Author Topic: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine  (Read 5798 times)

Online mikehinz

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Wellll, here's my start on my 2nd engine!  It's a Elmer's 36 Reversing Oscillator at 2x from the original scale and done in all imperial measure.  I selected this as I thought it represented a reasonable next step to further my machining technique.  Plus I wanted to really learn Fusion 360 and this gave me a good reason to do so.  The original drawings are not that clear in certain respects and I wanted to scale it up without making a bunch of mistakes while cutting metal.  So, over the last couple of months I've been slowly drawing the engine, making lots of mistakes, and redrawing numerous times, but I think I've gotten something close finally. 

To start this, you'll note some raw stock with an engine hidden in there somewhere!  Also, I've attached a few renderings and screenshots that i did in Fusion, just to prove that i actually drew it!  Finally, I've attached a single 2D drawing of one of the first components that I'll build, that being the base.  My thinking is that I'd upload 2d drawings as I go along so you can see what I'm attempting to make and then have some pix of the actual machining process of whatever part(s) I'm working on.  Does that sound reasonable and interesting enough?

Also, I do have one issue in the Fusion model.  I've managed to make a joint between the cylinder and the column and rotate it so as to prove the air passages all matched and the rotation angle was correct, but so far, I've NOT managed to animate the entire engine.  The failing is my current lack of understanding of joints and animation within Fusion.  I'll be working on that as I go.  I'm kind of certain that I've got everything correct so that the engine will run, but there could be some small dimensional error that would prevent that from happening.  I'd LOVE to run this engine virtually and hopefully I will soon!

Any suggestions or comments on this project are greatly appreciated!

Thanks.    Mike
« Last Edit: September 08, 2018, 04:42:47 AM by mikehinz »
MIke
Wichita, KS, USA

Offline zeeprogrammer

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #1 on: August 16, 2018, 03:02:13 AM »
I'll be interested in how you get along with Fusion 360 and animation.
An area I'm particularly interested in is animating cams.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Online mikehinz

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #2 on: August 16, 2018, 12:46:58 PM »
Carl, I'll certainly keep this thread updated with any successes or more likely failures, with Fusion 360.  I'd done various 2D CAD projects over the years and I must say that 3D is/was very hard for me to grasp, but now that i can do at least the basics, I fully understand why the industry has transited almost entirely to 3D.  I find that now I scrap very little as my mistakes are now much more 'virtual' than they used to be.

Later this afternoon, I hope to get some of the stock cut to basic size and to start taking to exact size on the mill.  Even more hopefully I hope to remember to take a few pix of the process!

Mike.
MIke
Wichita, KS, USA

Online b.lindsey

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #3 on: August 16, 2018, 12:57:18 PM »
Already off to a great start Mike and the drawings look good too!!  More importantly, you already understand the basic rule here...if there ain't a picture of it, it didn't happen  :lolb:

Bill

Offline toolznthings

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #4 on: August 16, 2018, 07:14:21 PM »
Looks great ! Keep the posts coming will be following along.
Thanks for the visit !
Brian

Online mikehinz

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #5 on: August 17, 2018, 01:48:10 AM »
Here are some pix of today's progress.  I cut all the material to rough size and squared up all the stock.  The base plate is to exact dimension and the other items are square, but not to final dimensions yet.   Nothing too complex yet but it took a fair bit of time.  I ran my saw about 3 hours to cut all the stock. 

The stock I get is mostly from The Yard here in Wichita.  It's a fantastic place and they have tons of drops from the aircraft industry.  If you get the drops they are only $1.50 per #, but there's guaranteed to be no straight side on any of the stock!   They do have some non-scrap AL stock but I tend not to go for that as it's currently $2.50 per #.  All their round stock is not considered scrap and goes for the higher price.  I also got the 3" round material there and it turns out to be 4140, but it was cheap so I'm using it for the flywheel. 

The pix show my roll-around tool cart that I put all my lathe and milling tooling plus I have a surface plate on top that i cover with the wood cover and use a work surface.  I like this method as everything is organized and handy and I can roll it to where I need it. 

Tomorrow my goal will be to get all these items to size and get the flywheel to the required thickness and get a center hole thru it.  I'll probably make an arbor to true the OD as has been suggested, but I need to get the thickness close first. 

