Grinding wheel grits

[Richard Dooling]

I'm curious as to what grinding wheels people favor in a dry grinder. What grits, brands and compositions? I currently have a no-name gray 60 grit and a no-name white 120 grit. Much to my surprise I find that recently I've been using and liking the 60 grit more. It cuts fast and the "coarseness" of the stone doesn't seem to have a significant effect on the time it takes to hone on the bench stones. Maybe it's my imagination but it also seems to cut cooler.

My system is to establish the primary bevel on an 8" dry wheel. Then I work from medium diamond through fine ceramic stones. I finish up with green honing compound on a maple block. Since the blades are hollow ground the honing process is very fast.

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[Robert Rozaieski]

The coarser the better in my experience. Coarser wheels grind faster and cooler than fine wheels. I currently use a cheap 6" "coarse" labeled wheel in a hand crank grinder. My guess is that the wheel is somewhere around 60 grit. I have a $$$ fnacy white wheel in my high speed grinder but it's somewhere like 120 grit and I don't like it. Too slow and heats up the steel too fast so I don't use it anymore. The hand crank with the "coarse" wheel is just as fast as the high speed with the 120 grit $$$ wheel but the hand crank doesn't burn the steel. I don't even need to cool the tool in water anymore when grinding with the hand crank.

Coarse is good. I think I remember reading somewhere that Larry Williams (of Clark & Williams Planemakers) likes something like 36 grit wheels.

[dan sherman]

I'm curious as to what grinding wheels people favor in a dry grinder. What grits, brands and compositions?

what do you plan to be grinding with the wheel? The type of metal being ground plays a big part in wheel selection.

this pdf has some god info. http://pacificgrindingwheel.com/index.php?option=com_docman&task=cat_view&gid=81&Itemid=71

[Richard Dooling]

what do you plan to be grinding with the wheel? The type of metal being ground plays a big part in wheel selection.

this pdf has some god info. http://pacificgrindingwheel.com/index.php?option=com_docman&task=cat_view&gid=81&Itemid=71


Of course I should have mentioned what I'm grinding - sorry.

This is setup to establish the primary bevel on bench chisels and hand plane blades. These are all over the map in terms of metal composition – old Stanley and Sargent planes, a variety of old chisels. Newer LN and LV plane blades and one Hock A2. I find that I’m not overly fond of working on the harder steel though I do appreciate how lond it holds an edge. I'm slowly getting into turning so I’m also grinding turning tools.

I occasionally do some rougher work on it like lawn mower blades.

That's a great resource you linked to. I've saved the PDF to my library. Thanks

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[dan sherman]

IMO you should have 2 or 3 different AO wheels one for the hard stuff (G or H grade), one for the medium stuff (I or J grade), and one for the soft stuff (k or l). grit wise I would go with 46 or 60.

[Bob Barkto]

Norton 3X Blue Wheel - Grade I - 46 grit. They cut fast and cool and have decent wear.

To grind hss turning tools the same wheel in a finer grit (80 - 120) - K grade. These are harder wheels so won't cut as cool on the carbon steels, but hold up much better on the tough hss.

These aren't the most economical choices for rough grinding of odds and ends, for that you might want one of the cheap gray wheels. Around 60 grit seems to be a good compromise for speed and decent finish.

[Thomas Crawford]

So, my method is to go to waterstones after the grinder. Is it too much of a jump to go from the 46 grit grinding wheel to a 1000 grit Norton stone? I hate my 220 grit stone with a passion and want to avoid it (goes out of flat too quickly).

I've been using the 120 grit grinding wheel and it takes way too long, but I also don't have any issues going to the 1000 grit stone afterward.

[Richard Dooling]

Thanks Bob, you have pretty much confirmed my decision.

Definitely getting the 46 grit Grade I Norton 3X for most non HSS edges. I may have to wait (been jes’ a bit over my tool budget this month:rolleyes:) on the Grade K. I’m thinking that for turning tools and with just one grinder the 80 grit wheel Grade K is the best for now. Thoughts?

[dan sherman]

actually the "I" would be better for hss, the lower the letter the better it works on hard materials (assuming everything else is constant.).

check out the first page of this grinding wheel selection guide from Norton.
http://www.ind.nortonabrasives.com/media/documents/S0000000000000001035/Wheel%20Selection%20Guide%20Brochure%207861B.pdf

[george wilson]

Be advised that the faster a wheel cuts,the faster the wheel also wears. The grit breaks away,exposing new,sharp grits. I use Norton white wheels. If I recall correctly,cheaper imported wheels just do not stand up well. I also use a very coarse wheel,but having a Wilton square wheel grinder,it is so much faster,and cooler, that I seldom use the wheel grinder any more.

[Bob Barkto]

1000 grit should be fine.
It might take a few more swipes but you won't have to deal with the 220 madness.

I've used waterstones in the past and did start at 800, but 1000 isn't a great difference so you should be fine with that.

I think going from 120 to 46 will more than make up for some small amount of extra time spent on the finer stone.


So, my method is to go to waterstones after the grinder. Is it too much of a jump to go from the 46 grit grinding wheel to a 1000 grit Norton stone? I hate my 220 grit stone with a passion and want to avoid it (goes out of flat too quickly).

I've been using the 120 grit grinding wheel and it takes way too long, but I also don't have any issues going to the 1000 grit stone afterward.

[Bob Barkto]

You raise a good point.
In theory, yes, a softer wheel for harder material is the rule of thumb.
In practice, the I seems too soft to me. Most of the really hard hss and other hard alloy tools just eat them up.

A K grade is pretty hard but the hss tools can take it. A K grade will keep it's shape much better and last a lot longer. Also, when just touching up a turning tool the harder wheel is a little more forgiving as it won't slough off the steel so quickly. I think that's a good trade for the reduced cutting efficiency of the harder wheel.

In a production environment where production speed outweighs wheel cost and dressing is done automatically I'd probably use the I just because it will probably cut a little faster. It is something that needs to be determined on a case by case basis imo.




actually the "I" would be better for hss, the lower the letter the better it works on hard materials (assuming everything else is constant.).

check out the first page of this grinding wheel selection guide from Norton.
http://www.ind.nortonabrasives.com/media/documents/S0000000000000001035/Wheel%20Selection%20Guide%20Brochure%207861B.pdf

[Bob Barkto]

80 grit should be fine. You might want to keep the 120 you have for now and see how it works for you. It will work well enough on the turning tools, just probably isn't optimal.

I'm not a prolific turner so don't spend too much time sharpening turning tools. I do know some good turners feel an 80 grit is just right, others will say go to a 120. Some will say 60 is ok.

I used a softer 120 before I got a harder 80 grit and I do notice the difference for the better, but the 120 got the job done.


Thanks Bob, you have pretty much confirmed my decision.

Definitely getting the 46 grit Grade I Norton 3X for most non HSS edges. I may have to wait (been jes’ a bit over my tool budget this month:rolleyes:) on the Grade K. I’m thinking that for turning tools and with just one grinder the 80 grit wheel Grade K is the best for now. Thoughts?

[Richard Dooling]

Thanks to everyone for their inputs. Just ordered the 46 grit grade I and I'll keep the 120 grit white wheel for HSS for now.

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