On Thu, 17 Aug 2017 17:09:57 -0500, Ignoramus8462
wrote:

I bought a used industrial machine (a huge pipe threader).

It is a super nice machine in all respects and was rebuilt in 2007.

However, the reason why it was sold for nothing is that the cast iron
transmission case in it is cracked due to a past accident.

The picture, with the crack highlighted, is he

http://igor.chudov.com/tmp/trans.jpg

You can visualize this as a rectangular casting with one corner broken
off. The three highlighted areas are in fact one crack separating only
two pieces.

The size of this is about 1x1x2ft.

What I need to do is put it back together. Put in funny terms, I could
take these pieces, clean them and "glue" them together, the question
is how.

Real glue, obviously, would not work.

Nickel welding would likely not work well either.

It would seem that the pieces could be taken out, really cleaned up,
pushed together, heated red hot, and brazed with brass.

Does that make any sense?

What would be the best approach?

Thanks

i

We once repaired a large pipe threading machine that was cracked. We
veed out all the cracks and made some alignment rods to keep the
bearing holes aligned and then heated it to a dull red in a heat
treating oven. The cast iron housing had absorbed considerable oil
over the years and it took a while for that to burn out but when the
smoke had ceased we hauled it out of the oven and brazed it while
still at a dull red and then pushed it right back in the oven and
reheated it and then slowly cooled it over a 24 hour period.

From memory it took, perhaps, 2 man days for the machine shop work and
an additinal 2 - 3 days for the welding shop. Call it, say 5 man days
for workmen plus overseeing by a machine shop supervisor and a welding
shop supervisor, but we did end up with a usable machine.

I was in the Air Force at the time so cost was not even considered and
from memory we did the project more as an "can we do it" exercise
rather than a "we gotta fix it" job.
--
Cheers,

John B.