Tempering Jig

[PEU]

When I do HT I do it in large batches and tempering was always my bottleneck, the problem is that if I pile up all the blades they behave as a solid chunk of steel, and if I use the hardening frame, I harden 5 blades at a time, I have to do many batches.

So I had this idea, to make a jig that fits the entire chamber of my oven, the design puts all the blades with at least 2mm separation and at a progressively different height.

I also use this jig to thermal stress relieve AEB-L and Sandvik 14C28N otherwise they are bananas after HT...

Used stainless to make it and 3 connecting rods.

To be sure it works, also made a multiple K probe thermometer using arduino, which I connected to Thingspeak via WIFI to plot the temperature curves over time and check it reached an homogenous temperature over the width of the chamber.

It works, saves me a ton of time. I'm happy.

Pablo

 

[anvilring]

"I also use this jig to thermal stress relieve AEB-L and Sandvik 14C28N otherwise they are bananas after HT..."

What do you mean " bananas"?

 

[HSC ///]

"I also use this jig to thermal stress relieve AEB-L and Sandvik 14C28N otherwise they are bananas after HT..."

What do you mean " bananas"?

AEBL has a tendency to bend out of straight dramatically

stress relieving prior to hardening seems to help

 

[12345678910]

"I also use this jig to thermal stress relieve AEB-L and Sandvik 14C28N otherwise they are bananas after HT..."

What do you mean " bananas"?

They warp significantly after heat treat.

 

[PEU]

I meant curved like a banana
For kitchen knives I use mostly Sandvik 14C28N, an evolutionary copy of Uddeholm AEB-L AFAIK.
This steel is stored in rolls and sold in sheets. So, when you laser cut these sheets the individual pieces recall this roll memory and are all curved.
You may try to force them straight during HT by using clamping pressure during the air quench, but in my experience, the shield is half as good than if I thermal cycle them followed by clamping between aluminium sheets. Yes it takes a bit of work, but its far less than straightening after HT.

Pablo

 

[Hubert S.]

I meant curved like a banana
For kitchen knives I use mostly Sandvik 14C28N, an evolutionary copy of Uddeholm AEB-L AFAIK.
This steel is stored in rolls and sold in sheets. So, when you laser cut these sheets the individual pieces recall this roll memory and are all curved.
You may try to force them straight during HT by using clamping pressure during the air quench, but in my experience, the shield is half as good than if I thermal cycle them followed by clamping between aluminium sheets. Yes it takes a bit of work, but its far less than straightening after HT.

Pablo

Can you share your method for thermal cycling (temperature/time)? I want to do some more thin blades and they have come out more like wet noodles rather than bananas. If this is feasible with just a simple PID controller on the furnace I will give it a try.

 

[weo]

Used stainless to make it and 3 connecting rods.

I'd love to see it empty. Did you cut out the frames?

 

[PEU]

Here you go:

 

[weo]

I like it. Thanks for sharing

 

[JTknives]

We use something similar but we buy them not make them.