Elmer's Double Acting Reversing Wobbler

[philjoe5]

Has anyone built Elmer's Double Acting Reversing Wobbler?  I have the plans from the John-Tom site but the photos are impossible to read.  A few closeups would be much appreciated.  Thanks

Cheers,
Phil

[Thor]

Hi Phil,

 I have built a simplified version of Elmer's #36, without the reversing gear. You will find my write up  here (bottom of the menu)

Thor

[Dreeves]

Phil, I think I built that one. I will post a picture tonight if its the one I can post what pictures you want

Dave

[philjoe5]

Thanks Thor, that's a really nice writeup you did about building it.  Thanks for sharing it.  I had the same thought about using the crosshead guide to close off the cylinder and eliminate the cylinder head on that side.  I'll make that decision down the road. 

Dave, a few photos of the engine, front and back would be appreciated.  I want to show my friends and family what I'm building and there isn't a clear photo of the finished model on the John-Tom site.  I must have more engines to build because so far I'm pretty sure I could rattle off the ones I've built thus far without missing one 

Cheers,
Phil

[Dreeves]

Phil, I just look at the engine up. I did not build this one. But not that I have seen it I need to 

here is a picture I found if its the same one

Dave
http://tomwade.me/tw/machinist/elmer/images/36_vert_revers_wobb_mb.jpg

[Thor]

Hi Phil,
 
 Thanks for your nice words. I have made several versions of Elmer's #36, all using the same stroke, but with different bores. Combining the cross-head guide to close off the cylinder has worked well for me. I have started fabricating the part from tubing and a metal plate that I silver solder together. I have an ER-32 chuck for my small lathe and just mount the cross-head guide in a collet to turn the spigot that fit the cylinder and drill a through hole same size as piston rod. If I want to make a gland I have to drill and tap from the other end of course.

Thor

[philjoe5]

Dave - that photo is perfect.  If you know the builder let me know as I'll want to credit her/him

Thor - I'm planning to build this engine at a 2x scale.  It may eventually be a display engine in our maker space.

I don't know when I'll start it, but likely in the next month or so.  I'll post my efforts here.
Cheers,
Phil

[mklotz]

Here are a couple of pictures of my version of this engine...

[philjoe5]

Dave,
I found the builder - it's Rick Marszalek whom I'll credit if I use the photo anywhere

Marv, thanks for the photos and for alerting me to the plans for this engine.  It should be a fun build. 

Cheers,
Phil

[philjoe5]

I've decided to build this engine and have started where I usually do



i'll post whenever I complete a part

Cheers,
Phil

[b.lindsey]

Glad to see you start on a new project Phil...I'll sure be following along.

Bill

[philjoe5]

A summary of this past week in the shop follows.

Starting with a solid block of aluminum, I milled it true to dimensions for a 2x scale engine.  I reamed a hole dead center on one end and made a dowel to fit the hole.  The dowel will be used to center the block in the 4 jaw chuck.
Next, I milled the cylindrical portion to remove most of the material before turning on the lathe. 

Then I turned the diameter to specifications.

Using a steady rest, I drilled, then bored the guide


At this stage I realized I hadn’t drilled the four clearance holes for mounting to the cylinder.  Happily, the OD was 1.125” and that fits the largest 5C collet, so I held the work in a collet block for this operation.

The last step involved milling the two opposed slots in the guide.  I could easily distort the guide by exerting sufficient clamping force in the vise to hold it.  So I used a bar with two threaded clamping studs and tightened this up snugly, the unmilled part of the guide resting firmly on the base of the vise.

And the final result

Thanks for looking in

Cheers,
Phil

[b.lindsey]

That turned out great Phil. Thanks for the update!!

Bill

[Thor]

 You are making good progress Phil, I assume you will keep us updated.

Thor

[philjoe5]

I worked on the column this past week.  It doesn’t require any tricky stuff, but there are lots of holes, some meeting other drilled holes, some blind.  It took some study on my part to figure out how all the passageways connected up.  My only disappointment in the plans is that the ports are not dimensioned.  They can only be drilled using the prescribed drilling jig.  I know that is common practice for some but I’m not a fan of them.  But I bit the bullet and used the one prescribed to do the job.  No other nasty stuff except a 1/16” x 1.15” deep oil hole that was put in at the end.  I really did not want to snap that drill bit off in the hole.  Patience and lots of chip clearing got the job done.

Here’s a picture story:
Starting with the face of a newly milled piece of aluminum 1.00” thick x 2.5” wide by 6.4” long.  The face that mates with the cylinder was fly cut.  Here I’m boring a countersink for the pivot pin bearing.  The other holes are bored or drilled for the crankshaft bearing and cosmetic appearance.


Next, 4 holes are drilled/tapped 8-32 for the crankshaft bearing.


The drilling jig was prepared and using temporary bushings in the pivot pin and crankshaft holes I drilled 4 ports holes using a #21 wire drill (0.159”).  This picture shows drilling the top passageways.  I had to use an ER-32 collet chuck to have adequate space in the z axis. 



With all holes drilled and tapped, here are front, and back views.



Now there are 6 passageways to plug.  They’ve been tapped 10-32 for just 5 full threads.  I made some aluminum plugs, 3 of which are shown here.  They were installed with a drop of blue loctitte and allowed to set up.

The plugs were trimmed off flush with a slotting saw.  Note that one of the air ports, also tapped 10-32 has a black circle around it.  That was a reminder to not put a plug with blue Loctite in it!


Finally a light polish with sandpaper and the plugged holes are nearly out of sight.  A bit more work and they’ll disappear.

The next part I’m working on is the crankshaft bearing.  I don’t have a piece of brass or bronze in the size required so I’m using a piece of cast iron.  A steel crankshaft in a cast iron sleeve should not pose any problems in this air powered engine.

Thanks for looking in.

Cheers,
Phil