I am inlaying some very fine gold wire and I cannot find a steel that will hold a fine enough point for undercutting the lines. I have GRS x7 ,GRS -carbide and some plain cobalt high speed steel blanks. The point must be very fine , about like a flat needle point. with a 30 or 45 deg angle. The carbide is working the best but will only hold up for about a dozen cuts. the GRS x7 doesn't chip often but the tip bends or blunts up real fast.
Anybody know any tricks??

Jerry Huddleston
11/4/2007 1:45:53 AM

Hi Jerry,

You don't say what you are trying to undercut or what method of undercutting you are attempting to use.
Also, what size of wire are you trying to inlay?
Give a little more detail please.

One method I have used to inlay wire down to .003 is to just scribe the walls of the cut with a miniture carbide scribe.

I believe Sam Welch also uses this technique sometimes.

Best regards, John.

John Barraclough
11/4/2007 9:27:00 AM

John. I was hoping you would reply. The wire is .06 . The metal is a 44 S&W mag. cylinder. It Doesn't seem very hard. I'm cutting it easily but it's not real soft either. It is tough but not hard. I don't quite get that scribe method. I have been driving the chisel into the wall of the cut. The graver I am using is a 90deg. belly 60 deg face 22 deg heal. so it is a 90 deg V bottom groove. J.H.

Jerry Huddleston
11/4/2007 3:41:42 PM

Hi Jerry.
For my fine inlay borders I mostly undercut with a very small chisel in the shape of a flat screwdriver but with just the last .020 sharpened.
For the size of wire you are using it would be ground so that the cutting edge was.010-.012 wide. Made from 5% cobalt graver material.
This is held just above the bottom of the groove and held at about a
55 degree angle while being driven lightly into the wall of the cut.
The other wall is treated in the same way and the gold is seated with a brass punch.
To use the scribe method make a small carbide scribe.
Put the point into the groove and holding the scribe like a pencil and applying some forward pressure draw the point along each wall just above the bottom.
I then put some "pin pricks" in the bottom of the channel to stop the gold from "tootpasting" along the cut as it is seated.
Bye the way, Jerry I cut my lines for very thin wire inlay like yours with a #1 or #2 ongellete.
It's much easier to keep the finished line an even width.
Another time, give it a try on a practice plate. You might like it.
I'm sure others have different ways but this works for me.
Best of luck with the project. John.



John Barraclough
11/4/2007 4:18:49 PM

Thanks John. I'll try that ongellet. And the scribe method. J.H.

Jerry Huddleston
11/5/2007 12:42:19 AM

Jerry, on the really fine lines it may be easier to hand push the undercutting chisel. Much less stress on the chisel and you can feel what is going on. S

Sam Welch
11/5/2007 7:34:28 AM

Thanks . Sam.

Jerry Huddleston
11/5/2007 11:40:53 AM

ho, jerry- i couldn't inlay to save my hide- but i think a 90 is too fat- or wide. a very narrow knife or onglette shape is more whats needed.

J.D. Swartzfeger
11/18/2007 1:22:16 AM

Hi Jerry
If you have en old bold tungsten bur, you can very easy reshaped it on a diamond wheel. For finest deep line best way, for my sens, is onglette.

Dmitriy Pavlov
11/18/2007 11:54:07 AM