Gas check maker -- need help please.

[nhrifle]

I am in the process of making a gas check maker. The main forming/punching die is an old Lee bullet sizing die that has been repurposed for the project. I have bored it out to the necessary sizes and have the disc punching rod turned. I cut the slots in the die to feed the strips of raw material through to punch the discs from, but I need to widen them internally without removing any external metal. The die is hard enough that a file just skips over it and a hacksaw just polishes it. Any ideas for a small abrasive cutter to open the slots inside the die without affecting the outside would be appreciated. My Dremel wheel and arbor were used to cut the slots initially.

 

[pdentrem]

Can you get a diamond disc in there? There are diamond covered cutoff disc available. Or use diamond burrs.
Pierre

 

[nhrifle]

Can you get a diamond disc in there? There are diamond covered cutoff disc available. Or use diamond burrs.
Pierre

Nothing like that available locally. Do you know of a source?

 

[pdentrem]

Lee Valley
http://www.leevalley.com/US/home/Search.aspx?action=n

Rio Grande
http://www.riogrande.com/Search/Diamond-burr

We have dealt with both.
Pierre