, nice and smooth. Excellent!
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Congratulations, Eric! That's a cute little runner! :ThumbsUp:
Kim
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Hi Eric, congratulations, it’s running really well. It is an entrancing motion.
Timing the valve would be interesting to get your head around.
MJM460
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Very nice!
Dave
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Thanks for all the comments! I had a good time building it and I learned a few lessons in the process. I'm already starting to think it looks fine the way it is, but I'm still going to clean some things up before I call is finished.
I think the valve timing is like most other steam engines. The valve is at full travel when the crank is 90 degrees from the piston rod. Just had to play around to find that point.
As for being and addiction, I think that ship has sailed! I was hooked the first time a made a part on a lathe.
Eric
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Great looking engine and a very nice runner too :praise2:
I really like the design and shape :cheers:
Best wishes
Per
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Eric, If I understand correctly that this is your first engine effort, then I am very much impressed. A beauty and a good runner! --Tim
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Well it took me almost 5 months but I finally made replacement nuts for the steam connection. Now I'm happy with how it looks.
Eric
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Much nicer proportions, improves it a lot!
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Yep........it's the little things that make the difference. Well done. :ThumbsUp:
Jim
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:ThumbsUp: :ThumbsUp: :ThumbsUp: :cheers:
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Cute little engine runs a treat. Congrats Eric on a great build… :ThumbsUp:
:cheers:
Don