You can probably get a little sense of my garage shop.  To quote mrpete222, "I don't know how anyone lives without a Bridgeport!". 

All for today. 

Enjoy!

Mike

MIke
Wichita, KS, USA

Online mikehinz

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #6 on: August 17, 2018, 01:51:55 AM »
A couple of pix of the aftermath of today's work.  It got bloody hot in the garage by late afternoon so I didn't clean up today.  i'll need to spend some time in the morning with the shop vac to get things cleaned up before i start in again. 

Mike
MIke
Wichita, KS, USA

Online b.lindsey

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #7 on: August 17, 2018, 01:56:09 AM »
More nice progress Mike. Maybe the shop gnomes will clean up for you overnight   ;)

Bill

Online mikehinz

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #8 on: August 17, 2018, 02:04:13 AM »
I have a couple of materials related questions that i thought I'd ask in a separate entry.  I'll need to order a few bit of stock here shortly so i want to decide what exactly to order or pick up. 

So far:

-  The base, column and cylinder are 6061 AL
-  The flywheel is 4140
-   All the various shafts will be W1 drillrod which I think I have on hand already.
-   For the cylinder pivot and crank bearing I was planning to use SAE 660 bronze bearing material.
-   For the cross head I was also planning to use SAE 660.
-   For the cross head guide I was planning  to use 1 1/8" DOM tubing and bore it to the required ID
-   For the piston, i had THOUGHT about Delrin, but in my LMS thread, there was a suggestion NOT to use Delrin.  So my question is, what's the alternative?  I could make the piston out of cast iron.  That's backwards from most engines, but shouldn't that work?  What about 12L14?  Or brass, or even SAE 660.  I'd like to keep the cost reasonable, so cast or 12L14 is a LOT cheaper than brass or SAE 660.
-   For the rotary reversing valve, I believe the original drawings show brass and it would certainly look and work well, but 2" OD brass is EXPENSIVE.   What about cast or 12L14 or Delrin for the valve?

Thanks very, very much in advance for considering my newby questions on material.  I have a fair bit of experience with various materials from my previous life, but it doesn't apply well to small mode engines, i fear.

Mike
MIke
Wichita, KS, USA

Online mikehinz

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #9 on: August 17, 2018, 02:07:27 AM »
More nice progress Mike. Maybe the shop gnomes will clean up for you overnight   ;)

Bill

That would be great, but I can tell you what the downside is.  If the gnomes don't do it and i don't do it, and some swarf gets tracked into the house and then if my wife steps on it,  it won't be a happy fun time around here! 

Hence my shop vac is my most used tool in my garage shop!

Mike.
MIke
Wichita, KS, USA

Offline zeeprogrammer

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #10 on: August 17, 2018, 02:11:21 AM »
A couple of pix of the aftermath of today's work.

 :lolb:

All swarf and no parts.

:lolb:

It's not too often I see a pic of the just the aftermath.

Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Online b.lindsey

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #11 on: August 17, 2018, 02:51:37 AM »
I would use brass or the 660. What diameter are you looking at at 2x scale? If you have CI on hand, I don't see why it wouldn't work though.

Bill

Online mikehinz

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #12 on: August 17, 2018, 03:13:16 AM »
Bill, I'm not sure which part you're referring to, but the piston in this engine will be 1.25"  OD by .50 length.  The reversing valve is 2" OD x .375 thickness.    I'll have to order some 660 for sure and could go ahead and order some brass. 

What's the best place to get small quantities at a good price?  Online Metals and Speedy metals both stock 660 and brass but it's just over $100/foot NOT including delivery.  I'll check Amazon and eBay that sort of material just seems expensive!

Thanks.

Mike
MIke
Wichita, KS, USA

Offline AOG

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #13 on: August 17, 2018, 04:08:51 AM »
Will you be running this engine on steam at any point? If not, with a piston that big, I would make it from 6061 aluminum. Make it .005 undersized and seal it with a silicone o-ring. That should keep the costs manageable. For the valve, I would make it out of 2.5 x .375 brass bar instead of round bar. Just turn it round on the lathe.

Tony

Offline gary.a.ayres

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Re: Elmer's 36 Reversing Wobbler - 2x - Imperial - Mike's 2nd engine
« Reply #14 on: August 17, 2018, 08:59:57 AM »
This is going to be an interesting thread!

Will follow...

gary