Plasma Cutters

Ferret

Ferret

Joined
Jan 20, 2000
Messages
1,749
Metal cutting bandsaws are freaking hard to find here (well, cheap anyway)...has anyone tried plasma cutting their blades? How about liners? TIA
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Ferret, sorry, this is not really an answer to your question. I have not used a plasma before, but my class on Manufacturing Technology (and a few other related classes) say that the edges of item might become case hardened. Also, if the pattern has some acute corners there is stress build up and a possibility of fracturing if the item is not cooled down properly (slowly), or warping.

I thought, while you're on the subject of using "exotic" cutting methods, have you thought of water jet cutters? No heat.
 
Good points about stress etc with plasma
. I was recommended water cutting yesterday...sounds great but my budget won't stretch to $300K. Maybe I just got unlucky as to which place I rang but they reckoned that would be the cost of a machine and a small batch run of eg blade would be US$40 per blade. I think they were quietly telling me to get lost and stop bothering them. Bastids! Must persevere!
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I have used plasma in the past when I need lots of blade blanks. Use a white paint pen and trace your patturn. Advise whoever is doing the cutting to stay OUTSIDE the line. The heat radiation area is so narrow that the paint pen line will still be visible even if he cuts right up to the line. Also make sure that your cutter holds the tourch so that the cut is a right angles to the steel not beviled into you patturn.
No i'll effects noticed on 440C, ATS-34, or BG-42 because you still have to "clean up" the area of the cut to finish profiling the blade and this usually grinds away any "critically heated" areas of metal.

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Robert
Flat Land Knife Works
rdblad@telusplanet.net
http://members.tripod.com/knifeworks/index.html
 
Thanks for that Robert. I've managed (finally) to find a cheapish bandsaw only 1600 miles away. We've got a plasma cutter at work so your advice will still come in handy.
 
I tried cutting blades with a plasma cutter but I didn't like it. The cut edges are hardened and very ragged so you end up doing a lot of cleaning up. If you're starting with bar stock, I think it's easier to rough the blades out with a cutting wheel on a hand grinder, then grind to form. If you're starting from plate material then you do indeed have a problem. :-)

I'd really suggest looking further "down under" for someone with a water jet cutting system. As long as you have access to computer equipment where you can creat the DXF of the knife shape, it shouldn't cost too much to cut out the blades. Here in Germany it costs me about US$ 7 per blade for cutting and there are no stresses introduced into the steel at all. A water jet cutter allows you to order steel in plates (usually a better deal) and plan your cuts for max. material usage. It does make it tough to cut out one blade though - in order for it to be worthwhile to use the water jet system, I always have at least ten blades or more to have cut. Once I had over a 100 done at one time. (I'm still grinding on those as I need them.)

I'm also trying to round up a mateal cutting band saw though for design work and making prototypes. They bring a good bit of money here too.

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http://www.wilkins-knives.com
http://www.wilkins.de
 
Thanks Kevin...I do have .dxf and .dwg (etc)capabilty but still the one water jet place I spoke to said US$40 for a 4" blade
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I've found my bandsaw now, am happy
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Hi Ferret!
I think you made a wise choice in picking a bandsaw. Several years ago I used a penthograph with a plasma cutter attached to it. This was a way cool technique to cut blades and liners. I could have a liner cut in 3 seconds! The only problem was that the edges were really hard and the slag build-up was unbelievable. Also, the heat created stress within the material. But thinking back it was a pretty cool machine.
There is a plasma cutter that is called high-definition(I think), it is supposed to be in between a plasma cutter and a laser. But we are talking big $$$.
I hope this helps.
Allen Elishewitz
 
i have blanks cut by admiral steel. they use a laser. its great for my culinary knives, i order batchs of 50 plus on my rhino chop and one hundred plus on the steak knives. they have a $150.00 min, on the laser cut steel so you can get smaller runs. ask for terry summers

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Laurence Segal www.RHINOKNIVES.com
 
I just got back components for 55 of my SE D/A's (Liners-Bolsters-Backspacers-Pocket Clips) from Bailey Bradshaw. I will never go back to Laserjet or waterjet. I still have to shoot the holes in, but the locks are cut (.015 kerf btw) and the profiles are FINISHED
within .00002 of my cad drawing. I am in heaven and highly recommend it.
I'm going back in the morning for more!!
Oh yeah, he cut my leaf springs with the pin radius already in nad the arc in. Heated treated them and no more bending and grinding
ding dong springs to match. Consistency from knife to knife is mavless, simply mavless!!!
You should give him a call and let him make you a happy camper too! Larry D.
 
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