Author Topic: Myers Stirling Stove Fan  (Read 2074 times)

Offline Dave Otto

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Re: Myers Stirling Stove Fan
« Reply #30 on: October 25, 2019, 04:48:11 PM »
I think that put a small groove so the oil could flow around the bearing race; that was 15 years ago when I built it. :) The oil tends to collect in the outer race and gets spread around when the fan runs.
I only add a few drops once in a while, usually when running all day at a show.

Dave

Offline bent

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Re: Myers Stirling Stove Fan
« Reply #31 on: November 25, 2019, 06:40:41 PM »
A bit more done in our icy cold garage this weekend.  I bought a flycutter from McMaster to use to finish the upper housing displacer piston bore.  But they only sold 2-1/2" long bits of M2 tool steel for the cutter, and I needed to try and bore to 4.25" or so.  So, bought a longer chunk of A2 steel, and ground and hardened it.  Then re-ground it when I realized I hadn't provided enough relief...and then re-honed it at home several times because it got dull very quickly and the little mini mill would stall out.  Sorry, no photos of this process.  I do need to buy a decent bit of M2 for it though, the A2 just won't harden up as good as the high speed steels.

But the setup and freshly bored part was the same as needed to bore the relief cuts for the standoffs that hold the upper housing to the base.  The standoffs are 0.50" diameter, which puts the relief cuts at 9/16" diameter per print.  Hmm, no 9/16" cutters in my inventory so it looks like I need to use the boring head.  I dialed in on the centers of the bolt holes using a drill bit, switched to a 1/2" end mill in a collet to cut to a set depth (and marked the depth of the bit in the collet to hopefully get pretty close to the same depth on each of 4 cuts) (photo 1).  Then swapped the cutter for the boring head, dialed in to +.030" from just kissing the 0.5" cut, and slowly, slowly at low speed made the final pass (photo 2).  Rinse and repeat for 3 more holes...

It was only just 4 pm by then, so flipped the part over and bored the power piston sleeve bore to about 4.787 (photo 3).  The electronic calipers would not fire up (dead or nearly so batteries), so switched over to my Fowler vernier calipers for measuring the bore.  The steel sleeve provided for this is a rather amazingly round and precise 4.785, with similarly smooth and round i.d., very nice material.  You can see (photo 4) I got pretty close to the mark, probably could have been .001-.002" tighter, but the next step is to loctite the sleeve into the bore, so I wasn't looking for a tight press fit, just a snug slip fit.  These parts came to work with me today, in hopes I can find some old cylindrical mating loctite to set the parts up.

Last a quick family shot of the pieces so far sitting on the garage stairs (photo 5).  Then back inside to warm up with some half-decent Costco (really Jamesons) Irish whiskey (it being Sunday after all) and a steak. :wine1:


Offline Ye-Ole Steam Dude

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Re: Myers Stirling Stove Fan
« Reply #32 on: November 25, 2019, 08:19:05 PM »
Hello Bent,

Looking real good and some nice machine work on your behalf. That is a trick little dude to grab a hold and work with :ROFL:

Have a great day,
Thomas

Offline bent

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Re: Myers Stirling Stove Fan
« Reply #33 on: November 26, 2019, 06:03:37 PM »
Thanks Thomas!