Manufacteuring processes

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jjcoolay

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What are the general steps that a knife goes through in order for it to be made into a knife?

What I mean by this is the order that the steps come in. In no particluar order, heat treat, temper(same as heat treat??,grinding, lasering out/stamping, quenching etc etc..
 
There are two major processes: Forging and stock removal. There are many variations of both and the processes used by custom makers necessarily vary from those used by manufacturers. And, of course, the processed for a folding knife are usually much more elaborate than those for a fixed-blade.

At a typical manufacturer, "soft steel," steel which has not been hardened, arrives in flat sheets of a specific thickness. It is then cut into "blade blanks" by either stamping, laser, or EDM.

Here is a very interesting if mis-labeled eBay auction. The seller thinks it's a blade mold. It's not. It's just a scrap piece of sheet steel that was left over after blade blankes were stamped out of it.

The blanks are then "profiled" by a machining process.

The profiled blade is heat-treated in a furnace. This hardens the steel.

The heat-treatment process can cause minor dimensional changes in the blank. So, precision machining processes, e.g. drilling holes for the folding mechanisms of a folding knife, are done after the blade blank is hardened.

A rough finish goes on.

The blade is then assembled into a knife and then sharpened and maybe polished.

Of course, there are many variations on this. And I'll let someone else discourse on forging.
 
You may wish to read This Essay by Professor Roland Phlip of the Institute for Advanced Balisong Studies. He discusses blade hardening and Rockwell testing and gives some interesting links to other sites.
 
Originally posted by jjcoolay
What are the general steps that a knife goes through in order for it to be made into a knife?

What I mean by this is the order that the steps come in. In no particluar order, heat treat, temper(same as heat treat??,grinding, lasering out/stamping, quenching etc etc..
Click to expand...


There was a show on TLC or Discovery calles How is that made? I think it went 7 episodes. It wasn't that great of a show because they explained everything like the audience were made up of second graders.

They did on one show go to a Chicago Cutlery plant where they made their premium line of kitchen cutlery.

They went step by step through the plant fromm when the steel came in the door to the finnished knife.

Chicago Cutlery used Coil steel for their knives and blanked them oversized on a stamping press. Then they were straightened and clamped into a jig on a cnc mill that profiled the blades like 40 at a time to remove the burrs and breakage from the stamping. Then they were clamped into bundles about an inch thick and heat treated after heat treat the blades were hollow ground on an automated wet grinder. The flats were cleaned up to a brushed finish and the handles and bolsters were applied and shaped. The finish was applied to the handles and they are buffed and sharpened.
Drew
 
In general with most steels the following is the simple sequence to make a blade. As mentioned the steel comes "soft". If it is not then it is easier to grind if it is "annealed". To anneal it you heat it up to a temperature where a magnet will no longet stick to it then immediatly put it in a big barrell with like vermiculite to allow it to slowly cool over night.

Once the blade has been shaped you harden it by again heating it up to non-magnetic, this time though you submerse the blade in 350 degree oil. If you want to differencially harden it you start with quenching the edge of the blade first.

Then most makers temper the blade by twice heating up the blade to 350 degrees in an ordinary oven and allowing to cool in between.
 
Nobody had jumped in to describe forging?

Come on folks. This poor guy is gonna go away thinking all knives are stock-removal.
 
Both of those sites are exactly what I was looking for. Thanks for the effort.
Thanks to everyone who has replied to my inquires. But special thanks to Gollnick for going the extra mile.
 
"The heat-treatment process can cause minor dimensional changes in the blank. So, precision machining processes, e.g. drilling holes for the folding mechanisms of a folding knife, are done after the blade blank is hardened . . ." Chuck Gollnick

Mr Gollnick also recommended that you look at the following:

"A typical heat-treatment process is to heat the metal to 1600F, cool it very quickly, heat it back to 1400F, cool it very quickly again, heat it to 600F, and then allow it to cool slowly. Believe it or not, this simple process of heating, cooling, heating, cooling, heating, and cooling again will dramatically increase the hardness of the steel.

The heating can be done by putting the metal into a hot fire, a forge for example. You can judge the temperature by the color of the metal. The cooling can be done by plunging the material into cold water. But these methods, while still used by many knife makers, are poorly controlled and produce inconsistent results. . . . . . . . " Professor Roland Phlip

I do not know Professor Phlip, he may be an expert in some field but I do not think it has to do with the heat treating of tool steels. Mr. Gollnick is of course an expert in the knife field, he is not only a moderator he has posted more than 8,000 times on this forum. I hope that his other posts are more helpful than the above. Anyone drilling steel hardened to 60 Rc is going to spend a lot of money on drill bits. 50 years ago when I tried to harden tool steel by plunging red hot knife blades into cold water the shock to the blade was such that it shattered and I removed it from the water in pieces.

MisInformation of this kind is a blight on the Internet, people ask for help and those who jump in often have not a clue about what they say and they those who could help fear being flamed and so the real information never gets into place. I have already been flamed and find that I can live with it. I seldom post but I could not allow this to pass.

If you want heat treating information you can get it at the web site of a steel company for the steel you wish to use. Try the web sites of knifemakers like Bob Dozier and read the knifemaking books like "How to Make Knives" by Richard Barney and R. W. Loveless or "The Master Bladesmith" by Jim Hrisoulas.

"With malice toward none. . . A. G.
 
Professor Phlip's short essay on a complicated subject, a subject on which many books have been written and you can literally earn a doctoral degree in if you like, was not intended as detailed instructions. He was mearly trying to convey the general idea and to do so in a way that is short and fun to read. You'll notice that he supplies several links to other resources that are more exact and detailed.

Professor Phlip concludes his essay saying, "There are, of course, many other aspects of heat-treatment and blade hardness. But this should give you some background to start with."


Drilling and machining hardened metal is a non-preferred manufacturing process, that's certainly true. It's slow. It requires expensive tools. And it's hard on those tools. But it's not impossible. And when the shape has to be exact or the hole has to be in exactly the right place, as is the case with some modern locking mechanisms, it sometimes has to be done.
 
Last night I happened to catch a blurb on the guys who make the Swiss Army knife. Seems they manufacture 150,000 knives a day. Didn't think the Swiss Army was that big.
 
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