Who profiles with a plasma cutter?

R

Richard Barrett

Joined
Sep 6, 2007
Messages
4
I saw a few distant posts from folks asking about profiling with a plasma cutter.

Does anyone here actually use a plasma cutter for rough profiling, then anneals their blades? What are your experiences?
 
The guys at Baltimore Knife and Sword use this method almost exclusively. Assuming that you don't dawdle while making the cut, just make it a bit oversized for your design and grind the HAZ off. No need for annealing. I know the guys at BKS use a CNC plasma table and usually end up with a HAZ of ~1/16" or so.

-d
 
I just bought a 520DX Plasma/TIG/MMA a month ago. I have already sent it back because it died after twenty minutes. I'm not saying that they won't work, just that mine was bad. At $20 per cut, I can pay the local shop to profile a lot of them for me before I cover the cost of a unit. Plus, it's not just the $450 for the unit, it's another $100 in cabling and $86 for a bottle of argon. 10-3 wire is not cheap, nor are L6-30P sockets and plugs.

As for the HAZ, I'd say that 1/16" is about right on the one knife I cut out. A couple minutes with the 36 grit belt and that was gone.

If you get one, look for "Pilot Arc". With normal units you touch the wand to the metal to ignite it. With a pilot arc system, it self-ignites when you hit the trigger.
 
since i use john deere disks that rockwell around 56 to start with, i have no choice but to get them plasma cut or cut them out with my right angle grinder. the plasma torch i use belongs to a buddy and it uses air and not gas. the tips do wear out after some use and need replaced which is the only expense with his setup. i can cut up 6 strips in a few minutes from a 17" disk.
 
I have used a plasma to cut out some blades. As far as a "normal" plasma cutter. Well the "normal" ones DO NOT touch the torch to the metal to ignite it. Those are the cheap "offshore" ones. I have used miller/hobart, thermal dyn, hypertherm, and lincoln plasma cutters, and all of them ignite when the trigger is pulled.
 
...at 60,000 psi+ - its called a water jet cutting machine. Water makes cutting profiles simple, cool, clean and you do not alter the molecular structure of the steel.
 
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jaymeister99, it can harden the edge but not as much as a cutting torch which can harden a wider area.
 
richard j said:
jaymeister99, it can harden the edge but not as much as a cutting torch which can harden a wider area.
Click to expand...

Why heat the steel up to a molten state in close proximity to the cutting edge of the blade when you don't have to? Everything discussed thus far is inferior to profiling with water.
 
I think I'll run out and buy me one o' them waterjets tomorrow!
Think I can get one fer $500?
 
BMK said:
Why heat the steel up to a molten state in close proximity to the cutting edge of the blade when you don't have to? Everything discussed thus far is inferior to profiling with water.
Click to expand...

is that what you use for the sawzall blades?
 
Plasma, particularly CNC, should work fine- as mentioned, just clean back from the kerf a little when finishing the profile so as to remove the heat affected zone. Then do whatever the heck you want with it.

Don't know if you know this, but the IMO the words of a particular individual in this thread should be taken with a huge grain of salt. If you research, (not deeply, either) you will find ample evidence to support this claim. You probably know this already.
 
no bill, you are a well respected member here who has probably forgot more than this person who salem is talking about will ever know :D. i wonder what website this person is quoting his information from :rolleyes:. it seems his first reply did not suit him so he edited his post ;):D
 
There is no need to purchase a machine. The water jet machine service that I use costs from a few dollars a blade to 10 or more dollars/blade to profile depending on how many blanks are being cut.
 
BMK said:
Why heat the steel up to a molten state in close proximity to the cutting edge of the blade when you don't have to? Everything discussed thus far is inferior to profiling with water.
Click to expand...

Why? Because you can get one for $400. How much does a waterjet cost? Is it portable and can I take it to Dave's to use it? Sure, the waterjet may be nicer, but most of us don't drive a Ferrarri, either.
 
BMK said:
...at 60,000 psi+ - its called a water jet cutting machine. Water makes cutting profiles simple, cool, clean and you do not alter the molecular structure of the steel.
Click to expand...

First of all, steel does not have a molecular structure, it has a crystalline structure. :
Learn, THEN post

-Page
 
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The point was that you change the steel but I can understand why the lesson in semantics was focused upon.

I always thought atoms combine to form molecules. Crystalline sounds esoteric and "arcane". Thank you for the lesson that will help me make a knife that functions better.
 
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