Why Grind Bevels Multiple Times?

[Hugh Buchanan]

I tried an experiment last week. I profiled a blade and immediately heat treated and tempered it. I polished the edges and the flats with 320/600 grit belts. I would have gone farther if I had higher belt grits. The 600 grit belt left the blade shiny, almost mirrored, but with streaks, I hand sanded with 1000 grit paper, but decided that it looked better after the 600 grit belt.

After getting the flats to what I was going to consider finished for this experiment, I ground the bevels with a 320 grit belt. By finishing the flats before grinding the bevels, the grind lines and plunge lines were sharp and crisp. The results were as good as anything else I have done (I'm a novice) and I think you would find the blade to be acceptable in every way. I don't think that I spent more time at the grinder because of the high grit. The steel came off the blade quickly. I only touched the bevels one time in the process.

The conventional process begins before hardening, with belts containing grit you could use to pave your driveway. I am wondering if there is a good reason to start coarse, before heat treating, going up to finer grits in stages before and after HT.

I am using an Origin Blademaker Grinder with a 1 hp motor and aluminum oxide belts made by Combat Abrasives. I use jigs for grinding flats and bevels.

What am I missing?

 

[Dr Heelhook]

You'll probably get better answers in the knife maker's forums.

 

[marrenmiller]

I think a lot of makers do grinding before heat treating because you're going to be less likely to screw up the temper by overheating during grinding.

 

[marthinus]

As a collector there is nothing more appealing to me than a hand satin finish with no scratch marks when you look “through” the hand satin.

One of the best hand satins I saw recently is a 2000grit over a complete mirror my Neill Schutte on a Loveless Junior Bear.

You can see yourself “through” the hand satin but the satin is there.

One wont get that on a 600 grit. I go to 1200 that gives me a mirror. Then satin on 1000grit for a working knife. Otherwise complete mirror with a buff and then hand satin to 2000.

Rob Brown had a good tutorial on how to do this.