Router bits...burned?

[Stwood_]

   

   

[daddo]

High temps doesn't affect the properties HSS. You can heat it to red hot and it will retain it properties. HSS is stronger from breakage than harder and brittle Carbide.
HSS doesn't like high speed cutting- carbide does best at higher speeds.

HSS is sharper than carbide.

Carbide doesn't like plywood or MFD.

I doubt heat has hurt either cutting wood, but both could be dirty and dulled.  I use both on the metal lathe- each has it's own goods and bads.

[handi]

That is not quite right.

Carbide cutting bits are typically a combination of particles of tungsten carbide (produced by carburizing  fine tungsten particles) and a base material that is usually either particles of cobalt or nickel alloys.  These particles are then hot pressed and heated (sintered) to form a solid product.  This is generally refereed to as powder metallurgy. 

The resulting product is not only stronger than HSS, but should withstand high temperatures better than HSS.


There are no carbon particles, the carbon atoms are joined to the tungsten atoms.

I stand corrected about the compound, but my information is still correct: Carbide tools are far less heat tolerant than HSS, and HSS takes a finer edge than a Carbide so it cuts wood much finer.

Carbide certainly wears longer AS LONG AS IT IS NOT OVERHEATED, but most bits are destroyed by heat in my 30 years of experience.

[Richard D.]

Then why does the "black" clean off with solution and light brushing?

[KyleD]

I stand corrected about the compound, but my information is still correct: Carbide tools are far less heat tolerant than HSS, and HSS takes a finer edge than a Carbide so it cuts wood much finer.

Carbide certainly wears longer AS LONG AS IT IS NOT OVERHEATED, but most bits are destroyed by heat in my 30 years of experience.

My experience does not jive with yours. I know it is with different uses though.

I have brazed old carbide bits onto drill rod to make specialized boring bars for metal lathe turning. 
This involves heating the carbide up to a dull red. 
The carbide came off an old saw blade. 
A touch up with a diamond paddle and the bit is good to go.

[handi]

My experience does not jive with yours. I know it is with different uses though.

I have brazed old carbide bits onto drill rod to make specialized boring bars for metal lathe turning. 
This involves heating the carbide up to a dull red. 
The carbide came off an old saw blade. 
A touch up with a diamond paddle and the bit is good to go.

Interesting! I suspect that the rapid dulling I have found is due to heat and friction combined. In other words, simply heating it will not damage the edge, (Carbide tips are braised after all) but heating under the stress of cutting will damage the edge.

[sailor 56]

Interesting! I suspect that the rapid dulling I have found is due to heat and friction combined. In other words, simply heating it will not damage the edge, (Carbide tips are braised after all) but heating under the stress of cutting will damage the edge.

It you are cutting metal/steel with carbide tooling and there is no lubrication (which also serves as coolant) I suspect the carbide would fail quickly not due to heat but because of the brittle nature of the carbide.  Small chips could form on the cutting edge due to vibration.

Steel changes color due to overheating...not sure carbide does the same.

[KyleD]

It you are cutting metal/steel with carbide tooling and there is no lubrication (which also serves as coolant) I suspect the carbide would fail quickly not due to heat but because of the brittle nature of the carbide.  Small chips could form on the cutting edge due to vibration.

Steel changes color due to overheating...not sure carbide does the same.

I was taught by 40 year career operators how to run a metal lathe. I was told to pay attention to the color of the metal chips coming off the lathe. High speed steel tooling could be colored as hot as straw but that color would shorten the tool edge life. With carbide tooling you know your in the zone and using it right when the chips come off the lathe blue.  Straw denotes around 350 degrees F. Blue is around 475 degrees F.

Worn carbide tooling is for the most part not visibly chipped. It can chip or completely disintegrate as its brittle nature indicates but not as often as one may think. The edges of a worn bit appear discolored and slightly dulled under magnification. This observation supports Handi though I would think the small bit of burning on a wood bit should respond well to sharpening with a diamond hone.