Re: Half nut restoration


gorvil
 

Thanks for the reply Ed,

My thinking was along the same lines as yours. I bored out the old
threads to about .830 and planned to silver solder a sleeve turned
from a bronze casting sprue. The extra material would hold the two
halves together during the threading operation. A hack saw and a
broken rusty file would do to separate the two halves and clean up the
saw kerf.

I purchased a tandem Acme tap on E-bay a couple of months ago and I
have been itchin to try it ever since.

Glen Reeser....

--- In southbendlathe@y..., edward4583@a... wrote:
Glen,
I posted on this around January. I had mine built up with WELCO 14
BARE
nickel silver alloy. I just got my 9" running last week and the
halfnuts I
rebuilt with this procedure are as good as a new set if not better.
Here are
a few added thoughts in addition to the article.
1. I did all my work on a Bridgeport mill. This procedure can be
done on the
lathe as in the article but the mill setup is sturdier
2. I bored the original threads out to .85 dia. I reasoned this
would leave
.05 of alloy to act as a "base" for the threads.
3. The halfnuts appear to be made from a single casting and split
down the
middle with a 1/8 cutter after all factory machinery is complete.
When I
sized and cleaned up the silver solder I left the center portions
heavy so
there would be .005 or less between the two nuts when in the
fixture. (In the
fixture the nuts are in the engaged position on the lathe.) In
hindsight I
believe this step was the basis for my threads coming out as good as
they
did. I'll explain. I purchased a new tandem acme tap for this
project and
during tapping I had to add clamps over the threaded portion of the
nuts as
the casting would flex away from the tap. I tapped about 1/4 turn
and backed
out. I did this while advancing 1/8 to 1/4 turn each time. By having
a full
diameter of metal around the tap I experienced none of the
"breakout" that
would have been felt with the 1/8" gap between the nuts. Also, you
can
purchase a single stage acme plug tap for about 1/3 the price of a
tandem.
Don't even try to do this with an acme plug tap. I think the nuts
would break
from the forces required to remove all the metal with the single
thread
former on the plug.
I have spent the last year rebuilding my 9" and at some point in
time I plan
to post pictures in the files sections so the group can see my toys.
In this
was to be pictures of these nuts and the fixture. If you have any
questions
feel free to contact me.
Keep turning!
Ed
9" Model

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