Moriya Stirling Engine Build

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Harold_V
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Re: Moriya Stirling Engine Build

Post by Harold_V » Thu Apr 01, 2021 3:53 pm

rmac wrote:
Thu Apr 01, 2021 3:46 pm
Harold_V wrote:
Thu Apr 01, 2021 3:37 pm
Generally the result of the tool making contact where it shouldn't.
That could well be what was happening. Working on miniature stuff with a pair of old eyes can be iffy sometimes.

-- Russell Mac
Yep! I'm no longer what I used to be, which I attribute, primarily, to my failing vision. I've noticed that when I don a second pair of glasses (reading glasses on top of my bifocals) I can see so much better.

I had a tendency to work with my nose close to the work when I was actively machining. I fully believe that my slight edge was due to the ability to see what was going on at the cut. It's ultra critical, and aided by an understanding of how a tool cuts, and how to make corrections when it doesn't cut as expected.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

Technical Ted
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Re: Moriya Stirling Engine Build

Post by Technical Ted » Thu Apr 01, 2021 5:46 pm

I have a pair of these as well as a pair of Optovisors. They both work great for small stuff like this. They fit over top of glasses just fine and I can wear them for extended periods of time with comfort. The Optovisor is a little better quality, but they are both fine.

https://www.amazon.com/gp/product/B0160 ... UTF8&psc=1

Ted

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rmac
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Re: Moriya Stirling Engine Build

Post by rmac » Sun Apr 04, 2021 5:54 pm

Two new questions:

I have the parts for the crankshaft all made now, but haven't put them together yet. Any reason not to use Loctite for that instead of silver solder? It would save a lot of tedious cleanup work, for sure.

The next step then will be to make a couple of connecting rods. It seems odd that the plans call for aluminum for the parts that form bearings with the crankshaft (marked in red on the drawing). Wouldn't brass or bronze make a better bearing material?

-- Russell Mac

connecting_rods.jpg

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NP317
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Re: Moriya Stirling Engine Build

Post by NP317 » Sun Apr 04, 2021 6:29 pm

My engine has both connecting rods made from 6061-T6 aluminum. The Power Conn Rod top is press fit (or glued) to a drill rod shaft.
They have shown no wear in the years of use I have subjected the engine to!
I did drill a tiny oil hole and cup on the top cap of the displacer conn rod, and oil it before every use.
The power conn rod top can easily be made from bronze, not being "captured" in the crankshaft assembly.
Their longevity has surprised me.

I imagine you could easily glue and pin the crankshaft. We silver-brazed them for my classes, as an instructional opportunity.
Yes, lots of cleanup to do after. Also part of the lessons.
RussN

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rmac
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Re: Moriya Stirling Engine Build

Post by rmac » Mon Apr 05, 2021 10:08 am

Thanks, Russ.

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rmac
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Re: Moriya Stirling Engine Build

Post by rmac » Tue Apr 13, 2021 3:34 pm

Progress Report #12:

Crankshafts, power cranks, and piston yokes all done.
NP317 wrote:
Sun Apr 04, 2021 6:29 pm
I imagine you could easily glue and pin the crankshaft.
I went ahead and assembled the crankshafts with Loctite 609, then cross-drilled through the round parts for some little pins held in place by more Loctite. The pins don't show up very well in the picture, but they're there.

I didn't mean to, but somehow I managed to glue a pair of bearings onto one of the crankshafts. I put them on the shaft a day after assembling the crankshafts. All I can figure is that there must have still been some uncured Loctite on the shaft that I didn't notice. In any case, the bearings are NOT coming off now! Fortunately, they're in the correct position.

When cutting out the middle section of the main shaft, I found by experiment that it's easier to set up a slitting saw for an accurate cut than it is to file away the mess left when doing it by hand with a hacksaw.

-- Russell Mac

crankshaft_parts_and_piston_yokes.jpg

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NP317
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Re: Moriya Stirling Engine Build

Post by NP317 » Tue Apr 13, 2021 4:16 pm

Nice looking crankshafts + parts. You do quality work.
If I ever made another crankshaft for these engines, I would use your technique.
Funny that your bearings got glued in place too! No harm no foul.
None of us here have EVER done that. Right?

