how much to finish before heat treat?

Z

z537z

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Apr 14, 2004
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I've got a motor, belt grinding setup, belts, steel all either here or on the way.

Before I get started, how finished a product am I looking for before I heat treat the blade? Like, rough-ground, fine-ground, rough hand-sanded, or everything but final sharpening on a stone?

Thanks! Can't wait to get started.

_z
 
I like to take my blades to a 220 Grit finish before Heat Treating. You can do as much grinding as you want after HT, you just have to be carefull not to get too hot.

When my blades are ready to be heat treated they are pretty much to shape. Just need to be cleaned up. I try not to get my cutting edge or tip too thin prior to HT as most will tell you.

Good Luck and Have fun.

Shane
 
Like SKIVE said, but I'd say that with stainless I take it a good bit higher than with carbon. Specialy S30V, I found out the hard way that it's easier to work down high spots while it's still soft.
 
It depends whether you intend to do a lot of further grinding after the HT.

On my carbon steel blades, I do at least 25% of the grinding after the HT, so my pre-HT finish is just a 120grit finish straight off the grinder. Carbon steel HT-ed in my forge, with clay etc. ends with a lot of gunk and decarburised bits on the blade, so its a necessity. Some experienced makers will tell you about special methods they use to preserve the surface of the steel during the HT, so they take the finish much higher.

ON stainless and high-alloy blades, I have mine HT-ed by a professional outfit that uses vacuum, inert-gas (nitrogen) quench chambers, so there is no surface decarburisation and scale. I suspect most professional HT-ers do it this way too. With those blades, I finish my blades all the way up to the final finish desired. eg.- 1200grit / 1500grit satin hand rubbed. The only refinishing required after is to redo the last , eg.- 1200grit step of hand finishing. Or maybe to remove a couple of scratches that occured while they were doing the HT for me. Most stainless and high-alloy steels are horribly wear-resistant and will make you quite miserable trying to hand sand them after HT ! :D

Best of luck. Jason.
 
I try to have my knife almost done before HT (short blades, simple grinds and shapes, oil quench, I can take to final shape before HT without warping). I go to 400 on the belt, then HT. Then I back up to 120 to blast the remnants of the clay off, then 220, 400 belts, then I hand finish 220, 320, 400, 600, 800, 1000, 1500. It's a lot of work, but that's why my knives are "so beautiful." ;)
 
I grind everything to final final finish and hund rub it to 320, after HT I come back in with a worn out 800 grit cork belt loaded with green buffing compound and take the color of it from HT and then go in and start with a 400 grit hand rub than to a 600 grit hand rubbed satin finish,that is it

This can be done with any steel,including S30V.. makes for a very clean finish
Walter Brend turned me onto this ;)
 
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