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




 

[Dreeves]

Looking good. Keep the pics coming.

Dave

[Don1966]

Looking great Phil and I like the way you cut the slot in the guide very intuit......

 
Don

[philjoe5]

I worked on the crankshaft bearing and here’s a short pictorial of what I did.  I didn’t have a piece of  bronze or brass in a size suitable to make this bearing but I have lots of Durabar cast iron and so decided to make this bearing with it.  This is a 2x scale model, BTW, and I suppose I should have stated that in the title.

I sawed, and milled a block to the overall dimensions and made it a bit thicker in the flange than the plans called for. 

Next, I drilled and reamed the crankshaft hole ½”.  Without removing the work from the vise I drilled the 4 mounting holes.  I realized that these clearance holes for a #8 screw would need to go 1.3” or more deep.  Hopefully, they will not wander.

Now I’m ready to turn the ends on the lathe using the four jaw chuck, but first I removed most of the stock on the mill to lessen the amount of interrupted turning required.

Now I’m ready for some lathe work.  This almost looks like a casting!

Here’s the setup on the lathe.  I used a ½” dowel in the bore to indicate from and a live center to improve rigidity.  Yes, that's a brazed carbide turning tool doing an interrupted cut in cast iron.  And no, I don't seem to have any problems with this cutting tool.  But I'm not turning at high rpm's.

I turned the side entering the column first to a diameter of 0.875”.  Here I’ve verified that this end will fit through the column.  Note that it stands proud of the column on the cylinder side by 1/16” according to the plans.

With both ends turned I did a test fit which was good.

Finally, with the fit confirmed I drilled the oil hole to finish the part.


Thanks for looking in

Cheers,
Phil

[crueby]

Nice work on the bearing, looking good!   

[b.lindsey]

More nice progress Phil. Great pictures as always too!!

Bill

[Thor]

 Nice work Phil, what you have done so far on the engine is looking good.

Thor

[philjoe5]

I worked on the pivot bearing and its associated nut.  I turned the pivot bearing in two steps past the flange although the plans described a straight run past the flange.  The reason being at this 2 x scale, the end of the bearing would be a ¾’ thread and a corresponding tap for the nut.  I didn’t have these, didn’t want to buy them, didn’t want to thread single point on the Logan, so I just made the thread for the nut 5/8” – 18 NF using a tap and die that I had.

After turning the diameters, I cut the 5/8” – 18 threads using an adjustable wrench to hold the hex die, and I manually rotated the chuck while maintaining pressure from the tailstock on the die.

Then I reamed the hole 3/8” for the pivot pin.

I cut off the work from the stock and faced the flange end to a thickness of 0.120”, this end is fitted into the 0.125” deep recess on the column.

I made the bearing retaining nut from some 1 1/8” brass stock.  Drilled and bored it out to about 7/8” to accommodate a spring.  I'm using the dial indicator to warn me when I'm close to the bottom of the blind hole.

Then I drilled a pilot hole and bored it to 0.578” to accommodate a 5/8” – 18 tap.  I tapped this on the Logan lathe by hand turning the chuck while following the thread with the tailstock.

Tthe bearing is shown installed in the column with a brass ring spacer that represents where the actual valve will go.  The valve has spacers on either side of it to act as bearings for the valve.

These are the parts for the bearing

The valve is the next part to be machined.  Thanks for looking in and thanks for the kind words Thor, Crueby, Don, Bill, Dave

Cheers,
Phil

[b.lindsey]

Its beginning to look like an engine Phil. All the parts are looking good as well. Still following along here ...may even have a go at this one at some point.

Bill

[Gas_mantle]

Looks good Phil.

It's gonna be a monster size version when it's done. 

[philjoe5]

Thanks Bill

Gas_mantle:  A friend of mine showed up at one of model shows with this double acting Oscillating cylinder engine.  It was in very good condition and ran well on air.  The wide pulley on it suggests it was actually used to drive some piece of equipment.  It has a generous oiler as well.



