Ignoramus6711 wrote:
Sorry for a bunch of posts at once. I worked all day long (almost) and
gave 1500 lbs of old junk to a scrapper.

Never had this problem before and I REALLY do not want to screw up.

The head of the Bridgeport CNC mill is attached to the turret with
four socket head cap screws, probably 1/2". They have a 3/8" hex hole.

All my attempts to unscrew them failed. I used a nice Unbrako L shaped
key.

Cannot do it without leverage.

With leverage (pipe) the key twists so much, that I really do not want
to push my luck.

I made a tool today from one 3/8" L shaped key: I drilled a
perpendicular hole close to the end of a pipe, and welded the straight
end of the key into that hole. So I can use the pipe as a lever to
turn the key without as much length to twist.

-. (L key)
pipe |
============|=

^ this end will go into the SHCS

I have no idea how will the key behave after having been welded.

I also have hex keys that are driven with a 1/2" breaker bar or an
impact. I am really afraid that it may somehow break the SHCS, which
would be terrible considering its job (holding the mill head).

Any comments?

i


I would not weld the allen wrench. YOu will anneal it causing it to
bend. Just slip a pipe over it and pull. You will break the allen
wrench before the bolt will snap. Don't hit the bolt with a hammer
directly on the top or you will peen in the hex. If you want to hit it
cut a small length off your allen wrench and put that in and then hit
that. If you apply heat put the heat on the casting but not too much or
there is a slight chance it could crack from heat stress. It is
possible that there was locktite applied to the bolts. Heat will help
release the locktite. A breaker bar and a allen head driver will also
work but make sure it is a good quality tool (a life time warrenty
helps). Impact wrenches suck for taking off bolts unless you have a
large air supply and something that puts out at least 350 ft.lb. Don't
be afraid of breaking off the head of the bolt. If it ever did break you
just put a larger nut over the stub and weld it onto the stub. Two
things will happen, you will have a good grip on the stud, and the heat
from welding will loosen the grip of the stud in the thread and it will
turn out easily after it cools. If you break your allen wrench I have
a case of 3/8 of them made before there were china imports. I got them
at an auction 15 years ago. Its one of the most common sizes on larger
machines.



John