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daved20319
12-13-2010, 04:45 PM
Just bought a grinder, need to replace the gray wheels with white, but don't know what grits I should use. Will be using it primarily to grind HSS lathe bits, it's a 3600 rpm 8" Ryobi. I know, I know, but a Baldor is WAY out of my price range :-). Or would one white and one green wheel be a better setup? Thanks in advance, gents.

Dave

Lew Hartswick
12-13-2010, 05:02 PM
At school we have one grinder with a pair of 60 grit and the other with
a 100 and on the other end a drill bit sharpner. The wheels are Pink
aluminum oxide and the sharpner is an old Atlas (works great).
Of course the grinders are Baldor but the combination of 60 and 100
seem to work good for the lathe bits etc that I grind. Do have access
to a Glendo with diamond for any real polishing. :-)

tdmidget
12-13-2010, 06:21 PM
Pink means it was dyed. Pure aluminum oxide is white. For grinding HSS off hand it doesn't really matter as you can't overheat it so what ever removes material at a rate you are happy with and leaves a decent edge. You should stone the final edge anyway so a 60 grit wheel is probably OK. I would use Norton 38A for tool steels as it is the most frangible and therefore faster cutting. You should have a green Silicon Carbide wheel for roughing Carbide tools and finish with a diamond file or wheel.

mf205i
12-13-2010, 06:24 PM
For finish work you are on your own. For a roughing wheel I would recommend a pink wheel from Enco. For hand held roughing, get the 46 grit in the I hardness. I use the 7 x 1/2 inch wheels on a 6-inch, 3450 RPM grinder. These are 1 bore wheels so you will need to make a spacer and you could have some guard issues but I assure you that it is worth the effort. Be prepared to be amazed as to what a proper wheel will do.
http://www.use-enco.com/CGI/INPDFF?PMKANO=247&PMPAGE=66&PARTPG=INLMPI&PMITEM=317-1113&PMCTLG=01

Black_Moons
12-13-2010, 07:57 PM
I'll note my 8" 3600rpm grinder feels wayy too fast and vibrates wayyy too much reguardless what iv done with it, Other then the time I bolted it to 200lbs of steel.
The 1800rpm ones cost a lot more.. But I think its likey worth it. -_-;