Sanding?

Jason Fry

Knifemaker / Craftsman / Service Provider
Joined
Jun 5, 2008
Messages
2,888
What's your sanding technique? Do you move the paper, or move the blade? Do you use a jig, a block, or what? Do you use different grits in different directions, or all the same direction? What's your grit sequence, both pre and post heat treat? Trying to become more efficient in my operation, and produce better knives.
 

A C Richards

Knifemaker / Craftsman / Service Provider
Joined
Apr 14, 2006
Messages
3,815
Rough grind with 40g. Then hand file with shoulder jig in place. After draw filing sand with a block with 150g. HT then 150 again,220, 400, 800, 1000, 1200 and then depends on what I am doing. Each gets a different direction until I hit 1000 then all the same. Always back it up with a piece of wood or soft metal, alum, brass or copper. Soft items like fingers will follow imperfections and cause problems. I use a harder rubber backer for final finishes.
 
Joined
Sep 19, 2007
Messages
2,819
...After draw filing sand with a block with 150g. HT then 150 again,220, 400, 800, 1000, 1200 and then depends on what I am doing.

Interesting... I thought that you were supposed to finish the blade as much as possible BEFORE heat treating it... I didn't get rid of the file marks in one of my blades before HT and I had a hell of a time getting them off after the steel hardened. Is there any reason you shouldn't go all the way up to... let's say... 400grit before you HT? All my HT is done like in the old days (coal forge, heat until red, quench in engine oil, temper in the kitchen oven, etc) so I usually need to get rid off all the black gunk (from the burnt out engine oil) after quenching it. The smoother the surface, the easier is to get all that crap out!

...Always back it up with a piece of wood or soft metal, alum, brass or copper. Soft items like fingers will follow imperfections and cause problems.

Truer words were never spoken. I screw up badly once. I was using a file as backing for the sandpaper and it was all good while using cloth backed sandpaper (220 and rougher) but once I reached 400g... I somehow managed to rip the paper and I put the deepest scratch ever on my near finished blade. Dumb dumb dumb... Now I use a piece of home made pseudo-micarta or aluminum.

I need to get one of those ScothBrite wheels for the drill... they might be useful to put satin finishes on the blades shaving up time from hand sanding procces (I don't even have a belt grinder).
Mikel
 
Joined
Jul 14, 2004
Messages
2,623
I do all grinding after heatreat.heres what i do..,50 grit to rough in bevels,220 grit,400,600.then i use a well broken in 400 grit cork belt,then a broken in 600 cork belt,both loaded with compound.blade is close to a mirror after this,only with visable scratches from cork belts.i just got a bunch of 3m felt backed paper..,this stuff is killer! after mentioned grinding,i hand sand starting at 400,600,100 and then back to 600 using a fresh piece each stroke.i also made a 2" and 8" diameter micarta block to fit my hollows.

this took me about 10 minutes to hand rub out the other day after this grinding technique!

rub2.jpg


See my screwdrivers hanging on the wall,in the reflection :)
 

A C Richards

Knifemaker / Craftsman / Service Provider
Joined
Apr 14, 2006
Messages
3,815
You discovered why you try to get rid of file marks. If you go much finer than 150 when ht in a forge you will just have to go back and re-do it cause of the scale form the oil. It is not to say you can not go finer, just the way I do it.
 
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