Recommendation? Pre or Post Heat Grind

S

Stump1800

Joined
Jul 21, 2014
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18
I've always ground bevel prior to heat treat... problem is always had hard time cleaning scale from grind area, especially plunge...Should I heat treat first, then grind?

Stump1800

kwl@breck.com
 
Well, you could absolutely fully grind after heat treat. But I don't think the reason should be because it's hard to clean scale from the grind area. You should be able to get rid of scales with belts and/or hand sanding.

And as usual, there are pros and cons with both alternatives. I think they complement each other when used in different scenarios. I pre-HT grind all blades except thin kitchen knives. It saves on belts and time.
 
scotchbrite belts are pretty good at getting that last bit of scale out of the plunge.
 
Best thing to do is give the blade a soak in a sulfuric acid solution to dissolve the decarb. Then you can easily finish the bevel with a scotchbrite belt. They fit very will into the plunges and are great for cleaning things up.

For what its worth, I actually hard grind most of my blades. Its not that bad and it allows me to work on blades in small numbers instead of having to bulk grind 20 at a time before sending them off to HT.
 
If you're not grinding the scale away you're not grinding the decarb away. If it's hard to get into the plunge, don't grind it so deep before HT. Leave them shallow and finish them after HT.

Not grinding anything prior to HT just because of the plunges is throwing the baby out with the bath water.
 
In my experience you will burn through a lot more belts grinding after heat treat than you will just cleaning up plunges post heat treat. You also run the risk of ruining your heat treat, which in my book is a lot easier then you might think.

If you're using carbon steel and don't like decarb and scale get some atp 641 from brownell's and coat your blade with that. My stuff usually comes out looking like knives I use foil on, very clean.

-Clint
 
currenthill said:
Well, you could absolutely fully grind after heat treat. But I don't think the reason should be because it's hard to clean scale from the grind area. You should be able to get rid of scales with belts and/or hand sanding.

And as usual, there are pros and cons with both alternatives. I think they complement each other when used in different scenarios. I pre-HT grind all blades except thin kitchen knives. It saves on belts and time.
Click to expand...

Thanks current..., that's what I do...just thought i'd ask.

stump1800
 
I went to post heat treat several years ago when I made a few kitchen knives.It works well now for the folder blades I do.
Frank
 
I'm post heat treat on about 90% of my knives. I'm grinding a lot of 3V lately and have been pre grinding a bit so save on belts and time as it is so wear resistant.
 
Stainless under 1/8, I grind hard. Thick stainless, I grind pre HT and then clean up. Carbon, I grind pre-HT and then clean up, every thickness.
 
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