HSS cutting tools

[snoopdog]

So, I tried to grind some tools from discarded reamers, cuttoff, and grooving. My bad for not documenting which end, are reamers harder on the cutting end vs the shaft? This is my suspicion since some ended up cutting great and others absolutely crap

 

[Jim F]

I believe reamers and such are like drill bits, the working part is hard, holding part is not.

 

[benmychree]

I believe reamers and such are like drill bits, the working part is hard, holding part is not.

Yes, correct!

 

[Ecosta777]

Some reamers also have brazed carbide cutting teeth, I would suspect that's the case. If it was hardened a grinder should still grind it no problem

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[compact8]

Probably yes. I have tried cutting drill bits with carbide end mill. The fluted part is definitely harder although its still no match to carbide.

 

[addertooth]

Take a Dremel tool (or grinder) to each end. The smaller, brighter, more complex sparks are the hardened end.
This is the way.

The other method is to take a file to each end. The end the file "skates on" is the hardened end. The end the file can get a "bite on" is the soft end.

Other methods involve more complex tooling, like a Rockwell hardness tester, or a polarizing microscope to look at the grain.

 

[RJSakowski]

Take a Dremel tool (or grinder) to each end. The smaller, brighter, more complex sparks are the hardened end.
This is the way.

The other method is to take a file to each end. The end the file "skates on" is the hardened end. The end the file can get a "bite on" is the soft end.

Other methods involve more complex tooling, like a Rockwell hardness tester, or a polarizing microscope to look at the grain.

High speed steels most often used for cutting tools like drills, taps, reams, end end mills like M2 or M42 do not have branching sparks. They are characterized by a reddish orange spark with no branching. High carbon steels like A1 and O1 have bright yellow highly branched sparks. I have never noticed any significant difference in the spark test between annealed and hardened steels.

A file test is the best way to determine hardness in the home workshop. For more sophisticated testing, there are file set made specifically for the purpose with different degrees of hardness which allow one to better classify an unknown material as to the degree of hardness.

How To Use Hardness Tester Files

Learn how hardness tester files work to determine the hardness of a material, how to use hardness files to determine Rockwell Hardness and more.

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