Manson Hot Air Engine Build

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Harold_V
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Re: Manson Hot Air Engine Build

Post by Harold_V »

I'm curious how you achieve the nice surface finishes your parts display.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
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rmac
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Re: Manson Hot Air Engine Build

Post by rmac »

RussN wrote: Nice save.
Thanks! I engage in similar mischief all the time when I'm working with wood. There, though, it's pretty easy to make repairs that are virtually invisible, and plain old yellow glue is generally stronger than the parts to be joined. Probably need to think about welding or brazing to get decent results in metal.
Harold wrote: I'm curious how you achieve the nice surface finishes your parts display.
I grind away my sins on a homebrew disk sander setup on my wood lathe.

-- Russell Mac

sander_table2.jpg
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Harold_V
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Re: Manson Hot Air Engine Build

Post by Harold_V »

Thanks. The cross-hatch you achieve lead me to my question.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
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rmac
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Re: Manson Hot Air Engine Build

Post by rmac »

Harold_V wrote: Fri Jul 30, 2021 4:25 pm Thanks. The cross-hatch you achieve lead me to my question.
Aha. The cross hatch pattern wasn't intentional. I musta just presented the part to the disk in a couple of different orientations. I guess to do a proper cross hatch pattern you'd first need to build yourself a miniature Blanchard grinder!

-- Russell Mac
pete
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Re: Manson Hot Air Engine Build

Post by pete »

Years ago there was a few articles in the Model Engineer Workshop magazine to basically turn almost any bench grinder into a miniature Blanchard grinder. Obviously it takes a wheel change to a cup type, but it orientated the grinder in a vertical position and it's then swung around a pivot point. They called it Swing Grinding. Much less information than the magazine detailed, but this gives the basic idea of a once available semi commercial kit of parts to do so. http://modelengineeringnorge.weebly.com ... inder.html
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rmac
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Re: Manson Hot Air Engine Build

Post by rmac »

pete wrote: Years ago there was a few articles in the Model Engineer Workshop
magazine to basically turn almost any bench grinder into a miniature Blanchard
grinder
How about that! And here I was just joking.

-- Russell Mac
pete
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Re: Manson Hot Air Engine Build

Post by pete »

The more I learn about machining the more I figure out that at some point whatever you can think up, somebody somewhere has already done or tried it. :-)
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rmac
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Re: Manson Hot Air Engine Build

Post by rmac »

Today's project was the hot end and its cap. They look about like the corresponding parts from the Moriya engine, except I had better luck with the silver solder this time. I put a generous chamfer in the big hole in the flange to give the solder a place to go, and that seemed to help.

-- Russell Mac

manson_hot_end.jpg
Last edited by rmac on Sun Aug 01, 2021 12:06 am, edited 2 times in total.
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rmac
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Re: Manson Hot Air Engine Build

Post by rmac »

pete wrote: Sat Jul 31, 2021 3:39 pm The more I learn about machining the more I figure out that at some point whatever you can think up, somebody somewhere has already done or tried it. :-)
Replace "machining" with "anything" and I tend to agree.

-- Russell Mac
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rmac
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Re: Manson Hot Air Engine Build

Post by rmac »

This is the piston for the Manson engine. I'm looking for ideas on how to hold it while I machine the two slits in the side and drill the four holes near the bottom and the one hole hear the top.

The orientation of the hole in the top relative to the slits is important. The orientation of the four holes near the bottom is less important, but it would be nice if the actual part matched the drawing.

I have a crude spin indexer. One idea is to screw the part into the end of a cylindrical scrap that I can then chuck in the indexer. But I'm worried about how to make sure the part doesn't come unscrewed from the scrap while machining. The piston is already honed for a nice fit in the cylinder, so I can't just grab it with a pair of pliers and torque down on it. Maybe this is a job for Loctite, with heat and/or solvent to get it unstuck after the machining is done? Or some other kind of temporary glue?

I could also abandon the indexer and just perch the part on a parallel in the milling vise. I actually like that idea better because the part would be supported better, but then I'm not sure how to accurately rotate it by 90 degrees.

Any better ideas?

-- Russell Mac

piston.png
Last edited by rmac on Wed Aug 04, 2021 8:51 am, edited 1 time in total.
pete
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Re: Manson Hot Air Engine Build

Post by pete »

I'd suggest using a piece of machined square plate, thread to match the bottom thread on the piston, maybe add a few more tapped holes for a hold down clamp pressing down on the piston top. Multiple tapped holes so you can move that hold down to various other points to gain access as each quadrant is machined. Make the fixture as accurate as you can and then it's accuracy will ensure the parts accuracy. Depending on what your doing it might take a bit of indicator work, vee blocks etc to also hold the piston horizontal for drilling. But an accurate square plate allows easy indexing. Like most things, the fixture will take longer to make than the machining your doing to the part.
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rmac
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Re: Manson Hot Air Engine Build

Post by rmac »

Thanks, pete.

The threaded square plate sounds like a really good solution. With such a thing screwed on the end of the piston, I can just set the piston on a parallel in the milling vise like I was thinking before, hang the square plate off the end of the vise, and then indicate on it to get the piston rotated correctly.

And since the plate won't be supporting the part in any way, I'm not worried any more about it coming unscrewed. So no glue or hold down clamps needed, I don't think. Okay, maybe a drop of super glue just to make sure. I know it releases easily with a little bit of heat.

Off to the shop now to try it. Thanks again!

-- Russell Mac
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