Question for a machinist . . .

[Dick Hosmer]

I am thinking of modifying an extractor for my M1882 project. The pin hole will be drilled larger, and a reshaped hinge-bow nut will be set into it - this will achieve the friction-joint with the already bored-out block. I'm thinking of shrinking the two little parts together.

So, when you heat a donut-shaped piece does the hole get larger or smaller? Was thinking that by bringing the extractor to a dull red, and freezing the insert I could get a nice tight fit? Or, maybe just using JB-Weld, or permanent Loctite, would be a better idea?

My tools consist of a drill-press, bench grinder, bandsaw, Dremel, and a large assortment of files!

[lyman]

heat, expand, but it will expand in all directions (so in theory the hole may get smaller)
however, if you ever watched a video of a guy putting togeather barrels or the ring of steel on a wagon wheel, they are headed then cooled to tighten over the wheel,


so I ,, , not a machinist, but did both take machine shop classes years ago and have slept in a holiday inn express in the recent past,,,,, think you are on the right track

[Allen]

Not a machinist either so no help here, just a reminder that heat, such as that from a torch, can reduce or destroy the factory heat treating properties or temper.

Personally, I've never had good luck with JB weld and would try the permanent (red) Loctite first.

One of the places I worked at heated cylinder jugs and pressed them onto cylinder sleeves which were cooled with liquid nitrogen. As the jugs cooled they contracted and as the sleeves warmed up they expanded so the two parts became as one. Likewise for some bolts that hold aircraft engines onto the airframe. The bolts are frozen, installed and torqued, then become very tight after they warm up.

[Dick Hosmer]

Two good replies, thank you both. As to harming the temper, I had considered that, but, for a display piece - never to be shot and seldom even opened - it shouldn't be a problem. Of course, the friction thing is an issue unto itself, and is NOT the first hurdle to be jumped. It just would be cool if I could replicate that function too.

I THINK I now have every last little bit, save for a hammer screw. So, if ANYONE has a surplus M1873 (rounded head) one with a decent-looking slot, I'd like to purchase it or trade something for it. And, to really go out on a limb, if any old codger has a Buckhorn sight marked 28"B (which were on the market, loose, 75-100 years ago) in their cigar-box, I'd surely like to talk with them . . . . .

[butlersrangers]

Dick - You should contact 'FredC' on the KCA Forum. He is an expert Machinist and has a giant shop.

He is very knowledgeable in manufacturing processes and in repairing agricultural equipment.

[Dick Hosmer]

Dick - You should contact 'FredC' on the KCA Forum. He is an expert Machinist and has a giant shop.

He is very knowledgeable in manufacturing processes and in repairing agricultural equipment.

Good idea Chuck, I will.

[barretcreek]

Heating the piece will make it expand the same as if the hole was not there.

[Johnny P]

The outside and inside diameter of the wagon wheel rim are virtually the same, where a very small part with a smaller hole in the middle the OD and ID will vary quite a bit.

You can skip to about 28:00 to watch this guy put a steel rim on a wagon wheel.

https://video.search.yahoo.com/searc...e2&action=view

[Dick Hosmer]

The outside and inside diameter of the wagon wheel rim are virtually the same, where a very small part with a smaller hole in the middle the OD and ID will vary quite a bit.

That's what I thought, hence the question. Actually, the two little parts do not have to be solidified into one to exert the requisite lateral pressure on the block to bind it. That will probably be that last thing I attempt anyhow. Getting the latch housing spot on, so that the bayonet functions properly will be the tricky part. Several interrelated dimensions need to be exactly right for the whole thing to work, and I have no mill, special cutters, or fitting jigs - it's all going to be file-and-try, file-and-try, etc. . . But, it will be FUN!