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

[Mike Spencer]

ralph> Mike, If you do have it to 1/32 of flat and perpendicular with
ralph> the tup - why not put a piece of 1/8 to 3/16 copper under it to
ralph> let it pound itself into a flat plane.

I don't know why not.  Would that hold up fair to middling, do you think?  
Would a mild steel shim be better?  Worse?

ralph> Copper plate under the die seems like the fastest way to correct it
ralph> (especially if your just trying to get it running to see if it will
ralph> work for you...

That's the idea.

bob> If the upper area is flat, you can use a router with a carbide bit to
bob> machine the lower area.

Yow!  Good idea -- for next time.  I've already leveled the floor of
the dovetail with a cup stone.  Had to take off a lot of metal and
that's why the top surface of the anvil is now too high.

charles> Someone suggested a router with carbide bit , but this would
charles> lower the dovetail floor, not raise it.

Exactly. (That was Bob Bergman.)

charles> ...maybe the 16 guage sheet metal screwed down with
charles> countersunk screws would work best.

So, has anyone seen dies shimmed this way, either with copper or m/s?

charles> ...I would expect that what you want is all of the force of
charles> the hammer transmitted to the floor of the dovetail slot, not
charles> the cheeks.

That's right.  But the working surface of the die extends out over the
cheeks.  If the cheeks of the die stand above the anvil surface, blows
struck such that all the impact is over the cheek will tend to tip
the die, creating hugely exagerated upward force on the opposite side
of the anvil dovetail.

I may be worrying about this more than I need to but the suggestions
and comments are helping my thinking about it.  I took the day off
from working on the hammer to see what you guys had to say and to
think about it.  

Instead, I worked on a "comeback" job.  Years ago I made a pretty nice
firetool set and stand, wood rack with roses, shelf brackets with
padulas [1] and other sundries.  Their house burned down and pretty
much all they recovered from the front 2/3 of the house was my iron
stuff.  Badly rusted and a bit warped but everything is cleaning up
pretty well.  Have to make three replacement parts.

- Mike

[1] His wife is a hooker.  Er, rug hooker, that is.  Hookers call
generic flowers of no particularly identifiable type "padulas".  Not
in my dictionary but I think it's in the OED.

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