lathe tool for trepanning or face cutting/grooving

Mutt said:
I have a Grizzly 4003 I bought new 18 years ago. I Need to make some round gasket punches for punching out fiber washers. I would rather have a one piece punch than a 2 piece.
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Okay, a 12X36 lathe. So, if I understand you correctly, you are looking to make a tool that will punch the inside hole and the outer diameter in one go? If so, that might be a bit tricky to do because the inner punch will interfere with forming the outer part. If I were doing this, I would probably make the tool in two parts.
  • I would turn the outer part to whatever diameter I needed and drill/bore the center, then use a turning tool to cut a sharp outside edge on the rim. That forms the part that cuts the OD of the washer.
  • Then I would drill the center to accept the center part of the punch. I would personally make it a snug press fit and once it is in place, face it to match the outer rim. Then I would drill it and use a counterbore to form the inside edge.
  • Then I would harden and temper the whole thing.
Or, you can make the punch in two parts and make a jig to hold everything in alignment. I'm sure there are other ways to go about doing something like this and you might start another thread so the guys will know you need help designing the tool. A catchy title like, "Help me design a tool" will bring all sorts of responses, I would think.

As far as a specific tool that would make this cut in one go, you might be able to grind a tool like a parting tool but shorter in its vertical aspect to clear the inside of the bore. It would need relief angles on both sides to clear the inner and outer radius but it might work ... never tried it so I'm not sure.
 
yes sir, the former is the way I have always made them, just thought I would try machining one in one piece.
 
There used to be a guy who sold parting tools he ground from 3/8" HSS tool blanks. They were done on a surface grinder and worked well but he no longer sells them, or at least I cannot find them now. They looked sort of like this one: https://www.ebay.com/itm/Parting-Tu...488259?hash=item4d6b86f443:g:guQAAOSwnHZYVFzd

If you were to grind one like this and shorten it vertically so it fit in your bore, then rounded under the cutting edges on both sides so it doesn't rub, it might just work. Again, I haven't made a tool for this purpose so I'm guessing but I suspect it will work for a one-off thing.

Otherwise, a two-part tool would be easier.
 
I think I can grind one of those on the bench grinder . Thanks for the tip
 
You might be interested in this vid by Joe P.
 
Mutt said:
yes sir, the former is the way I have always made them, just thought I would try machining one in one piece.
Click to expand...

How would the fibre washer be ejected once it was cut?
 
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