On 4/15/2013 8:32 AM, Ed Huntress wrote:
On Mon, 15 Apr 2013 02:10:06 -0400, Tom Gardner Mars@Tacks wrote:

On 4/14/2013 11:24 PM, Gunner Asch wrote:
On Sun, 14 Apr 2013 20:55:22 -0500, Ignoramus25056
wrote:

On 2013-04-15, Pete C. wrote:

Ignoramus25056 wrote:

On 2013-04-14, Gunner Asch wrote:

https://picasaweb.google.com/1040422...aTurretRebuild

Gunner


I enjoyed it greatly, but I did not understand what you did.

i

He removed a tool changer/toolpost turret from a very large CNC lathe,
took it to a shop to repair a cracked casting properly and then
reassembled it. 9" spindle bore, probably threading oil well drill
string pipe fittings or something. Probably 100HP spindle. Big MF.

OK, I got it, thanks. I usually think that if it cracked once, it will
crack again. But it was a fun project.

i

If its fixed properly..and it was..it wont crack again. At least not
in that location.



It is an ART to repair a casting that won't crack again! A big part of
that is in the pre-heat and cool-down phases of the weld. I've had
mostly good luck but a bit of bad luck. A lot depends on the metal and
the phase of Venus.

Indeed it is an art. When the welding equipment companies, or other
researchers, do a metallographic analysis of cast iron welds, the
results will leave you wondering how it ever works at all. The weld
and heat-affected zone typically is like a layer cake of weirdness.

Anyone who can get good results *consistently* is worth his pay.

BTW, the guy who allegedly was the highest-paid c.i. welder in the
world, an Italian who did nothing else, was hired and shipped in many
years ago by Bill Harrah to weld a crack in the block of his priceless
Bugatti Royale. He did it with O/A and c.i. rod. It worked, even
though it doubtless had oil in the (then) 60-year-old cast iron.

I don't know how he did the pre-heat or stress relief.



He STILL had luck! ...along with the "knack".