Author Topic: Doppelmotor - Double Acting Stirling Engine  (Read 3745 times)

Offline yogi

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #30 on: April 24, 2020, 03:34:32 AM »
I second Dave with monsterjaws.com (also selling on eBay). I couldn’t buy the aluminum for what I can get the jaws from them, and they are reversible.


Yogi

toolznthings

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #31 on: April 24, 2020, 01:56:09 PM »


The best out there. Lathe chuck soft jaws, too.   :ThumbsUp:

Offline yogi

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #32 on: April 25, 2020, 11:21:58 PM »
Up next the cylinder heads.

The two cylinder heads are identical, with the exception one has a bore for the piston rod.

The first side is turned and parted off.






Chucking really gently on the register, the second side is cleaned up.






Drilling the mounting holes and milling an air passage.






Finished cylinder heads.




Thank you for following along, and stay tuned for more.
Yogi

Offline yogi

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #33 on: April 28, 2020, 10:24:14 PM »
The next parts are the connecting rod, and the links for the displacer and power piston rods.

The process for making these parts is the same as before. Milling the profile, setting up soft jaws, finishing the second side...


















Thank you for following along, and stay tuned for more.
Yogi

Offline yogi

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #34 on: April 30, 2020, 12:41:37 AM »
Work continues... Today we have the crank disc.
Made from 416 stainless (thanks Brian). First side is turned.




Parting off.




Gently chucking on the outside diameter to clean up the second side. Before machining, checking the run out with a dial indicator, as it would be very easy to chuck the piece crocked.




Drilling and tapping for a set screw.




...and drilling and reaming for the crank pin.




The finished crank disc.




Thank you for following along, and stay tuned for more.
Yogi

Online Dave Otto

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #35 on: April 30, 2020, 01:12:12 AM »
Beautiful work Yogi!
I'm enjoying your progress.

Dave

Offline yogi

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #36 on: May 03, 2020, 11:54:27 PM »
Thank you for the compliment Dave!  :cheers:

Next, the gland nuts. The first operation is to face, bore and cut the thread. The nut has a 15 degree chamfer on the hex, as it is commonly seen on nuts. I machined that chamfer on both sides in this first set up.




Over on the mill, using a collet block to mill the hex.




Back on the lathe, I could pick up in the groove I cut earlier to finish parting off.




Cleaning up the face after parting off.




...and the finished gland nuts.




Thank you for following along, and stay tuned for more.
Yogi

Offline yogi

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #37 on: May 04, 2020, 09:43:04 PM »
Both the power piston and the displacer pistons have packing glands in the design. Both are quite similar, but not identical with few dimensions being different.

I was able to turn pretty much the entire part in a singe operation. Doing it this way I could guarantee the concentricity of the bore to the outside diameter and also the thread, and with that to the nut.

Here the glands before parting off.






This is how the parts came off the machine.






The only turning on the second operation was to clean up the burr left from the parting operation and breaking the edge.




Drilling the mounting holes.




The finished glands:




Unfortunately I have to go back to work and this project will have take a break. My original plan to have the engine finished by now didn't quite work out, but I still feel like I made a lot of progress and the goal of a pleasant distraction definitely worked. The drive to finish it, even if it was a lofty goal, did the trick with many quality hours spent in the shop.

Everyone stay safe and stay tuned for the continuation of this project.
Yogi

Offline Admiral_dk

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #38 on: May 04, 2020, 10:17:51 PM »
I think we all enjoyed your build so far - so we will be back when you get time to continue  :cheers:

Per

Online Dave Otto

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #39 on: May 05, 2020, 12:45:26 AM »
The glands look great Yogi, nice work as usual!

Glad that you get to go back to work, please stay safe. When they sent everyone to work from home at my job, I figured that I might also get some extra shop time too. Not much I can do from home except to check email and attend Zoom and MS Teams meetings, because I work in a shop. Well that didn't happen, they got approval for me and my two coworkers to continue to come into work.
It certainly has been different working in a ghost town; actually kind of nice in someways.

Dave

Offline Plani

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #40 on: May 06, 2020, 04:25:42 PM »
Really nice parts you made there! They're looking fabulous!

In the mean time stay safe and healthy, looking forward to see more updates.

Plani

Offline yogi

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #41 on: June 01, 2020, 01:53:54 AM »
Thank you gents for the kind comments. It's very much appreciated.  :cheers:

I can report some more progress on the engine whit the completion of the flywheel.
Corrosion resistance is always a consideration when I choose material for an engine. Steel would be the go to material, but I would want to address the possible corrosion. I decided to go a different route instead, with a two part flywheel, with an aluminum center hub and a bronze rim to get the required mass.

The shape of the aluminum stock, which was left over from another job (cut free from a bigger piece), wouldn't allow me to chuck it in the lathe. To be able to chuck it, I milled 3 flats at 120 degrees to hold it in the 3 jaw chuck.










Roughing some more material away to get to a good staring point.




Turning the first side.




Next, I machined the first side of the bronze rim. I machined a small shoulder which will locate the center hub in the rim.




Installing a set of soft jaws to finish the second side.




Still in the soft jaws, the rim is finished turned.




Milling the spokes.




The finished assembled flywheel. The center is a shrink fit in the rim.




Thank you for following along, and stay tuned for more.
Yogi


Offline Roger B

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #42 on: June 01, 2020, 08:18:33 AM »
That's an impressive looking flywheel  8)  :wine1:
Best regards

Roger

Offline Zephyrin

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #43 on: June 01, 2020, 08:26:57 AM »
beautiful finish on all these parts, immaculate...wow
 

Offline yogi

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Re: Doppelmotor - Double Acting Stirling Engine
« Reply #44 on: June 22, 2020, 08:12:02 PM »
Thank you gents for the kind comments!  :cheers:

The next part is what I call the swing.
First operation is to mill the contour to full depth.




The part turned over in the vise, the remaining stock is milled away and finished to final thickness.




Milling the fork ends using a slitting saw:




The last operation is to mill a pocket for the eccenter.




The finished part.




Thank you for following along, and stay tuned for more.
Yogi