Tormek Anglemaster - can't set bevel angle
Hi guys,
I installed a Tormek rig on my low speed grinder with 8" CBN wheel. I'm having trouble figuring out how to accurately set an angle with the Tormek Anglemaster (WM200). Im using the SE77 straight edge jig to hold the chisel. (It's fussy but it seems to work fine.)
1. I set the angle to 25* and ground a chisel. It was great. Except that my PROTRACTOR told me the final bevel was 30*, not 25 as I'd set it to be. Hmmmm?!
2. Next I set up and ground a 15* bevel on an Aldi I use for paring. Got a lovely, even grind and a sharp tool. But the PROTRACTOR says the bevel is 20*, not 15*. Imagine my cursing!
Two bad angles, each offset by 5* from what I set up to grind. That protractor has always been accurate. And Tormeks have a good reputation. So this has got to be me not setting the Tormek hardware up right, right?
3. So I go watch 3 videos and confirmed I know how to set the WM200.
4. Then I take off the CBN wheel and measure the diameter. Turns out it is not precisely 8". It is 7 7/8" - that's 200 mm, which means the actual wheel diameter is 3 mm smaller than the 8" diameter I'd used for steps 1 and 2. So I reset the WM200 for 200 mm.
5. I put the chisel from step 1 back in the straight edge jig, resting the bevel so that the bevel is touching the wheel at all points. (This should let me use the WM200 to see what bevel the grinder is set to cut.) Good news - now the WM200 tells me it's set to cut a 30* bevel, which matches what the protractor says.
6. But when I repeat step 5 using the chisel from step 2, the WM200 still tells me the bevel is 15*, NOT 20* like the protractor says.
I've checked and re-checked step 6 with no change. That bevel really is 20*. Why does the WM200 keep telling me it should be 15*? I've gotta be missing something obvious. Anyone see what it is?
Thank you!
Fred