My friend didn't want to sell it and I thought it was a neat engine so I've been searching for plans for a double acting wobbler for over a year.  Marv put me onto Elmer's #36 so I decided to build it in my friend's scale which is about 2x Elmer's.  Now, of course, I can reverse mine when it's finished

Cheers,
Phil

[Tennessee Whiskey]

Phil, the build is coming along nicely.  Now,  when you finish the 2x,  you should do a 1/4 scale to present beside it   

Cletus

[philjoe5]

Cletus,
The smallest screw in the original plan is a 2-56, diameter of 0.086", so 1/4 scale is a screw with diameter = 0.021".  That's a screw that's off my tapping chart, outside of my eyesight range, a bit too fragile for my aging jitters   However, I appreciate your confidence in my ability to tackle the insane    Plus, if I built it 1/4x scale, my loving wife would probably think I tracked a sliver of scrap into the house and she'd chuck it in the trash.

Cheers,
Phil

[philjoe5]

This weeks project was making the valve.  Starting with some 2 ¼” steel alloy (1144) I turned a diameter to 2.000”.  Then I drilled to 5/8”, bored to about 0.73” and reamed it to 0.750”.  I cut off the work on the bandsaw.




Then I placed the valve in the 3 jaw using this technique that ensures it won’t end up lopsided in the jaws. 

Faced the valve to a thickness of 0.375”.

Next operation required the rotary table and after making a fixture to hold the work in the MT2 collet of the rotab, slotting commenced.

After a few mishaps (read “broken”) using an extra long 3/16” end mill to clear the hex bolt head, I switched to a double ended end mill held in an ER-32 collet and finished the job.


I’m stopping work on the valve at this point because I want to design some kind of reversing lever.

Now, it occurs to me that I can test the valve operation by injecting some compressed air into the column and rotating the valve by hand.  The black ink mark on the valve shows the location of one of the slots. 

Well all seems to be in order with air coming out of the face from the proper ports so I guess I drilled and plugged the right ones in the column.

Thanks for checking in.  I’m motivated to finish this engine for the Cabin Fever Expo – I’ll get one balloon for my Opposed Piston Steam Engine (Elmer’s #30), and I’m going for a second one for this build.

Cheers,
Phil

[Don1966]

Looking good Phil and still with you......


Don
 

[Tennessee Whiskey]

Boy don't you just hate it when your tool breaks over when you try and stick it out too far  . I really like the "pin alignment ". Since I bought some pin gauges,  I've used that method to get several parts indicated in " close enuf " . You keep on,  I'm going for a  and  and I'll be back.

Cletus

[Dreeves]

It will look like a birthday party at our table. 😂 I have 6 elmers stan has a few you have a few Scott has one

Dave

[b.lindsey]

If I make it to CF, I can add six more to the total Dave.

Bill

[b.lindsey]

Oh...nice progress Phil 

Bill

[philjoe5]

Thanks for the comments guys.  It will be good to see everyone at the Cabin Fever show.

Work continues and seriously guys, your encouragement motivates me

Cheers,
Phil

[philjoe5]

I have been working on the cylinder.  This part threw me a slight curve in that it has a rectangular component and an arced segment.  So I wondered if I should start with a round or rectangular piece of stock.  It was a 50/50 proposition but I chose the wrong direction initially.

I happen to have some round stock in the 3” range and started with that.  I turned it to a diameter that the arced segments called for.  Unfortunately, that led to rectangular sides that did not meet at sharp corners
.


This prevents the crosshead guide from mating properly.  And I couldn’t mill the sides any further without cutting into the air passages.


I cut my losses and restarted with  rectangular stock.  This time I approached the job with the following strategy.  The face that mates with the column needs to be perpendicular with the bore.  So I milled the stock accordingly, then bored the cylinder and drilled and tapped the crosshead guide holes.




Unfortunately, boring on the mill/drill has never produced good results with my equipment.  The result was a bore with a 0.002” taper – unacceptable. 


