Prior to the start of the June meeting a few of us were talking about the grinding wheels in stock at Woodcraft. There is so much new information out there that a little refresher is in order.
I am only going to be writing about wheels for woodturners. Since most of us use tools made with high speed steel ( HSS ) I will narrow my comments further.
Wheels are made in any number of hardnesses running from A to Z and grits.
For us the recommended hardness is H, I , J or K ( K being harder than I ) and a grit between 60 and 80. Always grind at low speed ( 1720 RPM ).
The other letter you might find on a wheel is V which means it is vitrified. There are basically two kinds of wheels, vitrified which is used for precision work and resin or organic wheels which are used for rough grinding and typically come in grits as low as 16. So we are looking for a grinding wheel on the softer side H,I,J,K and vitrified ( example 80 grit-KV ) .
Now for color to make it simple. White is an excellent general purpose wheel. We should look for blue or pink. Remember the game is to sharpen our tools while creating the least amount of heat while removing the least amount of material. Go for a wheel with a ceramic content. Norton recommends their 3X grinding wheel which is 30% ceramic and sells for around $50.– .
If you want to go for the big bucks and want a wheel that doesn’t clog as quickly ( less dressing is required ) , Craft Supplies USA sells the Norton SG wheel. I called them and verified that the 80 grit wheel shown in the catalog for $105.– is a 5SG meaning it is 50% ceramic. As for me, the Norton blue 3X meets all my requirements.
Remember our next meeting is on Wednesday July 16th, 7PM at Woodcraft . We need a better show and tell turnout so next month there will be no president’s challenge. Please bring a special piece. Don’t worry, there will be a special challenge for September.
Bob // Robert F. Greenberg, President