dumb noob wants to profile with a mill...

D

DocWorkingday

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Oct 23, 2006
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Hi folks, I'm in, ahem, the early planning stages of making my first knife. I have access to a nice Bridgeport mill, and I'm planning to use it to cut the shape of my blade (& full tang) out of a piece of flat stock.

So far so good, right?

After that, can I use the mill to profile the blade? Maybe tilt the table 10 degrees off horizontal (edge up, spine down) and drag an end-mill along the edge? It seems like it'd work great for a straight edge (wharncliffe etc), but it'll be imperfect for anything with a belly.

Another idea is to keep the table flat and mill "terraces" into the edge, to do most of the stock removal, to make the sharpening quicker afterwards. Obviously the inside corner of each "stair-step" would be at or just above the final surface of the blade, and the outside corners of the steps would be filed away or sanded away on a belt sander.

Or should I stick to crossword puzzles? :o
 
Some of what you're describing is done routinely with so called "integral" knifes. These are milled from a solid bar of steel.

Now, when one has a decent belt grinder, bevels are typically ground on such
belt grinder, as opposed to being milled. But you might be onto something here !
 
This is how I do it. Degrees may vary with size of blade.

tt1.jpg
 
As much as I love my Bridgeport and milling machines in general, that seems like using a mill for all the wrong stuff to me. Milling reliefs, bolsters, cutting locks on a folder, all good uses for a mill. Profiling a blade would be quite a challenve if you want any curves, unless you are really good with a manual mill.
 
At least hack the rough profile out with a saw and then use the mill to finish the profile. A lot easier on expensive end mills.

rlinger
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J. MacDonald said:
As much as I love my Bridgeport and milling machines in general, that seems like using a mill for all the wrong stuff to me. Milling reliefs, bolsters, cutting locks on a folder, all good uses for a mill. Profiling a blade would be quite a challenve if you want any curves, unless you are really good with a manual mill.
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I'd have to agree, though it's interesting that someone is actually milling knife bevels. Obviously, the traditional method is grinding (belt grinders for custom/small-run makers, specialized CNC blade grinders for production.

I believe it's Angus Trim that pioneered the CNC machining of excellent quality medieval swords. If I understood his process which is now used by other makers (it's been a couple years now), he mills the entire blade in a piece of bar stock (1075 and 5160 are favorites), first one side ... bevels, fuller, etc. then flips the bar over and does the other side. The blade is later freed (cut) from the rest of the bar after the machining is complete. This is particularly handy because these swords get pretty thin in sections, have distal taper that can vary in rate along the blades length, and other nuances consistent with originals. If the sword remains in the bar until the very end, you eliminate a lot of fixturing/handling complication and can produce a repeatably accurate piece almost entirely on one machine with minimal handling.

You could probably work out a similar approach for knives if you have a machining center and some spare machine time. I suspect it would not be cost effective for knives compared with the traditional methods.
 
Thanks Brett, Don Robinson's stuff looks really interesting. The CNC technique holds a lot of appeal for me because I'm kind of clumsy... :)

Has anyone read Robinson's book? Or any other CNC knife-making books?
 
I have Don's "My Way" book and it's very well written and illustrated. I'm sure this one is as well.
-Ben M.
 
miden said:
This just opens up the old "can you really say it is hand made" debate again?;)

Mike
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CNC mill i think it is getting a little closer to a kit blade but a manual mill i think hell yeah its hand made. no different to someone who uses files saying that a knife grinder isnt hand made, its just different strokes for different folks.

i wont go on any longer wouldn't want to steal the thread
brett
 
holmsy said:
CNC mill i think it is getting a little closer to a kit blade but a manual mill i think hell yeah its hand made. no different to someone who uses files saying that a knife grinder isnt hand made ...
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I like the analogy of a guy with files thinking the guy with the grinder isn't making hand-made knives.
Still, I think the difference between using a manual mill vs CNC isn't all that vast either, at least not to the guy without a mill or CNC.

To me, a kit knife is something you didn't design.
 
Check the hardness of the material you are using befor you try cutting it with an end mill. Some of the material I have recieved tested up near 40RC which is near impossible to cut with a mill. A simple anneal will of course take care of this problem. Good luck
 
40 rc cuts ok with hi speed bit and cobalt works great, I have finaly gone to nothing butt carbide for steels, I run it about 600 Rpm dry, so I can see my work better, dont rush it & bits last forever, watch ebay, I cant believe how much money I have saved on tooling there. Carbides will cutt just about any steel no matter how hard. Also watch for carbide dagger drills they are fantastic, even on a hardened blade. I found it be much faster to rough out my blades with a mill. It is great for cutting the tapers.

Leon Pugh
 
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