stuborn material

D

Darrin clause

Joined
Apr 20, 2005
Messages
23
I have some bandsaw material I want to make craft knives from.
I made three knives frome this stuff sofar. When I drill holes for pins the material work hardens before I can finish the hole. I have tried normalizing the material around the hole and it still stay's hard. Iam using brand new cobolt
bits I'll get half way through then it quits cutting. the blade material is M42
HSS made in germany. I was just lucky with the first few but I went through a half dozen bits then switched to cobolt. I need help ? can anyone tell what Iam doing wrong or know a way to aneal this material. thanks
 
Welcome Darrin! Sounds to me like you're doing everything right. I've never heard of this steel but it sounds pretty stubborn. When I spot anneal I use a propane torch over the spot and hold it for quite a while then let it cool very slowly, just gradually removing the heat. Be sure you use a fresh drill bit (sounds like you have this covered too) and use a good lube. I use Cool Tool II for everything. ;) If all else fails you can get a carbide spade bit and let er rip...or even use a diamond coring bit or a diamond burr in your Dremel. I'm sure others with different experience will chime in too. Good Luck! And welcome to Shop Talk.
 
Lemme see, you're trying to drill M42 Cobalt blades with M42 Cobalt drill bits...just might be the problem, huh?
Carbide spade bits are your friend in this case...
You're not going to be able to spot-anneal an air-hardening steel that thin, as it will dissipate the heat fast enough to re-harden it.
 
I have a made a ton of blades from the German M42. If you can stomach the big expenditure for carbide tooling, its great steel and will hold an edge forever. :cool:
 
I've drilled holes in planer blades with masonry bits before, without spot annealling. They were D-2 at 61 Rc, if my memory is correct. I only got about 1 hole per bit, but they were much cheaper than carbide bits, and I can get them at Lowe's. If you're only gonna make a few blades using that M42, the masonry bits might be just the ticket. If your gonna make a lot, carbide is definitely the way to go.

Todd
 
jhiggins said:
I have a made a ton of blades from the German M42. If you can stomach the big expenditure for carbide tooling, its great steel and will hold an edge forever. :cool:
Click to expand...
That's a good recommendation. Where can you get it?
 
Thanks for the welcome.
the spade bit idea work'd great. I baught a glass and tile bit it cut through
like butter. I will have to buy a larger bit for a countersink.
these carbide tip drill bits have all kind's of applications. I wish I checked back sooner the response was a great help. I wonder if this m42 material is available in thicker sizes and where ?

THANKS FOR THE HELP PEOPLE.
 
If you are going to the expense of buying a carbide drill, do not waste your money on a China cheapie. They are junk. Get a good USA Made one for about 3 times the price but 20 times better. Same goes for your carbide inserts in your lathe and mill holders. Don't waste your money on a TIN set of Drills made in China either. A good HSS set made in the USA will do you a better job than their carbide.
 
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