Plasma cutter on blade blanks?

[jimbowie7]

Anyone tried using a plasma cutter to cut out the blank?

Would it create too much heat?

Thanks!

 

[Alpha Knife Supply]

Grinding off the HAZ (heat affected zone) is a pain.

 

[F. Allin Kahrl]

I've got a small one that I've been playing with. It works great on materal 1/8" and under, gets more challenging on thicker stock. As Chuck said, it leaves a zone of very hard steel next to the cut which must be ground off (files won't touch it), but I think it will still ultimately be a good way to go since I end up grinding my profiles anyway.

-Allin

 

[harreymudd]

Dose anybody know of a small jobbing shop with water jet cutting service? Rather than plasma cutting there is no heat involved in the process resulting in no hard edge to grind threw.

 

[Ed Caffrey]

As Chuck mentioned... the heat effected zone of a blank that is cut out with a plasma cutter is a bugger to grind. Approx. 1/16" of material is hardened during the process, and you can chew up a lot of belts getting rid of that 1/16".

Waterjet outfits usually work on quantity. The less you have done the more expensive it is, and the more you have done, the cheaper it is. I have a very small waterjet cutting outfit in my town, and have visited them a couple of times asking about having parts waterjet cut for damascus billets. They are just crazy on their setup costs! The last time I went to visit them I wanted to get 6 pieces of 2" thick mild steel cut into the design of a Knight chess piece......they wanted $500 for a setup fee, and then were going to charge me $125 EACH for the pieces!
On the other hand an outfit like Admiral steel will laser cut knife blanks fairly cheap. I checked with them on some small knife patterns at one time, and found I could get 100 cut out, with them providing the steel, for less than $3 per blade.

 

[HOGCAT]

How about annealing it after the plasma cutting?

 

[mete]

You're right Hogcat. First the plasma gets the edge above the hardening temperature and so certainly with the more complex steels you harden it and risk cracking. Just like welding complex steels you should preheat first ,400-450F .Then after cutting anneal .

 

[Raymond Richard]

I've got a bunch of old circular lumber mill saw blades I plan on getting cut with a friends plasma cutter. I just want the steel cut in usuable widths for forging and also to be used in damascus billets. Will there be any problems leaving the cut edge alone going in this direction?

 

[Alpha Knife Supply]

We work with several different waterjet companies. If you want more information call us.

Ed is correct about the setup costs. If you are going to do a run of many pieces the setup is spread out over the entire run. A few pieces can get very expensive.

Ray, I would have the circular saw blades cut by waterjet. The waterjet company can stack the blades so several are being cut at the same time. A 2" stack is easy for them to cut. Tell the waterjet company you want to do a fast cut. It is much less expensive. I would not cut the circular saw blades by plasma. I don't know if the HAZ can be annealed out, and I would not take the chance.

 

[mlovett]

I've had several conpanies that have both Lazer and W-jet, suggest lazer. However I have been concerned about a tempered edge as in Plasma. Any thoughts. Thanks Mike

 

[Stacy E. Apelt - Bladesmith]

Laser cutting leaves no hard edge or slag.The steel is vaporized,not melted .I get my blanks cut by Admiral.They look like they were punched with a cookie cutter.Best thing is I can order more and know that they will be exactly like the last batch.