plate quenching multiple blades?

Cousin Jack

Cousin Jack

Joined
Oct 25, 2002
Messages
709
If I am HT'ing multiple blades at the same time (same thickness), how do I go about plate quenching them? Do I take the time to lay them all down side by side on the bottom plate then cover with the top plate? Do one at a time? or....

thanks in advance guys!
 
i do both
if there the same thickness i grab 2 at a time and go that way i just make sure that they are not over lapping and that the whole blade is on the plate
 
You can put them in one envelope side by side [don't stack them] and plate quench them together.
 
I have a set of plates that are 4" wide by 16 " long. I usually heat treat 5 or 6 blades at a time. I try to quench 2 blades at a time if I have room. Otherwise you have to do them one at a time. It is somewhat of a juggling act. That's how I do it.
-John
 
thanks guys...

Is there a certain window of opportunity/time that an air quenched steel needs to be plate quenched, or is it okay for it to sit a bit while "waiting its turn" to be drawn?
 
May be a few secs. Plates help to straighten blades if they come out bent, but for it
to work, the blade must be "soft" , at least red hot.

And of course, plates quench much, much faster that still air - but how much benefit
there is to such fast quench, remains to be seen :)
 
I don't like them to sit. I try to do it when they are red hot.
-John
 
You are attempting to short cut the single most important step in knife making, the HT. This is where great attention should not be compromised. Just my opinion but I highly recommend HT'ing only one blade at a time and giving each your full attention. Regardless of how you place multiple blades in the furnace chamber temperatures will not match. It is difficult enough to do one blade at a time properly let alone multiples. There is also timing to quench and etc.. Without an automated industrial system I advise taking the extra time, effort and expenditure to HT only one blade at a time (at least up to and including primary temper).

rlinger
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rlinger said:
You are attempting to short cut the single most important step in knife making, the HT. This is where great attention should not be compromised. Just my opinion but I highly recommend HT'ing only one blade at a time and giving each your full attention. Regardless of how you place multiple blades in the furnace chamber temperatures will not match. It is difficult enough to do one blade at a time properly let alone multiples. There is also timing to quench and etc.. Without an automated industrial system I advise taking the extra time, effort and expenditure to HT only one blade at a time (at least up to and including primary temper).

rlinger
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Click to expand...

No, that is not my intention.

With multiple blades, I would have to believe that an adjustment in soak time will pretty much equalize the internal temperature of the HT oven. If this was a large oven, then I would be concerned about uneven heating, but it is not. it's a small oven. Also, the blades being treated are of the air quenching grade, so the time to quench really isn't a factor IMHO.
 
HTing one blade at a time isn't really practical for most. It takes a lot of time to HT. I think for air hardened steel small batches of 5 blades or so is fine.
-John
 
one at a time i could not get away with the preheat at 1500 and then the soak of 30 min at 2000f 6-8 blades would indeed run me most of the day

thats alot of unneeded killn running there
 
Cousin jack-You should leave them all in the foil packet, and transfer the whole packet onto your quench plate, then, cover with the second plate.

Multiple blades, all of exactly the same thickness, can easily and efficiently (and precisely!) be quenched in this manner. You need big, thick plates to handle the heat-1" thick minimum-thicker is better, and the plates must be larger than your packet.

Mutiple blades in the packet permits each blade to receive exactly the same cycle, and to be quenched on plates that are the same temperature. think about it.
 
Cousin Jack,
I got my plate off *bay pretty cheap. They got some really thick ones on there.
I leave mine in the foil too.
-John
 
Okay fellows. What ever you think best. Maybe you can start drilling tang holes five blades stacked. As for deep hardening steel: take it for granted if you wish. Short cuts usually show up as such. I choose to spend the extra effort and cost. That is how I did it when HT'ing for other makers and that is how I do it for my knife customers, one blade at a time. The single most important part of blade making is the heat treat. Shallow, medium or deep hardening steels - no difference in attention, timing and all other detail. Kiln, furnace running time is not the issue. It should not be a consideration because in doing so we compromise or promote compromise. As for oven or furnace size: I really tried to understand that comment but can not. Were you trying to say that because the chamber is small enough it does not cause adjacent steels to be different in temperature? Stacked, spaced, bunched up together, they will be dissimilar. Industrial heat treating facilities are made for mass production. Ours are not. That is part of what makes us special to the customer that depends on us.

rlinger
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rj martin said:
.....Mutiple blades in the packet permits each blade to receive exactly the same cycle, and to be quenched on plates that are the same temperature. think about it.
Click to expand...

RJ- Are you saying that I can put more than one blade in a SS foil packet? Stacked side by side?
 
rlinger,
Respectfully, I disagree that you have to heat treat one blade at a time. You obviously have more experience than I do, but I don't believe that you have to treat one blade at a time.

In an oven that is less than 1 cubic ft., the temperature will be about as uniform as any temperature can be within any space. If you have a 100 degree temperature range to heat treat within, meaning the data sheet on a certain type of stainless steel says heat treat between 1900 and 2000 F for 30 minutes to 1 hour depending upon thickness. You program your oven to heat treat them at 1950F for 40 min. You may have 4 5/32" blades of the same steel; one blade is at say 1953 F, and the one next to it is 1948 F, and the next one is 1945 F and the next one is 1956 F. AND, you keep it with this range for 40 min. Then I would find it very unlikely that there would be any measurable differences between the hardness of those blades by the current measuring devices used. I definitely do not think its possible for your oven to be set at 1950 and one blade be 1900 F and one be 2000. No way.

I also understand that we all have our own notions of how precise things need to be and how precise they can be, and how precise we think they need to be.

If it works for you then keep doing it. There are more than one way to do things. We all have our own methods and styles and that's why we are custom knife makers. I don't think your way is wrong and I don't think my way is wrong, they are just different.
-John
 
Cousin Jack: Yes, you can. Blades must be of the same steel type and of the exact same thickness. Make a larger envelope and nest your blades in a single layer.
Soak time is based on thickness, so you could nest both large and small blades together, but, I prefer to HT multiple blades that are identical or nearly identical at one time.

The interior of my furnace is 13 W x 21" deep. I specifically chose a model that has elements on both sides-they do not wrap around the back wall of the furnace, so there is no temperature gradient from front to back. Also, by resting my foil packet on top of a row of fire bricks running down the center of the furnace, my blades are at the same level as the thermocouple.

I have HT'd several thousand blades over the past 15 years-And I've had the results verified on numerous occasions, and by hundreds of customers using my blades. This method works. Try it.
 
Barker, I agree that we go our own ways as per this particular subject. Good luck with your multiple blade 40 minute soaks at ~ 1950 F.. Your guess is correct; I do like consistency.

rlinger
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I use mostly ats & d2 &oil quench & use liquid n2 can cpm be done the same way different temps of course I have never used quench plates sounds like they would be great for filleting knives big time worpping
 
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