Which bronze for K&T table nut?

Blazemaster · Dec 31, 2014

I have searched and searched and can't seem to come up with an answer on which bronze to use for this nut. It is for the x axis table nut. I have pretty much narrowed it down to 954 aluminum bronze, or 932 (660) bearing bronze. I have found threads where folks recommend the 932, and others that say only 954 will do. I have also found threads that say 954 is too much and will wear the screw. Does anyone happen to know what alloy K&T used?

I managed to remove the old nut, which was not easy. I have never seen 954 that I know of, but I have a chunk of 932 that I bought a while back to make a bushing and thought I would compare the two. The K&T nut looks more red to me.

I am sure either will work from their descriptions but I would like to use the right material. They are roughly the same price.

I would also like to find someone local to help make this nut for me, if possible.

Thanks!

cmike · Dec 31, 2014

Cincinnati used AMPCO Bronze #18. I will looked up the print for the Cincinnati table half nuts and make sure. If your going to make them, you may want to trace the threads on the screw and see how much wear is in the center of the screw comparing the ends. You can trace the threads and fit your nuts too them.

http://www.ampcometal.com/en/index.php?page=a18ext

Good Luck

johnoder · Dec 31, 2014

If I had one to make I would use 936 simply because it is the easiest to machine. I lean towards this approach to longivity - these machines will never see the early forties again by any stretch of the imagination. (there is something behind that statement - I read history. As of the middle of summer 1945 we were shipping 600,000 tons a month just to support the Pacific war. That is one giant pile of stuff to get made in 30 days.)

beckley23 · Dec 31, 2014

My experience with Ampco 18 is good as long as I didn't have to single point thread it. Threading was tough, liked to chatter.
I recently did a job needing 954 Alum-Bronze, make a new TS nut for Clausing-Colchester IIRC it was 7/8 10 TPI LH Acme with a .200" lead. I was dreading it, but it was probably one of the easiest single point jobs I've done. Still got 11"+ of 3" D material sitting on the shelf.
Harry

WHHJR · Dec 31, 2014

What machine is this for? I have a 2CH nut from a Monitrol machine in relatively good shape.

2¢

WILLEO6709 · Dec 31, 2014

ampco 18 = cda954

I made a nut with that for a Cincinnati Gilbert HBM. Its not too bad to machine as long as you are not tapping.... its easy with carbide but hss taps pull HARD.

If its not a daily runner go the softer stuff

locoguy · Dec 31, 2014

Be sure to follow cmike's advice bout truing up the male thread, prior to machining the new nut. And remember when grinding tool for chasing nut, that you are to be cutting the opposite form as the screw. Just think about it.

[486] · Dec 31, 2014

locoguy said:
Be sure to follow cmike's advice bout truing up the male thread, prior to machining the new nut. And remember when grinding tool for chasing nut, that you are to be cutting the opposite form as the screw. Just think about it.

That's some good advice.
I'd have ground a toolbit to fit in the leadscrew. Still might, if I forget between now and then, heh.

Blazemaster · Jan 1, 2015

This is for a 2k plain, not sure if the 2ch is the same size nut, but its a bigger machine by about 2k lbs.

It won't get used daily for wartime shifts, maybe a few times a week at most.

kpotter · Jan 1, 2015

I have made new nuts for machines but sometimes when they looked like they would be a royal pain in the ass I used devcon bronze and recast the threads. this is far from ideal but in many cases this fix was fine. Sometimes it actually worked better than a new nut because the screw was so worn that a new nut wouldnt help much.

KTJman · Jun 26, 2020

Bronze for nut.

Blazemaster said:
This is for a 2k plain, not sure if the 2ch is the same size nut, but its a bigger machine by about 2k lbs.

It won't get used daily for wartime shifts, maybe a few times a week at most.

We bought this material in long bars. It was extruded with a hole in it. Came in several sizes. (When K&T was shutting down all metal stock was being scrapped. I bought some and made a really nice half pounder black powder cannon. Weighs about 180 lbs.) It's 660 bronze.

johnoder · Jun 26, 2020

It's 660 bronze.

Also known as C932 Bearing Bronze

dana gear · Jun 26, 2020

johnoder said:
Also known as C932 Bearing Bronze

We have ended up with a bunch of C932 out of the Hunters point navel ship yard in the S.F. bay.
Some was pretty large diameter. all of it was cored.
We used it on a repair of a older mechanical Bantam press brake that had jack screws on the lower apron for die opening adjustment. They can see a decent load when coining operations, it's been a number of years with absolutely no problems.
These jack screws ramp up and down all the time.

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Which bronze for K&T table nut?

Blazemaster

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cmike

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johnoder

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beckley23

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WHHJR

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WILLEO6709

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locoguy

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[486]

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Blazemaster

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kpotter

Diamond

KTJman

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johnoder

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dana gear

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