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

[theforge@mailman.qth.net]

Mike Spencer wrote:

>Charles wrote:
>  
>
>>Personally, for what you have left, I would use a 16 inch nicholson
>>double cut file.
>>    
>>
>
>I use small files and a 10" mill smooth or mill 2nd cut a lot.  I
>don't think I even have a big mill/flat bastard.  Cut down two
>ca. 5"x12" surfaces by 1/16 or so?  Seems like a whole lot of
>filing. Maybe I've underestimated the power of big, coarse files
>
Didn't catch that it was two 5"x12"  areas.  I can see why you are 
looking for powered alternative.   For some reason, I was picturing it 
an inch or two wide.   The problem with filing really wide flat areas  
like yours  is  there are too many file teeth in contact.   I have a 
couple of large files with a VERY slight belly side to side in them that 
work in this mode, but have not seen them sold new.   I have also used 
vixen files in a carrier that will put a slight belly end to end in 
them, but have only used these on mild steel.  I would expect cast iron 
would take the edge off the teeth of a vixen pretty quickly.    In your 
case, maybe the 16 guage sheet metal screwed down with countersunk 
screws would work best.    Someone suggested a router with carbide bit , 
but this would lower the dovetail floor, not raise it.   Typically, 
cleaning up the anvil would result in the top surface being removed, 
with the dovetail floor too high, in which case that would be a great 
way to go, but you seem to have the  opposite problem.   Someone with 
more experience of large power hammers should correct me if I am wrong 
here, but I would expect that what you want is all of the force of the 
hammer transmitted to the floor of the dovetail slot, not the cheeks.  
Unless the top surface of the anvil interferes, the wedges will force 
the die into closer contact with the floor of the dovetail.  This being 
the case, you may want to use an even thicker spacer in the bottom to 
insure that the primary contact is on the floor of the dovetail.

Charles