Plasma cutting blade stock

K

KBeck

Joined
Sep 11, 2009
Messages
19
Hello everyone. I recently bought a plasma arc cutter for in my shop and I'm rapidly falling in love with this thing, it's a great toy! I've yet to try it on blade stock (O1, 440C etc.) however. I'm sure I could rough out a knife in a matter of minutes with this thing but I'm a bit concerned that the intense heat may somehow harm the stock.
So I was wondering if anyone else uses one of these cutters or if there is anything I should know before I try it out on my good steel.
Any help or comments are always appreciated.
 
i have to get all of my blanks cut with a plasma torch since the steel rockwells at 56rc. you have to heat treat the steel anyway so the small area that gets heated wont matter. i wouldnt use it on air hardening steel.
 
Hi K, from what I understand, using a torch, plasma cutter or a laser is perfectly acceptable for cutting your profile as long as you plan for a HAZ ( Heat Affected Zone ) around the perimeter.

Others here on BF might be able to give you an exact HAZ dimension for your plasma cutter. Just off the top off my head (for 1/8-3/16" stock) I would think that adding ~ .060 ( 1/16" ) to your planned blade edge would be sufficient. Other areas, like the handle, the spine, etc., I would think you should be able to get away with just allowing for clean-up ( ~ .015-.020 ).

It is my understanding that a laser has less of a HAZ than your plasma cutter while an Oxy/Acetylene torch has more.

If you were to use a waterjet to profile, (someone like Dave at Great Lakes Waterjet) you would not need to worry about a HAZ.

Check with someone who knows the specifics first though.

FWIW, on my stock removal blades I use a bandsaw to rough profile, then go to my KMG for finishing, so take this info with a grain of salt ................ ;)

:thumbup:
 
I'm a complete noob here, but I'll relate my experience FWIW. I took a knife making class at the local vo-tech last year, and the bandsaw we were supposed to use to cut our profiles was unavailable, so we used a plasma cutter. We were using O-1, and it work hardened in places, and I mean REALLY hardened. It wasn't a real problem; it just meant we had to re-anneal before grinding.

Rick DuBois
 
Sounds good to me, now I can't wait to try it out. Thank you everyone for your input.
 
Plan on removing 5-6 thou around the perimeter of the blade to get rid of the heat affected zone. It might be a little more if you are not using a water table to help cool the moterial as you cut.
 
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