So, I clamped the workpiece in the 4 jaw, and indicating off of the bore on the small end, I bored the cylinder out on the lathe to 1.263”.


At his point I came to the realization that the rectangular piece is best machined by:
Milling to correct overall dimensions
Boring the cylinder
Drilling/tapping the cylinder head and crosshead mounting holes
Drilling/tapping the cylinder mounting holes and air ports
Everything else is cosmetic.

Here’s a family shot with the cylinder attached and a temporary nut holding the pivot pin to secure the cylinder against the column face

At this stage I decided to check air flow in both valve positions and everything seems to be working OK, with air entering the cylinder ports as expected.


Thanks for looking in

Cheers,
Phil

[Thor]

 The cylinder looks great Phil, when I made my version I didn't bother with the arced segment, just milled the cylinder as a block.

Thor

[philjoe5]

Thor,
After the initial tragedy starting with round stock I was tempted to just make a block, but decided to put the arcs in there to dress it up a bit.

Cheers,
Phil

[philjoe5]

The flywheel assembly consists of a crankshaft, crank web and crankpin.  The crank web serves as a flywheel also.  I had some 3” brass and used a 1” thick slice for the flywheel


After facing both sides true I drilled and reamed a 7/16” hole with a ½” register.  Then I drilled/tapped 5/16” – 24 NF threads.


Turned a piece of ½” stainless to 7/16” diameter to fit the flywheel.  Secured it with  Loctite.  After curing I drilled a 3/16” keyway at the crankshaft junction, inserted a key, added Loctite and finally cleaned up the face.  I made a crankpin to fit.



I made the piston and crosshead using the same approach.  I cut the stock from oversized stock, faced them to length.  Both were drilled/tapped ¼” – 28 NF.  A piston rod was made from 5/16” stock, threaded on both ends.  The piston stock was attached and turned to fit the bore, which turned out to be 1.262”.  The crosshead was turned to fit the guide in the same manner, then milled flats on opposite sides were produced.  Finally, it was reamed to accept the crankpin.



The working end of the engine was assembled and the crankshaft was attached to a portable drill.  Movement is good, with no tight spots or clearance issues.

I just realized this post has me working at each of my three lathes.  How does anyone make do with less?

So far, so good.  I’ll tackle the cylinder heads next.

Cheers,
Phil

[crueby]

Drilling in the joint of the whhel and the shaft for the pin is interesting. Since it was between softer brass and harder steel was there any problem with the drill walking to the side?

[Flyboy Jim]

Following along Phil. Thanks for posting what didn't work out so good, along with what did! 



Jim

[Thor]

 You are making good progress Phil, the engine looks very nice. You are lucky to have three lathes, I only have two, and I would not part with my smaller lathe.

Thor

[philjoe5]

Crueby - I'm using screw machine drill bits.  They're shorter than Jobber length and I am not seeing a problem with them walking in this application.  I suppose if they did a bit I wouldn't notice here since its a blind hole for the key.

Jim, Thor - thanks for looking in.  I can see light at the end of the tunnel now

Cheers,
Phil

[philjoe5]

Working on the cylinder heads I squared up a piece 2” x 2” aluminum.  I drilled four clearance holes for attaching to the cylinder and drilled/tapped a 5/8” – 24 hole for the packing gland.



To minimize a lot of interrupted turning on the lathe I milled away most of the excess on the end with the spigot.



I made a blank packing gland by turning some brass true, cutting 5/8-24 NF threads and drilling with an “O” drill (0.316”) for the 5/16” piston rod.  I used an adjustable wrench to hold a hex die, and turned the chuck by hand while feeding the die onto the workpiece using pressure from the tailstock drill chuck.  Brute force, but it did the trick.



I set up the work in the 4 jaw by indicating on the blank packing gland that was screwed into the cylinder head.


Turned the spigot on the end.


Cut off the work on the bandsaw.  Then I faced the cylinder head to its specified thickness of ¼” and turned a register for the cylinder.


