advice on grinders

C

chris_mayor

Joined
Jan 20, 2014
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i've been making knives for a couple of years and in that time all my grinding has been done on a 2x72 belt grinder/ buffer combo. i recently read a book on knife making and the writer does his grinding on a 10" grinding wheel then finishes them on the belt sander. it might seem obvious to those with experience on a grinding wheel but since i've never used one , i'm wondering if it would save me time to purchase one? and is the time saved enough to justify the cost of a grinder ? if so, can anyone recomend a good grinder ?
 
It seems to me as if you've been reading "Step by Step Knifemaking" by David Boye. A good book and some very nice work, but some of the methods employed are a bit peculiar.

Grinding with a stone wheel generates a lot of heat. You will be fighting that. Grind stones tend to get unbalanced pretty easy, requiring dressing, and you'll be fighting that. Grind stones wear smaller with time, while the 10" contact wheel on your belt grinder won't. You'll be fighting the difference in diameter at some point. Stone grinding wheels actually tend not to remove material as aggressively as a good grinding belt, so you'll have to be using a 2hp+ monster to be hogging much.

The main thing to commend the bench grinder is that you'd spend less money on belts if roughing on one. If your time and sanity are worth much to you, and if you already have a belt grinder, I'd recommend sticking with that for roughing. If you must use a bench grinder, relegate it to profiling- if that. Of course, what are you going to do with your worn out "profiling" belts if you do that?
 
I wonder if he was talking about a stand alone disc sander or a contact wheel for the belt grinder?I have an 8" contact wheel for the 2x72,and it eats metal like nobody's business.
 
thanks for getting back to me. and your right that was the book i just read. the reason i'm digging around is that i seem to spend much longer rough grinding then the guys in several books i've read ,sometimes like six hours, in the books they grind out several in a day. so is the problem that i'm leaving to many hammer marks and scale ? or should i be going through more then one 24 grit belt per knife ? any thought would be appreciated.
 
How you use your belts makes a big difference. After forging a quick clean-off with an angle grinder to get most of the sclae will help your belts last.
Also, 2 or 3 normalizing cycles plus some subcritical annealing cycles will really help your steel to grind more easily after forging.
Using an old belt to start your grinds with, grinding down to the edge at a steep angle before switching to a newer belt and grinding the bulk of your flats helps your grit not get stripped from the belt too soon.
What horsepower is your grinder? It's easier to hog with 2+ horsepower.
As your skill and confidence increase your roughing will speed up, too.
 
i'm using a 1 hp grizzly grinder buffer combo, and thanks for the advice i'm going to try all of those .
 
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