Getting a good edge on a wood lathe tool is
one of the great difficulties for a beginning woodturner and an ongoing concern
for intermediates and experts. While the grinder is the tool of choice for
woodworkers sharpening tools for wood lathes, getting it set up with the
correct wheels can be a confusing challenge. It need not be with a couple of
simple steps.
First it is necessary to move in thinking
of the grinder as a sharpener. Many people come to woodturning from general
woodworking where the grinder is used to remove lots of metal in a hurry so as
to grind away nicks and breaks in chisels, plane irons and the like. Water
stones and honing implements are used for final edges. Woodturners move from
the grinder to the wood. Most shop grinders are not set up for this and the
problem is largely the wheels.
Thus the second consideration is to replace
the grinder wheels. While it is agreed that since woodturners generally use
high speed steel tools they should have aluminum oxide wheels, there is a lot
of confusion in the catalogues as to what color wheel to get and what bond to
have. The color reflects individual manufacturers attempts to make choosing
between grades of their particular wheels and has little to do with other
wheels on the market. Consideration then should be given to grit and bond.
The bond of a wheel refers to how friable
the material is that holds the aluminum oxide together. More friable bonds
allow the material to break away quickly thus leaving a sharp cutting and
cooler grinding surface. Unfortunately, the most friable bonds manufacturers
recommend for woodturners groove, pit and wear quickly requiring a lot of wheel
dressing and expensive replacement. Thankfully, almost any aluminum oxide wheel
generally available to the home market is sufficiently friable for good
sharpening with good wear so making sense of the friable numbers of bonds is
not necessary. Just get a good wheel.
Third is consideration of the grit. While
it may encourage argument, a good setup is a fast cutting wheel of about 46
grit on one side of the grinder and a sharpening wheel of eighty to one hundred
on the other. With a good jig especially, this will meet all the shaping and
sharpening needs of the woodturning shop.
Simply put, a couple of inexpensive
aluminum oxide wheels of appropriate grit will give a lot of sharpening
satisfaction and help to make a lot of shavings for a long time to come. Keep
it simple and keep it fun.
Darrell Feltmate is a juried wood turner
whose web site, Around the Woods, contains detailed information about wood
turning for the novice or experienced turner as well as a collection of
turnings for your viewing pleasure. You too can learn to turn wood, here is the
place to start. Wondering what it looks like? There are many free videos on the
site dealing with everything from sharpening to making a bowl.
For full instruction in getting your tools
sharp and in particular how to make a very inexpensive sharpening jig, check
out making and using the sharpening jig. Using only short time, some shop
scraps and a couple of dollars you can make a jig that will perform like a
hundred dollar tool and easily sharpen your wood lathe tools