Elmers Uniflow

[two dogs]

Hello,
I'm going to make Elmers #48 Uniflow engine and document it here. I've not seen anything on the web about anyone (other than Elmer) building this.
It is an interesting design as far as the mechanics, but is not what I consider one of his more attractive engines, too plain. I'm going to make some changes, mostly related to the stock on hand and the limitations of my equipment. I'll bling it up somewhat after I get it running.
I started with the busiest part; the cylinder.
Top pic:
Facing off the top to qualify. Using tall parallels to de-emphasize the condition of the stock. I'm only taking off enough to clean it up
Middle pic:
Locating qualified side against fixed jaw, using a piece of round stock at movable jaw to eliminate "rock"
do for two more sides
Bottom pic:
Holding in a V block will keep sawcut ends square
Started with a pc of 1" square, was able to fully clean and obtain .985" square

 

[two dogs]

Next I milled the entry slots and drilled the angled holes then drilled and reamed the cylinder bore. Size not too critical, will make piston to fit. More important to have smooth and not tapered. The rest is just drilling and tapping.
I decided to plug the exhaust holes instead of using the blockoff plate and then mill them even with the top surface. Can't even tell there were holes there.

 

[Metal Butcher]

I also have not seen an example of this motor. As a big fan of Elmer's designs I'll be watching you build with keen interest.

Interesting set up you have in the last picture. As a newbie I usually use a simple set- up by centering the work piece in the vise jaws on top of a pair of low parallels or a pair of precision ground square tool bits. I have a pair of V-blocks but have yet to use them.

I look forward to seeing your build progress.

-MB

 

[4156df]

Mark,
Looking forward to following along. Thanks for taking the time to post.
Dennis

 

[two dogs]

MB
This step was to cut the ends. Normally one would qualify the 4 sides, then clamp on 2 of them and side cut the saw cut ends with an endmill. You can't stand it up if the ends are saw cut, it will follow any irregularity of the end
Clamping in 2 V-blocks allows you to keep the sawcut ends square with the sides

 

[Metal Butcher]

MB
This step was to cut the ends. Normally one would qualify the 4 sides, then clamp on 2 of them and side cut the saw cut ends with an endmill. You can't stand it up if the ends are saw cut, it will follow any irregularity of the end
Clamping in 2 V-blocks allows you to keep the sawcut ends square with the sides

I will square one side/end of the stock by side milling (sounds like this is what you normally do). Then I band saw cut to length. The band sawed end is clamped face up on parallels and centered in the vise for squaring and facing down to length. I use this method because I was told by an experienced machinist to never clamp a work piece off center. This is why I never tried using V-blocks the way you did. I think it would be difficult for me to center and balance the three pieces on parallels in the vise, at a repeatable height, with no bottom support for the work piece, and face down to an accurate length. At least for me anyway. Hopefully you can understand what I'm trying to say with all this run-on mumbo-jumbo. On occasion and with no other option I will set up and check a workpiece using a precision square.
I guess there are many ways to archive the same goal.
-MB

 

[kvom]

That's actually an interesting technique, esp. if you square the sides before the ends.

 

[two dogs]

Kvom,
Thats what I had done, squared up 1" matl to .985" and the ends were saw cut. Face milling leaves a better surface finish.

Mark

 

[GailInNM]

Mark,
Great start.
You will like the Uniflow.
I built one about 20 years ago.
I just fished it out of the cabinet, lubed it, and it still ticks over nicely on 5 PSI. It has been at least 10 years since I ran it.
I probably ought to clean it up some as the brass is all tarnished and it looks like it is about 60 years old. Although the antique look is kind of nice.

Gail in NM,USA

 

[two dogs]

More parts:
Base and bearings. Simple drill, ream and tap parts.

Cylinder Plate and Crosshead Guide. I made them from aluminum cuz I don't have any brass that size and can't afford ant right now. I'll press fit them together. You can't see it, but I put a small spot on the crosshead guide at the very end at the top. This will help me line it up with the cylinder plate when I press them together.

Some turned parts, Heads, valve and packing nut. Heads still need to be drilled. See next post for packing nut

 

[two dogs]

The packing nut:
I don't like to make screws. For the packing nut I bought a 10-32 brass Phillips screw. Just faced it, turned it to about .250 then drilled thru (after first plunging with an endmill) then milled the side slots. The head matches the 10-32 of course. Don't think I'll have any problems with the coarser pitch(Elmer called out 3/16-40).

 

[two dogs]

More stuff!
trial fit of some of the parts I've made

 

[two dogs]

More parts:
1) Piston. I made it from Delrin. I will only be using air to power this so there should be no problems

2) Turning Eccentric:

3) Making the offset. I don't have any real experience with a 4-jaw chuck, even though I have one. I ended up using my boring head in my mill to turn the offset. Just reversed the boring bar and rotation.


4) The crankdisk. Faced and turned to clean then put in my cnc mill to mill the cutouts and drill the hole. I tapped it 2-56 and will make a bushing to fit the con-rod.

Edit: Before too many of you think I'm crazy to think that a single toe clamp offcenter will hold this to mill it, I should clarify it. I had pressed the crankshaft onto the crankdisk and drilled a hole into the fixture to hold the crankshaft. The clamp kept the assembly from rotating.

 

[two dogs]

Milling the flywheel clearance on my cnc mill.
What's cool is that the spindle was turning at about 7500 RPM and my 6 year old digital camera stopped motion!

Made the piston rod yesterday. Basically 3/32" brass rod with a 3-48 thread on each end. Twas an adventure! Finally got the tool centered dead nutz and settled on a suitable rpm and depth of cut. Going slower than I would have thought and a pass of less than .006" (dia) max worked. Next time a dienut!

