Carbide Tool Grinder Wheel Choice

I picked up a nice Rockwell carbide tool grinder from a local machinist for $75.00. One of the wheels is a diamond type and the other is a green wheel in very poor condition? What would be a good choice (type and make) to replace the green wheel. I will be occasionally sharpening (touching up) carbide tools, but since making my tangential cutter, I may try my luck with some cobalt/HSS tools also. Is there a compromise or is going green the way to go?

Can a green wheel be dressed square again?

No suggestions?

My preference is to have the green wheel on a pedestal grinder. I save the carbide cup wheel grinder for diamond wheels only, with a provision for drip feed solvent to keep the wheels from loading. My dos centavos.

If you are hoping for a wheel to do both carbide and HSS, there is no good option/compromise.
If the question is about another wheel for carbide, 75% concentration, 220 grit diamond is a fair all around starting point. (I tend to get 100% concentration, myself, but 75% is often recommended)

Yes, you can dress a green wheel with a diamond, same as any other wheel.
Be aware that green wheels don't actually "sharpen" carbide - The erode the binder between the carbide particles so it falls out, eventually leaving an exposed edge of grains and microchips. If you use any carbide tools at all, the cost will quickly become much higher for green wheels, than for just getting a diamond wheel or 2 and using it properly. Especially in this day of cheap imports.

If the question is what kind of wheel to do HSS on one side of the grinder you already have a diamond wheel on the other side, then start with a 46 or 60 grit, J hardness, moderatly porous 38A (white) wheel. The 38A will be the coolest grinding for HSS. If you do not perceive it as "tough" enough, move to a 32A (grey) wheel.

Green grit wheels do have application for grinding cast iron and some similar applications. Also,I used to run an old Fitchburg cylindrical that had a 20" green wheel, we spun down port tools after re-tipping them with new carbide in any broken pockets. Seems like I often eroded/dressed 1/8" -1/4" of that huge wheel in one night shift. But final shaping and sharpening was all done with diamonds on the T & C's or Harig.

PS, anyone who is grinding carbide, even in small amounts, owes it to themselves to read up on the health issues of the dust and the skin issues for absorbance with coolant.

smt

smt,
Should a green wheel, silicon carbide, or an aluminum oxide wheel be used to clean up the mag on a surface grinder? I was thinking green wheel with a coarse dress as the aluminum oxide wheel loads up quickly.
And grinding with coolant.
John

jhruska said:

smt,
Should a green wheel, silicon carbide, or an aluminum oxide wheel be used to clean up the mag on a surface grinder? I was thinking green wheel with a coarse dress as the aluminum oxide wheel loads up quickly.
And grinding with coolant.
John

Click to expand...

Aluminum oxide. The green wheel will wear rapidly. If your Aluminum oxide loads up that rapidly something is wrong. You should only be removing a few tenths. What is the wheel, depth of cut, Coolant?