I'd better bring a big pile of toolbits for practice though! Lets see, I got about 90 1/4 inch Rex AAA. Hate to mutulate them so we better butcher the box of 100 1/4 inch chinese import toolbits first. I will save the mo-max and tantung for the final exam.
What size toolbit is the easiest to grind? I find it 1/4 inch the easiest to grind but not nearly as useful at 5/16. 3/8 works ok on my rockwell lathe but I find they take a lot longer to grind than a 1/4.
chuck
Rough em out on a belt sander. It goes pretty quick
Gunner
Lathe Dementia. Recognized as one of the major sub-strains of the all-consuming virus, Packratitis. Usual symptoms easily recognized and normally is contracted for life. Can be very contagious. michael
Because I rely on the toolbit itself to act as a guide (remember, I *do not* use a tool rest), the larger sizes grind better for me. Mind you, I stop at 1/2" bits. My lathe won't accommodate anything taller. The vast majority of my toolbits are either 3/8" or 1/2". For grooving tools, I tend to favor 3/8". As you suggest, the smaller ones grind a lot faster, but are far less useful, and due to the smaller area in contact with the wheel, are more difficult to grind properly. You can control size much easier when you grind large areas.
Harold
Yep, just don't do the finish grind there. Because a belt tends to rumple at the point of contact, the cutting edge will be rounded----often enough that it won't cut. Belts also restrict you as to tool configuration.
Harold
I have a 6x48 that is pretty good about doing a close to finish grind. The platen is heavy and the BarbKat belts run pretty flat on this grinder. It puts on a pretty square edge as is, but I usually finish up on a wheel as you say.
Gunner
Lathe Dementia. Recognized as one of the major sub-strains of the all-consuming virus, Packratitis. Usual symptoms easily recognized and normally is contracted for life. Can be very contagious. michael
I use mine (6 x 48 Powermatic) for sharpening large drills, having no alternative. If you work carefully, you can avoid the slight rounding that is inherent in *almost* all belts. Needless to say, the tighter one can keep the belt, the less it's inclined to round the edge. Lower pressure on the object helps, too. Belts are far more affective at stock removal than are wheels.. So much so that centerless belt sanders are often used for surfacing round stock in lieu of wheel machines. The end product is not quite as good as if ground by wheels, but more than adequate. I used to buy 1-7/8" diameter 303S in volume for producing metering pumps for the pharmaceutical industry. It was so sanded, and came slightly oversized (.002"/.003") so it could be cut to nominal for a good finish. The sanded surface was rather coarse, and not exactly round.
Harold
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My son cannot grind tool bits with constant angles. There's only one word I have for him and others like him who grind facets. Concentrate.
Regards,
Orrin
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