Tempering equipment question

BobbyD

Well-Known Member
It has been suggested to use a metal rack to hold the blades upright spine down In a toaster oven to help avoid warping. What are you guys using?
Of all the videos I have watched the blades are just put in on there sides. Not saying that is right or wrong just trying take all precautions that I can.
 

Kevin R. Cashen

Super Moderator
Never place blades flat, on their sides, on any surface, during a heat treatment operation. Unless you are shooting for warped blades. The less material you have touching that blade during tempering, the better. When I have taught classes that had small ovens that required blades to overlap and touch each other, they invariably warped. I highly recommend the wire rack that holds the blades, edge up, in the air, during tempering. The wire has the least contact with the blades, and is a conducting material that will heat along with the blades, providing the most even heating possible.
 

BobbyD

Well-Known Member
Kevin I have a rack that seems like it would work good with the spine up. Would that be ok?
 

Smallshop

KNIFE MAKER
Hey...has anyone used a toaster oven with convection ability? I wonder if the convection keeps the temp even? I bought a kitchen aid with that ability bout a year ago but have been using an old full size residential electric oven that is working well. Don't want to test if other guys have input that it does not offer advantages.
 

bladegrinder

Well-Known Member
Ted, I bought a convection toaster oven a month or so ago. I've only used it a few times to temper blades but always used it in convection mode. I've found that after letting it run for 20 min. or so it holds temp. pretty tight.
the thing I have found though and didn't surprise me was the dial and true temp. were way off. I use a hand held thermometer with a thermocouple that I sneak thru the door and hang it in there, it works good.
 

opaul

Well-Known Member
I must be lucky. All of the blades I have tempered in the kitchen oven have been placed on aluminum foil flat and I haven’t had one to warp out of tempering.
But I will heed to the more experienced and begin placing them on the edge.
 

Andre Grobler

Well-Known Member
I welded two thin gauge angle iron pieces parallel to each other about 5" apart and cut narrow v-slots in them with a thin angle grinder blade. the blade spans both and is supported only by points on the slots. the rack stays in and i use gloves to place blades in the heated oven... tc also connected to the angle iron, it approximates the cross section of most of my blades, so measurement should be close...
 
Ted, I bought a convection toaster oven a month or so ago. I've only used it a few times to temper blades but always used it in convection mode. I've found that after letting it run for 20 min. or so it holds temp. pretty tight.
the thing I have found though and didn't surprise me was the dial and true temp. were way off. I use a hand held thermometer with a thermocouple that I sneak thru the door and hang it in there, it works good.
I have been rUnning a convection toaster oven as well and let it warm up and it stays steady as well
 

Smallshop

KNIFE MAKER
Ted, I bought a convection toaster oven a month or so ago. I've only used it a few times to temper blades but always used it in convection mode. I've found that after letting it run for 20 min. or so it holds temp. pretty tight.
the thing I have found though and didn't surprise me was the dial and true temp. were way off. I use a hand held thermometer with a thermocouple that I sneak thru the door and hang it in there, it works good.
Thanks Mike...and guys! (somehow I missed the rest of this thread...)

The footprint of a small convection/toaster oven is ideal....
 

Daniel Macina

Well-Known Member
I use a convection oven (16” long I think.) I got lucky on it because it holds a +/- of 10° Without any modification. I just slide an old drillbit through a pinhole to hold it on its spine in the oven.
 

billyO

Well-Known Member
One thing I do to help keep the temps steady is to put my blade holder on a large cast iron pan (upside down) to add some thermal mass to the oven to help keep a steadier temp. I used to load up the oven with large chinks of mild steel, but that was overkill and probably contributed to my burning up and having to replace the heating element after a couple of years of use.
 

tkroenlein

Well-Known Member
Yeah I was just scrolling past this and remembered what I wanted to say the other day. Not only have I had the best success tempering spine down, I've also had the best success hanging my blades after I took them out to cool.
 
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