Jon Smith

Aluminum quench plates

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I was watching a new show on Discocery last night, "Blade Brothers", which is a series featuring a custom knife shop (stock removal=sad face). One of the things I found intriguing was the maker's method of quenching the steel by sandwiching the piece straight out of the HT oven between two 1" thick slabs of aluminum to use as a heat sink. Any craftsmen around here ever try that? Thoughts on this method vs say oil or water quenching (based on the steel in use)?

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I would think that good contact (especially at the edge) would be a problem!  Also it seems likely to be slower than ideal IMO.  I won't be switching over any time soon!

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Sadly Discovery Channel does not check facts, but repeats myths and in a few cases total screw ups,  I recall one where they talked about damansuc swords, and the smith was using 5160 mono steel. then entire the super steel thing,  its entertainment, but I wish they used real fact checking. 

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havent seen the show.

 

but alu quench plates works wonders on blades made from air hardening steels i know several knifemakers who use it but yes they are all stock removers

it also helps minimising warpage / twisting  

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havent seen the show.

 

but alu quench plates works wonders on blades made from air hardening steels i know several knifemakers who use it but yes they are all stock removers

it also helps minimising warpage / twisting  

 

 

Funny you would mention warping, cause he warped a big cleaver he was making for a customer.  It was salvagable but it was warped in two planes.  He claimed it was because it was from being in heat treat to long, his younger bumbling brother had taken too long to get back with the larger aluminium plates he needed.  Seems to me you wouldn't even start heat treating untill you had all your matterials in place.  But what do I know?  I'm not a pro knife maker on national TV.

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Discovey Channel isn't educational, it's entertainment. Seriously, the Mythbusters for all their BS faults do better science.

 

Al aught to work fine as chill plates, it might take some careful positioning to make good contact with the full blade I bought a couple Al half sheet pans, (big , thick, 1/8"+ Al cookie sheets) And they'' thaw a couple lbs. of frozen meat in about 1.5 hrs. or cool a pie in one. Put a frozen something on one and in about 30-45 seconds the whole sheet is COLD. Maybe 30 seconds after you set a hot pie on one and don't touch it. Al sheet pans work dandy as radiators in my kitches, aught to work in a knife shop.

 

Frosty the Lucky.

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I'll definitely be sticking with my liquid quench. The fact that he warps a piece, and badly, right there is a bad sign....


And the Mythbusters are never wrong. They busted that myth in season 9.

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More avouit wot was said above about contact. if you put a beveled blade between two pieces of parralel aluminum you will get contact only at the thickest part of the blade...which in a blade with bevels,,either forged ground or both, and think about a long distal tapered blade. Yoiu will quench the plart of the blade more at the top of the ricasso area, or if it does not have a tapered tang, the tang will also lharden...so yoiu will then have a blade with uneven hardening in  the two areas that I feel will help the knife in the least.

 

Now of course you could make those AL pieces to provide complete contact all over the blade...and if you made different shapes, profiles, of blades you could make different blocks for each new model..

 

And you would need to test each type of steel you use to see if this type of quenching makes it hard enouigh to skate a file before tempering...Unless youi have a rockwell tester to get the numbers and compare to the steel heat ttreat specs.

 

May even wish to consider info on this site for heat trat info rather than hollywood productions.

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Rich, if I remember correctly, the profile of the cleaver was milled and then the slab was "hardened" and then profiled and ground on a KMG/clone. That would solve the bevel issue--there was none at the time.

Also, I have no intention of trying this, if only because I can't afford massive slabs of aluminum on a college budget. I have read the HT stickies and all the knife chats, as well as doing my own shop tests. My blades are 5160 and quenched in warm oil.

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As long as a blade has a single even taper it's be easy enough to place the chill plates at the same angle to provide even chilling. A double edged blade would be a different story of course. I suppose a matching channel could be ground/milled in the al chill plates but. . .

 

Frosty the Lucky.

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