Installed the lower cylinder head (without packing gland) and checked for clearance issues.  None were noted.


That's the latest progress.

Cheers,
Phil

[b.lindsey]

 It's coming along well Phil. Nice project to be following along on and I enjoy your updates.

Bill

[Don1966]

Looking good Phill missed a few updates but caught up now.

Don

[Thor]

 The Cylinder head is looking good Phil, nice work. I guess you will soon have it running.

Thor

[philjoe5]

Thanks guys for the comments.  Couldn't help myself since all parts except the packing for the gland were on hand.  Here she is running in single action mode.  A lot of finish work to do yet

<a href="https://www.youtube.com/watch?v=0Wa9A4Gxh6Y" target="_blank">http://www.youtube.com/watch?v=0Wa9A4Gxh6Y</a>

Cheers,
Phil

[Thor]

 Congratulations Phil, you have a runner.

Thor

[Dreeves]

Phil, can't wait to see it at cabin fever. Your going to need 2 air lines to keep her full of air 
Dave

[b.lindsey]

Thanks for the video Phil. Seems to be ticking over very smoothly!!

Bill

[philjoe5]

Thanks Thor, Dave, Bill.  But I still need to work out why she won't reverse.  Runs pretty well in one direction, but so far no reverse.  I have to try reversing the air intake to see if that changes things.  Hey, Cabin Fever in 1 month, can't wait.

Cheers,
Phil

[philjoe5]

I was not excited with the engine running in single action mode.  It required at least 50 psi to keep it running even though the engine seemed to turn over easily with no tight spots.

I was a bit suspicious of that crank web/flywheel combination.  It was made from a 3” diameter x 1” thick piece of brass and at just over 2 pounds I thought it would be sufficient to do double duty. 

I found a nice piece of scrap cast iron 0.7” thick x 3.5” diameter so I decided to make a “second” flywheel with it and see if engine performance improved.  After facing both sides, I bored a central hole 0.750” diameter for fitting to a hub. 



I turned a hub to fit this hole, then I drilled/reamed the hub ½” to fit the crankshaft.  I drilled and tapped two 10-32 holes for set screws. 



I fastened the hub to the flywheel with some Loctite and after curing, I drilled a 1/8” hole at the interface of the hub and flywheel.  Then I put a 1/8” piece of brass with a drop of Loctite in the hole.  After curing I milled most of the excess brass off, then faced to flywheel to finish it.



Now, with this second flywheel adding almost 2 pounds the engine runs slowly on 20 psi.  It may be that doubling the scale requires a bit more mass in the flywheel.  Once I get it to run in double action mode, the flywheel may be unnecessary. 

Side view 1:



Back view :



Every engine seems to have its own peculiarities and this one is no exception.  I double checked my valve slot dimension and it follows the plan OK.  But the valve position has a very small arc in which the engine runs well in either direction.  That made setting the valve for the first running a bit time consuming.  I managed to get the reversing feature working but the valve position does not have a lot of “wiggle room”

There are two springs working in this engine.  One of them holds the cylinder against the column.  I think I have that one right because I’m not seeing many bubbles of oil coming out of that interface.  So it’s strong enough to form the seal, but not so strong as to be a major source of friction.  The other spring forces the valve against the column.  I think that one is too weak since the valve often drifts off its optimum setting causing the engine to slow down.  And note the oil spray in the back view around the valve.  I’ll need to work on this.

Finally, I need to address the double acting feature.  I may need to remake the packing gland since installing it introduces too much friction.

I should have this engine at Cabin Fever as a work-in-progress.

Cheers,
Phil

[philjoe5]

I'm reposting this video just to complete this thread.  Apparently, the original post was lost during this recent incident with the server.  No need to reply if you already did.

<a href="https://www.youtube.com/watch?v=q6W7oXXRmhM" target="_blank">http://www.youtube.com/watch?v=q6W7oXXRmhM</a>

Cheers,
Phil

[Thor]

 Phil,
 Thanks for reposting the video.

 Thor