Question for Nate

rodriguez7

rodriguez7

Gila wilderness knife works
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Feb 1, 2009
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whats going on Nate, so I'm starting to make my own knives, rather primitive in comparison to you. I'm ordering a few small plates at a time, and cutting out the shapes with an angle grinder. Which is very time consuming. I do not have a water jet anywhere near me. Just my local welding shop. I have access to possibly build some cad drawings and take them to my local shop and have them cut with a plasma, I was reading in another thread that it's possible to ruin a blade, by I guess burning up the carbon. I think you had said, that after a plasma , there's about an eighth of an inch of leeway. Possibly. Am I better off just sticking to an angle grinder for the time being? Or drawing up my design with some leeway built into it, and grinding off the leftover scale?
 
A few small things if I may.

This would probably work out well in the general knifemakers questions subforum, but:

Due to the heat produced, you will likely have a harder skin around the exterior, just below the face of the cut, that will he harder to get through than the rest of the bar.

You also can end up having the carbon burnt out of the very face of the cut, but that would have to be ground to profile anyway.

I do not know the depth of the heat affected area, but I would be willing to bet that it would come down to the thickness of the sheet/bar and the alloy, more accurately, whether it is air hardening or not.

There are plenty of companies that will water jet a schematic sent to them as long as it is in the correct format.
Have your file drawn up, and email it out for quotes.
Include the material type, and note that each additional hole/cut/puncture raises the price, since it slows the process.

I am looking forward to hearing what Nathan has to say on the topic too.
 
Thanks for the insight. I just figured I would ask Nate, I like his knowledge more than most
 
The heat affected zone from plasma can be small or thick, depends on variables, but it's never zero.

Complex steels with long austenitizing times pin grain boundaries with carbide. That carbide will be dissolved from heat for a short distance near the cut and the steel will experience grain growth from the cut and subsequent heat treat. It may be .002" or .020" but it will need to be removed to good steel.
 
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This would be for 3v. Where I live it's hard to find certain services. I'm trying to figure it out
 
Nathan the Machinist said:
The heat affected zone from plasma can be small or thick, depends on variables, but it's never zero.

Complex steels with long austenitizing times pin grain boundaries with carbide. That carbide will be dissolved from heat for a short distance near the cut and will experience grain growth from the cut and subsequent heat treat. It may be .002" or .020" but it will need to be removed to good steel.
Click to expand...

Ugh.. so fu$king cool. So.. fu$king..cool.

This is like asking Nikola Tesla about alternating current..
 
Feel free to correct me if I'm wrong..

The plasma cut is going to mess up the carbide structure near the cut. It will subsequently need to be removed to uncover uniform grain and carbide structure.
 
The heat will blow the grain. You probably don't want to go through the process to reset that grain and will need to peel off the HAZ to good metal. 1/16" should do it.
 
Sweet, thanks for your help Nate. It just saves some time, if I have my buddy plasma cut some blanks for me. I'll give it some leeway, and see what happens.
 
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