3V Warpage?? Paul or Jerry??

T

tom mayo

Joined
Jan 27, 1999
Messages
6,277
Well...Jerry has me about talked into making some knives out of 3v.....how bad is the warpage on regular type grinds from "normal" people? will hollow grinds on .125" and .156" folder blades warp significantly?? If its hard to grind annealled i certainly dont want to have to grind any warpage out of a hardened 4" folder blade....thanks in advance....and Jerry...how thin can you grind this stuff without worries.....I mean I dont really want to cut any bricks in half here....just a few axis deer...
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http://www.mayoknives.com


 
Tom I dont know if I am "normal" but I have ground quite a few blades from 3v. I dont do hollow grinds but the very thin flat grinds (.008" at the edge) never come back from Paul Bos warped. By the way I was his first 3v guy. I like to grind 3v but its a little hard on band saw blades. After heat-treat it is very hard to remove scratches so do all the grinding first. Bruce
 
Tom, my blades all warp badly, but that's just my blades. It's due to my extreme grinds, and probably because I don't do it evenly enough. I don't think it warps any worse than ATS-34, but it's real difficult to straighten. Paul says that even at 500 degrees right out of the hardening oven it is like a spring. That said, Paul has straightened them all, though I think he was talking between clenched teeth when we spoke on the phone last.

I have not found the lower limit on how thin 3V can be ground. Darrel might have an answer here. I have had no trouble with anything breaking, and that includes some nail chopping. I haven't tried concrete like you recommend
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, but it's tough enough for sure.

MrG did in fact cut some slivers off a steel bar (by accident and not recommended!!!) without damage, and his edge was about the finest I've done. Again, my edges are not all that fine though. That knife had a Moran edge that began at about 0.025" with a longish convex bevel ending up at about 22-25 degrees. Guess.

We've talked. You know I like this stuff. I take my initial grinds down to a well worn 220 grit belt before heat treating. (You'll have lots of well worn belts after working with 3V.) I do some edge smoothing and preliminary bevel shaping before heat treating as well. After heat treating, I start with 120 grit, then worn 220 again, then 400 grit, then Trizact 16's. At that point it is almost polished ( as close as it gets anyway). I then use a loose buff at 1750 with 400 grit greaseless compound (Matchless from Koval) to give it a brushed finish running the length of the blade. I then hit it with Scratchless Pink on a loose buff (CAUTION) at 3600. This gives it a bit more shine and removes some of the brushed finish. I then go over it again with the 400 grit greasless, but very light this time, just to even it out. That's it. I've tried improving on this with 600 grit paper by hand, but it doesn't seem to do a thing.

Generally speaking it takes me twice as long as ATS-34 and uses twice as many expensive belts.

Good luck, dude.

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Jerry Hossom
www.hossom.com
The Tom & Jerry Show
 
Tom yes it is a problem. After talking to Crucible about the warpage issues on 440v, 3v ,420 v I am using quench plates. This is an old trick in the heat treating industry. Others use this I believe also.
I use 2 -3/4 thick aluminum quench plates.
When the blade comes from the oven I place it between the plates and clamp it. This keeps it straight and moves the heat from the blade fast enough to obtain the hardness. The ttt curve on 3 v is fast so this will get then temp down fast enough to obtain full hardness. 420 and 440 in my experence harden
with easy. 3v is differnt. Also then can be marquenched if you salt baths that will go to the high temp requirement. I have had a few blades do this way also.

If you grind first I recommend leaving a flat
out to the edge and tip to keep the blade straight.
Then just semi rough grind and finish after heat treat.
I also have a temper set up for the blades.
I use two 1.5 thick bars of flat steel .
I clamp the blade or blades in the temper jig between the two plates, then temper the blades. This takes warp out also.
Generaly I can maintain about .005 flatness
This does not hold true for every one. Once in a while you get a bastid.

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Web Site At www.darrelralph.com

[This message has been edited by Darrel Ralph (edited 07-02-2000).]
 

Darrel:

I'm planing to put in a quench plate clamping vice of some sort...

With our asymetrical grinds and the 1084, we see about 5% loss due to warpage...

How does this work on simple carbon steels like 5160 or 1084...

Will you get a good quench on these steels?

Thanks for your input...

Running Dog

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Running Dog Knife Company
mmurphy@premier1.net

www.runningdogknife.bigstep.com
 
uuugggghhhhh......this is not good.....from what jerry says i was planning on finishing the 3v before heat treat!!!
 
Since when have you ever listened to me? Darrel has vastly more experience than I do with blades coming out of the oven. I stopped doing my own heat treating a couple years ago, so all I know is how many tranquilizers it takes to make Paul happy again.

There is no question though that the fewer stresses you put in the steel before heat treating, the less it is going to warp. The problem my blades would have with the quenching plates (good idea though) is the tapered tangs. They aren't going to touch the plates, and they are an area of the blade where warping is a problem for me.

I suggest you do your best, and send Paul something nice for his trouble, like maybe a cherry condition 32 Ford chassis...
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Jerry Hossom
www.hossom.com
The Tom & Jerry Show
 
Low on funds right now....spent all my money on stuff to make tnts....how about you send me three or four of your folders unassembled and i can look at them and put them together and send them back....
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http://www.mayoknives.com


 
Hello,

the warpage problem may be also how the bar stock is cut from the sheet, if its not cut with the rolled grain of the sheet and is cut cross grain off the end of a sheet it will cause warpage problems. Found this out the hard way by having some blade lazer cut out of ATS-34 that way to get the most blades out of a sheet, got more blades that way but they all warped because they wee cut against the grain.

my .02

allen

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Allen Blade
Spokane,WA USA

" You can make great knives and sell a few, Or make Great AFFORDABLE knives and sell many"
WEB SITE : http://hometown.aol.com/bladecutlery/index.html
 
But, but but... given that the knife is thicker at the spine than the edge, don't the quench plates only contact the spine, and cause it to cool faster than the edge?

What am I missing here?
 
Allen, was this hot rolled or cold rolled, and was it annealed first? Do you think annealing before would make a difference?

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Oz

"I'm politically opposed to the word 'Impossible'."
http://www.freespeech.org/oz/
 
Tom , Jerry , Daryal is right on with the Quench Plates, But when you have tapered tanges, and tapered blades, you cant use plates. Do your grindes evenley and try to keep as cool as posible. Tom just do your normal grindes an I will try to keep it as straight as posible. Paul. P.S. Sorry im so late ansuring this , I have been out of town to see our new Grand Daughter.
 
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