Quenching 3/8" thick 3v

Willie71

Willie71

Warren J. Krywko
Joined
Feb 23, 2013
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I'm doing a chopper for a fellow who wants a totally overbuilt knife. It's 3/8" 3v, 2" tall with a Scandi grind. Not the geometry I recommended, but this is what he wants, and is very clear on that. I haven't quenched steel this thick before, and am asking for those who work with thicker steel if 1" thick aluminum plates will quench quick enough, or should I use a medium oil? I have both options.

Warren
 
Scandi grind blade 3/8" thick 2" wide at 1900+F has large & thick thermal mass. Quench oil will burns for a good ~10-15 seconds in smoke jacket. High likely aluminum plate surface will suffer some shallow burn/scorch spots.

I would plate quench with mild steel bars ~1/2"x4"x 20" (TxWxL) for up to 20 seconds, then transfer to aluminum plate quench for ~2-3 minutes or oil quench if you want. If still too hot, wet paper toweling until cool to hold; water cool; wipe and then do rest of your ht.
 
Willie71 said:
I'm doing a chopper for a fellow who wants a totally overbuilt knife. It's 3/8" 3v, 2" tall with a Scandi grind. Not the geometry I recommended, but this is what he wants, and is very clear on that. I haven't quenched steel this thick before, and am asking for those who work with thicker steel if 1" thick aluminum plates will quench quick enough, or should I use a medium oil? I have both options.

Warren
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😳I know the customer is always right, but this might be pushing it! Lol. Sorry, nothing constructive to add here.
 
jsut did a 5/8 thick bar of 10v little over an inch wide and 13 inch long my Al plates are 1x6x18 did that one blade jsut fine but sure would not do more then one withought cooling the plates off in a bucket of cold water
less then a min in the plates and it wasa under the nose so it quenched with plenty of time left
 
Thanks everyone for the comments. I thought about passing on the job, but being part time and not depending on knifemaking for income allows me to make odd projects. The job intrigued me. I know 1/4" will quench fine in my plates, but I do have 20 gallons of medium oil to work with as well.

I'll try with the plates, and if it doesn't work, I'll redo it in the oil.

I'll post some pics when I get to the project, which will be in at least 2 weeks.
 
Is this going to be a true scandi? Or a saber grind.

I can't imagine the ineffeciency of a short scandi on a blade like that.
 
Just remember that steels at those temps. (air hardening temps.) are extremely hard on quench oils and will reduce their life pretty quickly. Especially ones with that much mass.
 
what about misting your aluminum plates with water during the plate quench? This should help get the temp down pretty quick. Not sure about 3V, but Sandvik steels only require getting below 1100ºF in less than 2 minutes....
 
I place my quench plates in ice chest with dry ice to get them cold before quench.
 
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Ken H> said:
what about misting your aluminum plates with water during the plate quench? This should help get the temp down pretty quick. Not sure about 3V, but Sandvik steels only require getting below 1100ºF in less than 2 minutes....
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I'd have to look it up again for the exact specs, but it's under about 1000 in one minute for 3v.
 
Bigfattyt said:
Is this going to be a true scandi? Or a saber grind.

I can't imagine the ineffeciency of a short scandi on a blade like that.
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Tru Scandi, not a sabre grind. Client wants more of a show piece than a real cutting tool. We discussed this at length. I suggested using 80crv2 instead, to save money, but he wants 3V, and paid for the steel in advance. He says he knows the blade is "ridiculous." If he was expecting performance, I wouldn't do it, as I know it won't cut, as FIF says. Client is honest about what he wants, and expects, so I agreed. 👍.
 
Spray not mist ! But I think Butch's way is better. Some go to the trouble of drilling holes through the Al attaching tubing and have a continuous flow through the AL,but that's only for doing many.
 
Ja Baudin said:
I place my quench plates in ice chest with dry ice to get them cold before quench.
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This raises a question for me. We use warmed oil so it quenches more efficiently. Would cooling the plates make them quench less efficiently?
 
butcher_block said:
jsut did a 5/8 thick bar of 10v little over an inch wide and 13 inch long my Al plates are 1x6x18 did that one blade jsut fine but sure would not do more then one withought cooling the plates off in a bucket of cold water
less then a min in the plates and it wasa under the nose so it quenched with plenty of time left
Click to expand...

Thank you Butch. The fact that you have quenched a similar project is exactly what I needed. Much appreciated.
 
Willie71 said:
This raises a question for me. We use warmed oil so it quenches more efficiently. Would cooling the plates make them quench less efficiently?
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Oil gets thinner when warm, aluminum, well I guess it does too! But it needs to get to 1000 degrees or so before that happens!
 
Willie71 said:
Thank you Butch. The fact that you have quenched a similar project is exactly what I needed. Much appreciated.
Click to expand...

The heat transfer of oil are depending on viscosity. Heating oil to some degree will reduce it viscosity and improve the quench cooling rate.

The is the opposite story to freezing aluminium plate since the -20F plate will have much high cooling rate than the room temperature one.
 
rate of cooling i dont think changes but having the plates that cold give more "space" for the heat to transfer
 
Freezing quench plates is a waste of time and money. These are air hardening steels. Therefore, they will harden in still air. Knifemakers use plates to slightly speed up the process and keep warpage to a minimum.
 
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