At the grinder, what's the last grit you use for shaping?

Patrice Lemée

Patrice Lemée

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Aug 13, 2002
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Or if you prefer, which grit only removes scratches without affecting the shape/grind of the knife?
I ask because I realized yesterday that I probably leave too much shaping to be done by higher grits.
For example, let's say I am doing a flat grind. I move the grind closer to the spine with each grit, starting with 36, 60 then 220. I sometimes still leave a tiny bit for the 400 grit but always end up cheating because 400 has a hard time removing much. :(

I think that I should take it all the way to the spine at 220. Maybe even lower than that? :confused:

So where is the turning point for you guys?

PS: I think this would be a good thing for new makers (me included) to know. They are the one most likely to be scared to mess up with larger grits and leave too much for the higher grits.
 
I go to 220. I treat 400 as just a scratch remover. I do probably 95% of the roughing with 36-50 grit blaze, though. Life is too short to fight a fine belt into removing much metal.
 
60 grit, because I jump straight to 400 grit gators. Given the thinness of the blades I'm working on, I should really hog with an 80 or 120 grit though. I usually end up losing about 1-2mm of width because an edge thats been hit by 60 grit is no good.
 
80 for shaping then 220 and 400 for removing scratches then to hand sanding.
 
Salem Straub said:
I go to 220. I treat 400 as just a scratch remover. I do probably 95% of the roughing with 36-50 grit blaze, though. Life is too short to fight a fine belt into removing much metal.
Click to expand...

Same here, except lately I've been skipping from 150/160 right to 400.
 
hog wit 50 then i clean up and flatten the grind with 80 blaze if things are looking good i ll see how the 120 belt looks (by this point often im under .010 edge thickness). then i do all my clean up with gators

when im finished the knife is often in the .005-.007 range (or thinner if need be for the order )
 
36, 60 then 80. I use 120 and 220 for scratches then go to hand sanding. Im too scared to use anything higher than 220 on the grinder. Although for handles I go to 320 before I switch.
 
I watched a grinding demonstration at a hammer in. The sage advice of the master smith was, "Don't grind on a polishing belt." It takes too long and the heat builds up. I stop grinding at 80 grit.
 
Recently I've been trying to get a solid handle on this myself, Patrice. It seems to me that anything past 120/150'ish doesn't do a whole lot of material removal, so I've been trying to do 90-95% at 60x, 5'ish% +/- at 120x, and count on almost none beyond that. I used to try to doing more at higher grits, but it just seems futile.
 
Using belts that are too fine for the grinding job at hand just produces poor results. I still want to use too fine a belt at times but will back up as soon as I see "things" don't seem to be working out. Frank
 
I've started using 36 grit for hogging and then switching to 60 grit to finish up shaping and get the bevels pretty much done. I then switch to a 120 grit gator to finish up any final shaping but often leave the very last bit of shaping to a 220 post HT. For example, my tank area might get a little more final tuning after the scales are put on as I adjust the precise shape of the whole package, but I'm not going to try to change a blade profile significantly. Since I started I've REALLY cut down the amount of time spent with belts finer than 120 grit and even the 120's see limited use relative to what I was doing. I found I was just wearing out belts by trying to do more than they were meant for. 36 and 60 do great at removing material for me, after that I'm basically removing scratches or trying to make such a small change that they'd be too hard to control and leave scratches as deep as the change I'm making. Suddenly my belts last much better.

I'd say that once I move to the belt grinder, 95% of the material removed is removed with the 36 grit belt. Another 3% is the 60 grit, then the remaining 2% is the rest plus hand sanding.

I also started doing much more complete profiling with an angle grinder. Ideally I'd use a band saw but I don't have one, so I do my general cut out with a cutting wheel then switch to a grinding wheel and get a lot closer to my lines. They're a lot cheaper and faster for that than belts. In the past I was only cutting out the general shape, leaving as much as a quarter inch of excess in areas due to the difficulty in matching curved areas. While faster for that step it was much slower later and was really eating up my 36 grit belts.
 
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