On Tue, 09 Apr 2013 16:17:24 -0700, wrote:

On Mon, 8 Apr 2013 13:28:15 -0700 (PDT), Stanley Schaefer
wrote:

On Apr 8, 2:18*pm, John M
om wrote:
The fixed cast iron nut on the screw drive of my Columbian cast iron vise has
broken off & is lost now....What is the best repair?

--
posted fromhttp://www.polytechforum.com/metalworking/the-fixed-nut-is-broken-on-...
using *PolytechForum's *Web, RSS and Social Media Interface to
rec.crafts.metalworking and other *engineering *groups

For repair, get a new vise. Or maybe used. Not much can be done TO
repair one, at least so it'll hold. If you try to braze it, it'll
just make the surrounding cast iron brittle and it'll crack. Somebody
with a fully equipped shop could probably turn up a steel nut and
figure out how to fasten it in there so it wouldn't spin, come out or
break the rest of the casting, that wouldn't be me... By the time you
finish dinking around with it, you'll have the cost of another vise in
the time spent. Need a boat anchor, you've got it.

Stan
Greetings Stan,
I have a cast iron vise that I brazed back together over 20 years ago
and it gets hard use in my shop. I don't know why torch brazing a vise
would make it brittle. I have tig brazed cast iron and it did get
brittle in the HAZ, but every time I have used a torch to braze cast
iron it has worked well and the cast iron has not become brittle.
Eric

I suggest that it wasn't the cast iron that became brittle it was the
steel weld filler that absorbed carbon from the cast iron that became
brittle.

I seem to remember that specialized "cast iron welding rod" contain a
significant percentage of nickel to alleviate the problem.

Brazing, of course, doesn't exhibit the problem probably due to the
relatively low temperatures and the fact that adding carbon to brass
doesn't seem to cause it to become brittle.

--
Cheers,

John B.