[TheForge] Advice? Air hammer die and anvil fit-up

[Mike Spencer]

I'd like to have suggestions about how to deal with setting up the die
and anvil on my 300# air hammer.  At the risk of being long-winded,
I'll explain the situation.

This is a hammer with a separate, ca. 2.5 ton cast iron anvil that is
already in place.  Previous owners of the hammer ran it with a loose
die, wedges it with crude chunks of torched off scrap and, at one
point, tried to weld the steel die to the cast iron anvil.  The anvil
was a mess.  Worn, beat up, out of square, swales in both the surface
and the floor of the dovetail, not to mention puckers and pits all
around from the failed weld attempt.  The crappy wedges were welded in
place.

I have it ground down to pretty flat -- within +/- 1/32 -- and
perpendicular to the tup bore.  But now the floor of the dovetail is
ca. 1/16" lower than the anvil surface.  The die, which weighs maybe
140#, now hangs on the anvil surface but there's ca. 1/16" of space
between it and the floor of the dovetail in the anvil.

    Would it be reasonable to put a piece of 16ga. sheet under it and
    expect the die to bed itself into the steel?

    Is it really neccessary to grind another 1/16" off the anvil
    surface?

    If I did that, would it fast and (relatively) easy to use a
    hand-held belt sander and, say, a 40 grit Norzon belt to hog off a
    16th?

It's real slow and tedious to get an even, approximately flat surface
with a angle grinder using an abrasive disk and a cup wheel and a jury
rigged gauge hung from the bore.

I think if I *did* grind it down to an eyeball fit, I could get it
even better by lapping it in.  I have the worm gear drive from an
automatic coal stoker that outputs about 6 rpm when driven with a a 3450
motor.  I was thinking of making a little crank and con-rod, mounting
the rig next to the anvil and connecting the con-rod to the die.  I
could slather it with coarse lapping compound, then go off and leave
it run for half a day and the die would be ground back and forth on
the abrasive maybe 2" in each direction (just under its own weight).
The steel die is pitted but pretty flat and true.

On the other hand, if I stuck some 16 ga. sheet under the die, I
couldn't very well do that.

The goal here is not to spend too very much money and time getting
this thing together utill I find out if it's going to work.  On the
other hand,  I don't want to leave bits unfinished that will
neccessitate taking the thing apart again later to get it right.

Mutter, mumble.  Any suggestions, coments or pointers  welcome.


- Mike

-- 
Michael Spencer                  Nova Scotia, Canada 
                                 
mspencer@tallships.ca            
http://home.tallships.ca/mspencer/