Solid carbide router bits

[Ridgeway]

Can they be overheated to the point they become unsafe or unusable?

I was using a circle jig with a 3/16" solid carbide spiral upcut bit, and managed to create a lot of smoke.  I think I overextended the bit so a portion with no cutting edge was in the wood.  Remarkably enough. that portion had difficulty cutting, but little difficulty getting hot.

When the smoke cleared, the bit had a nice charcoal tint.  I cleaned it, but it is still discolored.  Is it toast like a steel bit, or not?

[fredhargis]

I've done that an didn't have any subsequent problems.

[R Clark]

I think there was a discussion about this subject here sometime in the past two years, but I wasn't able to locate it.

Googling and finding hits on other forums give mixed results.  Some say no issue with carbide, others says the bit was ruined.  However, the links that seemed to indicate that the bit was ruined were vague about whether or not the bit was carbide or HSS.

If it was me, I would inspect the bit closely, sharpen it if needed, and give it a try.

[Ridgeway]

I think there was a discussion about this subject here sometime in the past two years, but I wasn't able to locate it.

Googling and finding hits on other forums give mixed results.  Some say no issue with carbide, others says the bit was ruined.  However, the links that seemed to indicate that the bit was ruined were vague about whether or not the bit was carbide or HSS.

If it was me, I would inspect the bit closely, sharpen it if needed, and give it a try.

thanks - I am going to try some very shallow cuts and see how they go

[Cooler]

I remember ruining a high speed steel router bit (back in 1970) by routing the edge of plywood.  The glue heated the bit and ruined the bit after just one pass. 

I don't know if carbide will break down like that.

This company lists diamond router bits.  There are also ceramic bits, though I have never seen one.

https://www.rockstardiamond.com/we-offer...d-ceramic/

[Ridgeway]

I remember ruining a high speed steel router bit (back in 1970) by routing the edge of plywood.  The glue heated the bit and ruined the bit after just one pass. 

I don't know if carbide will break down like that.

This company lists diamond router bits.  There are also ceramic bits, though I have never seen one.

https://www.rockstardiamond.com/we-offer...d-ceramic/

I redid the cut using shallower passes, and the carbide bit seemed fine.

[fixtureman]

Remember what us CNC guys say a loud bit is a hungry bit speed it up.  You won't heat the bit as much going to fast as to slow.  The chips should be warm and you should be able to hold the bit and not get burned.

[Cooler]

I redid the cut using shallower passes, and the carbide bit seemed fine.

Solid carbide bits tend to be small diameter bits.  Like 1/8" or 1/4" diameter.  Since it is very easy to snap these, I always use shallow passes.  I do that to protect the bit from snapping off, not because of heat though.

[fredhargis]

Solid carbide bits tend to be small diameter bits.  Like 1/8" or 1/4" diameter.  Since it is very easy to snap these, I always use shallow passes.  I do that to protect the bit from snapping off, not because of heat though.

Not necessarily, I have several that are 1/2" as well as 3/8" diameter. These are spiral bits. The fluted solid carbide I've seen tend to e the smaller sizes.

[hcbph]

Can they be overheated to the point they become unsafe or unusable?

I've not heated one enough to burn it so pure speculation.  My main concern would be the solid carbide bit would become more brittle than they normally are.  If that happened, it could throw shrapnel but that's just speculation on my part.