 

[two dogs]

It's been too hot lately here to be out in the shop when I have the time, so haven't gotten much more done. Thought I'd check in though with a few thoughts so far.

So far things have gone pretty well. I'm going to leave the cylinder square for now till see how it looks assembeled. Same for the baseplate, I'll leave out the side cutouts. I used round stock for the clevis and crosshead and left them round. Just personal preference. I may decide to remake the crosshead and mill the flats after assembly. The crankscrew will be instead a bushing .186 od and .11 id to accept a 4-40 screw instead of the 5-40 called out in the plans.
Anyhow it's getting close, only a few parts left and I'm going to be able to do it all from my scrapbox.

The plans are OK as far as that goes, but I don't like the way Elmer does his dimensioning. All in fractions, my calculator has gotten a workout on this project. Another slight gripe is dimensioning some details from one edge, some from another edge and still others from another detail all on the same part. Sometimes his dimensioning is diffrent from one end of the part to the other. It's very different from what I'm used to (in the machining trade for 35 years) and can cause mistakes if you're not careful. ;D
Enough griping. Next one of his engines I make I'll take the time to model every part in Solidworks and dimension them how I like
Hopefully get it done in about a week or so

 

[Metal Butcher]

The plans are OK as far as that goes, but I don't like the way Elmer does his dimensioning. All in fractions, my calculator has gotten a workout on this project. Another slight gripe is dimensioning some details from one edge, some from another edge and still others from another detail all on the same part. Sometimes his dimensioning is diffrent from one end of the part to the other. It's very different from what I'm used to (in the machining trade for 35 years) and can cause mistakes if you're not careful. ;D
Enough griping. Next one of his engines I make I'll take the time to model every part in Solidworks and dimension them how I like
Hopefully get it done in about a week or so

Wow! I can sympathize with what your saying! I thought it was just me. I have the same exact gripes. I convert all the fractions using a small chart, and then do all the math on paper with pencil. I bought a simple electronic calculator for $1, but can't bring myself to use and trust it. If you were to see all the scrap paper with math all over my floor, bench. and machines during a build, you would say H... S...! And believe me I'm no math wizz! I do all my calculations three times and still make grotesque errors!

Mt best boo-boo to date was a 3/4" piston sticking out the top a of a cylinder by a 1/2"!!!

If you had a few problems, can you imagine me with only a few years of playing around, on my own and all alone, with no back ground, no previous experience, being taught by Professor Clueless M.B.!

Laughing at myself, its therapeutic!:big: :big: :big: :big: :big:

Thanks for posting, it gave me the oportunity to vent, and made me feel a little better about myself.

-MB

 

[two dogs]

Well, even though I have many years in the trade, what I do at work is quite different from what I've been doing at home, so I'm somewhat of a beginner in that regard. I've only been model engineering for two or three years. The equpiment I have worked on at work is much more rigid and accurate than what I have at home but as I do things I find out what my home equipment can do and more importantly CANNOT DO. I have to have two mindsets.

I had scrapped my first cylinder for this build by not paying attention. All the info was there, but I got in a hurry. Can't blame that one on Elmer, but after that I slowed way down.

Laughing at myself, its therapeutic!:big:

Hey, we gotta have a sense of humor. If I didn't laugh at myself a couple of times a day I just wouldn't enjoy life as much! ;D ;D ;D

 

[two dogs]

Been a while since I've posted. Family obligations and a recalcitrant computer.
Made the flywheel. Cut a pc of alum bar 2.75 square then drilled and reamed a .2505 hole in the center.
Then stuck it to the front of my 5C collet adapter with some double sided tape using the live center to locate it and add support.. The tape is to just keep it from rotating, it's some really sticky stuff I get from work. Wasn't sure how it work and I was in a daring mood, so to speak. I left it square and set my program to only take .01" per pass. Worked great! No problem with it rotating and I was able to do something else at the time (still nearby of course!) I then turned to a dia of 2.55 then drilled and tapped a side hole for the setscrew. I drilled slightly larger then the 8-32 tap I used .75 deep.
After that was done, I milled it down to .55 thk (all I had for stock was 1" thick) , then mounted it on to a pc of .250 drill rod in my 5C collet and turned to a dia of 2.5 then faced one side. Flipped around then faced to .500 thk.
After this I thought I'll try to bling it up some. I turned a .02 deep groove on each face using a 1/16 wide cutoff tool ground with a full radius. Again, wasn't too sure how my lathe would handle it so I was real conservative. Used a D.O.C of .006 and .002 as a finish to clean it up. I was pleased how it worked out. I'll probably paint the groove blue or black then lap the surfaces to clean

 

[two dogs]

Made the con-rod. I didn't document this very well. I started one then realized that my toolpost would hit the live center. So I started over.
I laid it out on a CAD system where the limits of the part were, where the flats should be and the holes. The only cricical dim is hole to hole. I then Dykemed the 3/8 brass rod (Elmer said to use flat stock) and transfered the measurements. Faced the end and drilled a center hole>
Off to the mill. Faced off 1/8 and 3/32 respectively and drilled and reamed the holes. Rotated 180 deg (checking the underside with an indicator to verify) and faced to 1/8 and 3/16 thick.
After this, I transfered back to the lathe to my 5C collet holder, brought up the live center and set the offsets. Made a G-code to turn a taper and let'r rip.

 

[Maryak]

Two Dogs,

It's coming together nicely. :bow:

Best Regards
Bob