Open the screw hole in carbide inserts?

[challenger]

I have a bunch of kennemetal insert Kc810 and my insert holders use a 4mm screw. The holes in the Kc810 inserts are about. 008 smaller. Any practical way to open the holes?

[chipmaker4130]

Sinker EDM, (hole popper, even a well setup tap burner would work)
There are also numerous diamond 'points' that would do the job if you can find some decent ones.

[nickel-city-fab]

Check out the 1/8" diamond dremel bits at harbor freight

[challenger]

I figured diamond but thanks for the confirmation.

[sarge41]

Have you tried polishing .008" off the crests of the screws? It wouldn't hurt the screw.

Sarge41

[754]

Plus 1 on what Sarge said... do that once.. or just make a screw.

[old mart]

Check whether the hole has an angled front end, you might need longer screws if only the parallel part is opened up.
KC810 is the grade, what inserts are they?
3.5mm is the more common size of screw for middling size lathe tools, although I have 4mm used on some shell mills.

[BCRider]

I think diamond would be pretty slow for removing .008. And there's the risk that if you're going to remove more from one side than the other.

What about making a new holder that uses a clamp down finger? The finger could have a conical feature that fits into the hole and pulls the insert against the back corner at the same time it pushes the insert down firmly.

[MattiJ]

Inserts are probably wrong in a more than one way for your holder if the screw doesn't fit. (could still work acceptably for hobby shop)

[challenger]

A diamond in a dremel tool was a waste of time. I could see right away that it wasn't doing jack.
I think I'll just make a tool holder for these inserts and use the right screw.
So the ANSI screw hole is 3.5mm?
As for the nomenclature I'm still working on it. They were loose and without any label.
My best guess is that these are TAMH2150.
Triangle, 3* clearance,.0005 tolerance, single countersunk screw and molded chip breaker.

[old mart]

Start by identifying the inserts:
http://www.carbidedepot.com/formulas....htm#thickness

[challenger]

Start by identifying the inserts:
http://www.carbidedepot.com/formulas....htm#thickness

That's where I went to get the designation I got???

[MattiJ]

A diamond in a dremel tool was a waste of time. I could see right away that it wasn't doing jack.
I think I'll just make a tool holder for these inserts and use the right screw.
So the ANSI screw hole is 3.5mm?
As for the nomenclature I'm still working on it. They were loose and without any label.
My best guess is that these are TAMH2150.
Triangle, 3* clearance,.0005 tolerance, single countersunk screw and molded chip breaker.

TAMH sounds really oddball combination, never heard and google doesn't know such a combination either. Doesn't mean its wrong but it sure is oddball in that case.


Are you positively sure about the clearance angle?

So these are SINGLE SIDED?

Pictures would be great

[old mart]

TAMH is not likely to be a real designation. One code which will be impossible to judge when the original code is missing is the tolerance.
The size you give is tiny, there's no way they would have a hole of the size you mentioned.

[challenger]

The tolerance is the third letter and most inserts have an M as the third letter. Are you talking about the relief angle? Maybe it's N and not A. I mean it looks steep but I haven't actually measured it so?
Thanks.