I just tore into my old Moriya engine today. The knocking sound was increasing and I figured it was time to evaluate it for worn parts and fix it.
Surprisingly it is back together and fixed now!
The work quality from my students (mechanical engineers) was not up to my standard. but they did punch mark the stacked parts so I could reassemble them.
The main stud holes were not precise in position...

The only part I replaced was the displacer piston rod. Its diameter was worn 0.001 - 0.002" in the brass seal/sleeve and had lateral movement in the hole! The brass sleeve was still true i.d. That surprised me.
Oh, I also replaced the wrist pin at the top of the displacer piston rod. The old one did not survive removal.
The split con-rod bearing at the crankshaft was a touch loose, so I sanded the top cap down a touch until it was close again.

When reassembled I attached an electric drill motor to the engine shaft and ran in the engine for several minutes until it was turning smoothly.
Moriya is now mounted back on my wood heater in the Shop, waiting for the next fire.

Check off another task.
RussN

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rmac
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Re: Moriya Stirling Engine Build

Post by rmac » Tue Apr 13, 2021 5:23 pm

NP317 wrote:
Tue Apr 13, 2021 4:16 pm
Nice looking crankshafts + parts. You do quality work.
Thanks. You can hide a multitude of sins with a little bit of emery paper and careful photography!
The work quality from my students (mechanical engineers) was not up to my standard. but they did punch mark the stacked parts so I could reassemble them. The main stud holes were not precise in position...
Darned engineers! I'm an EE by training but wound up doing mostly software for a living. All this metal work is just for fun.

I've been lucky on the stud holes. So far I've been able to assemble any combination of parts from both engines in any random orientation without any trouble. However I did match up the displacer piston rods with their respective glands after I got them all sliding nicely. Probably have to do that with the power pistons and cylinders, too.
The only part I replaced was the displacer piston rod. Its diameter was worn 0.001 - 0.002" in the brass seal/sleeve and had lateral movement in the hole! The brass sleeve was still true i.d. That surprised me.
Hmm. It does seem like the brass part would wear first.
The split con-rod bearing at the crankshaft was a touch loose, so I sanded the top cap down a touch until it was close again.
I think I mentioned earlier that I plan to make those bearings out of brass instead of aluminum. Somehow aluminum just seems wrong.

-- Russell Mac

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NP317
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Re: Moriya Stirling Engine Build

Post by NP317 » Tue Apr 13, 2021 8:42 pm

"I think I mentioned earlier that I plan to make those bearings out of brass instead of aluminum. Somehow aluminum just seems wrong."

Wrong maybe, but 5 years of extensive use has proven the efficacy of the aluminum!
RussN

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rmac
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Re: Moriya Stirling Engine Build

Post by rmac » Wed Apr 14, 2021 8:08 am

NP317 wrote:
Tue Apr 13, 2021 8:42 pm
Wrong maybe, but 5 years of extensive use has proven the efficacy of the aluminum!
Fair enough. In case it isn't obvious by now, I'm guessing at a lot of this. Aside from "aluminum works", is there any other reason not to try the brass? Just for the bearing, that is--I want to make the rest of the displacer conn rod from aluminum to keep the weight down.

-- Russell Mac

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NP317
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Re: Moriya Stirling Engine Build

Post by NP317 » Wed Apr 14, 2021 9:26 am

I suspect weight was a deciding factor in choosing aluminum for the entire rod.
My engine is stock per design, except that the students used it ti research static balancing by adding machined weights to the ends the cranks.
Results are not highly evident, due to the small size of the engine and its lower operating rpm moving air.
But ti looks intriguing!
RussN

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rmac
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Re: Moriya Stirling Engine Build

Post by rmac » Sat Apr 17, 2021 9:40 pm

Progress Report #13:

Displacer connecting rods done. I deviated from the plans a little bit on these:

1. Made the bearings out of brass instead of aluminum, as advertised earlier.
2. Put a little oil hole in the top of the bearings, per RussN's suggestion.
3. Made the fork and the rod as two separate pieces, just because it seemed easier.

These are stuck together with Loctite 609. I didn't bother with the cross pins this time.

Now I'm starting to wonder how to keep the little 1/16" OD wrist pins from working their way loose. Press fit them into one side of the forks? More Loctite (carefully applied!)? Blobs of epoxy on each end?

-- Russell Mac

displacer_conn_rods.jpg

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