Thursday, November 03, 2005

Specialty bowl-gouge grinds

When you purchase one of those 'signature' bowl gouges with a fancy grind on it, what exactly are you buying? A piece of round steel with a flute ground in it, sharpened carefully to match a profile developed by a master woodturner.

A few sharpenings later, what do you have? A slightly shorter piece of round steel with a flute ground in it, sharpened as best you can to match what you think it looked like a while earlier. Even with a sharpening jig, it may not be very long before the edge of the tool bears little resemblance to how it was when bought. One of the fundamental skills involved in sharpening is knowing the exact shape you are aiming for.

My advise to anyone who has spent money buying a gouge with a speciality-grind is to either take close-up photos or careful drawings of it before you use it or take it to the grinder. I would recommend carefully recording the side profile, top view and bottom view.

The only supplier I know of who has done this right is Melvyn Firmager. He supplies a set of pewter models of the custom grinds he sells for natural edge and hollow vessel work.

One of the first things I explain to students who ask about purchasing bowl gouges is that what you are really buying is the flute, rather than any fancy grind the manufacturer has applied. The only real advantage I can see for buying such a tool is that it can save you quite a bit of work grinding the profile in the first place. Melvyn once told me that he grinds his signature tools before they are hardened, which I guess must make the job easier and faster.


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1 comment:

Darryl Masterson said...

that's a good idea about taking pictures of tools before using them.

I might even take that into consideration for any hand planes that I may pick up in the future. take a couple pics when the blade is set correctly.... hmmmm...