Author Topic: Lehmann Stirling Engine  (Read 4571 times)

Offline toolznthings

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Re: Lehmann Stirling Engine
« Reply #30 on: March 08, 2019, 02:06:41 AM »
Lots of great progress !! Moving along nicely.  :ThumbsUp:
Thanks for the visit !
Brian

Offline scc

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Re: Lehmann Stirling Engine
« Reply #31 on: March 08, 2019, 04:23:52 PM »
Excellent :popcorn:

Offline yogi

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Re: Lehmann Stirling Engine
« Reply #32 on: April 05, 2019, 08:29:08 PM »
Thanks everyone for the kind comments! It's very much appreciated.  :cheers:

Progress is slow, but I do have a part to share with you guys.

The base plate is milled from 3/8" 6061 plate. I divided the milling operation into two, milling two sides at the time.
Carefully placing the plate on 123 blocks, making sure the blocks don't interfere with the tool path. Clamped down, again carefully checking the clamps are not interfering, the right and the left side are milled.




Finish pass:




I moved the claps one at the time to the side of the plate, making sure not to move the part from its position, to mill the remaining two sides. Again, making sure the clamps are clear from the tool path.






In the same set up, I spot drilled the location for the mounting holes. Here the base plate after it came off the mill:




The drilling and tapping was done manually on the Bridgeport.
The finished part:




And the mandatory family shot of the parts so far:




Thanks everyone for following along, and stay tuned for more.
Yogi


Offline yogi

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Re: Lehmann Stirling Engine
« Reply #33 on: April 20, 2019, 01:12:27 AM »

For the split bearings, I first milled the bronze stock into halves.






Chucking the two pieces in the 4 jaw, the bearings are turned and parted off.








Last operation is to drill holes in the bearing half's. In the bottom half the hole is for a pin to prevent the bearing from rotating, in the top it's for the oil passage.




The finished bearings:




And the bearing installed in the bearing blocks.





Thanks everyone for following along, and stay tuned for more.
Yogi






Offline yogi

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Re: Lehmann Stirling Engine
« Reply #34 on: May 10, 2019, 10:13:07 PM »
The next parts for the engine I made are the crank and return crank. They are made from 303 stainless.

The first side is finished to full depth.






The second side is then finished using the trusty soft jaws.






The finished cranks:









Thanks everyone for following along, and stay tuned for more.
Yogi

Offline Plani

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Re: Lehmann Stirling Engine
« Reply #35 on: May 11, 2019, 08:43:53 PM »
Great progress and very nice parts  :ThumbsUp: :ThumbsUp: :ThumbsUp:
Looking good!


Plani

Offline Art K

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Re: Lehmann Stirling Engine
« Reply #36 on: May 12, 2019, 02:27:17 AM »
Yogi,
Missed this build I will be following along. I have to admit that it is no fun boring a piece that long on the cylinder 8 inches. that's where you find how good your equipment is. Looks great so far.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline b.lindsey

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Re: Lehmann Stirling Engine
« Reply #37 on: May 12, 2019, 02:35:57 PM »
Wonderful family shot yogi. This really is quite a large engine but the motion is fascinating!!  Still following along.

Bill

Offline toolznthings

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Re: Lehmann Stirling Engine
« Reply #38 on: May 13, 2019, 01:13:55 AM »
As always, nice looking parts !   Following along  :popcorn:  :ThumbsUp:
Thanks for the visit !
Brian

Offline PJPickard

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Re: Lehmann Stirling Engine
« Reply #39 on: May 13, 2019, 11:06:55 AM »
Great work on a fav of mine! I love your Maho!

Offline Dave Otto

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Re: Lehmann Stirling Engine
« Reply #40 on: May 13, 2019, 11:45:56 PM »
Very nice Yogi!

Dave

Offline yogi

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Re: Lehmann Stirling Engine
« Reply #41 on: June 18, 2019, 12:29:44 AM »
Thank you guys for the kind comments and checking in on the project.

The engine has a set of levers for the typical Lehmann motion. My first thought was to bend some flat stock to shape. After an attempt at bending, which didn't turn out well at all, I felt that I have two choices. Either I'll build bending jigs or I'll machine the levers out of the solid. Machining out of the solid might seem a bit overkill, but building a jig is also a lot of work, and still no guarantee that I'll achieve the accuracy I'm looking for. Milling out of the solid will be a challenge and a lot of fun, so out of the solid it is.  ;)

The first operation was to drill the holes and mill the radii at each end of the lever. Making sure I have enough stock left to clamp it in the vise for the next operation.








The pieces laid flat in the vise, the contour is milled out.








Using a set of accurate machined spacers, the levers are finished. In this operation the tapper in the lever was added on both sides.








The two finished levers:





Thanks for following along, and stay tuned for more.
Yogi


Offline toolznthings

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Re: Lehmann Stirling Engine
« Reply #42 on: June 18, 2019, 01:35:34 PM »
Levers came out great  :ThumbsUp: Machining was the best way. Hate trying to bend thick parts to size.
Thanks for the visit !
Brian

Offline b.lindsey

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Re: Lehmann Stirling Engine
« Reply #43 on: June 18, 2019, 02:33:55 PM »
Very nice looking parts yogi!!

Bill

Offline Ye-Ole Steam Dude

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Re: Lehmann Stirling Engine
« Reply #44 on: June 18, 2019, 08:45:51 PM »
Hello Yogi,

Beautiful job on the levers.

Have a great day,
Thomas