sharpening a curved iron, diamond review
bill tindall
>Brief Summary: Make cylinder from aluminium, mount in something that will spin it, charge with diamond, rapidly grinds concave edges of irons and tool flutes.
As many know I have been evaluating diamond abrasive for tool sharpening. The advantages are speed and low cost. I have found a new application that works particularly well for an otherwise tedious task.
I have found that diamond charges well on aluminium, particularly the coarse grits. It embeds well and cuts well, but at a finer effective grit size than when charged on something harder like cast iron.
I have turned a variety of sized cylinders that fit my drill press, or lathe chuck of wood lathe (depending on orientation of cylinder that is desired, vertical for irons and horizontal for tool flutes). The diameter should be some less than the diameter of that to be sharpened. The charged cylinder should turn slowly, maybe about 200 rpm so control is easier.
Shown is a LV concave spoke shave iron. Thankyou!! Mr. Lee, as it is the only turely flat iron I have even purchased and hence, its back polished up quickly with diamonds. I started with 60 micron on acrylic which cuts like gang busters. Then finished with 15 and then 1 micron on cast iron. I am finding the coarse diamond (60 midron)does better on a softer substrate, like acrylic. The 15 and 1 micron work ok on acrylic but the tool slides easier on cast iron. I've got it so I use it, but acrylic is cheaper and more readily available until someone realizes a good marketing oportunity and sells cast iron plates(editorial).
The bevel had huge scratches, like what might have resulted from 60 grit grinding. A 15 micron abrasive on aluminium removed these scratches in a minute or two and left a nearly polished surface. Mineral spirits was used to lubricate. I finished with 1 micron on a separate cylinder.