Learning the art of surface grinding

Here's a couple charts from Norton and Carborundum that should make wheel selection, and trouble shooting finish a bit easier. Different manufacturers use different codes, but the principles still apply. As for brand selection I prefer Norton, Carborundum, and Radiac, in that order. I have tried other brands over the years, but keep coming back to these 3. They seem to have the best overall quality as far as runout, balance, grit sizing, and bonding. There may be others that I haven't tried that are just as good. I've tried a few GCW (Camel) wheels over the years, but wasn't impressed with the balance.

A general rule of thumb is the harder the material, the softer the wheel. The 46 H wheel may do the trick, or you may have to go to an 80 grit, or even a 120 grit if you're looking for a mirror image finish. I would also consider a F, G or even softer wheel.. There have been times when I've even had to go to an A or B for harder materials. The trouble with the softer wheels is they are messy, don't last nearly as long, and need to be dressed more often. When dressing make sure you use a sharp diamond, rotate it often to keep it sharp, and don't remove more than .001" or so per pass.
 

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  • Norton Toolroom Selection Chart 7505.pdf
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  • Carborundum Wheel Selection Chart.pdf
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That’s helpful.
From what I have gleaned from this forum and other sources, wheel choice can be very controversial.
Thank you projectnut.
 
Janderso said:
That’s helpful.
From what I have gleaned from this forum and other sources, wheel choice can be very controversial.
Thank you projectnut.
Click to expand...

I would agree. Sometimes just the quirks in a particular grinder will make finishing more of an art than a science. My grinder is going on 65 years old. Over it's life it's had a couple sets of bearings, and some motor reconditioning. Who knows if today it runs exactly the same as it did in 1954. I wasn't there when it was new. All I know is that I can still get a good finish. Sometimes it just takes a little different wheel, and a slightly different feed rate.

For more difficult material I usually wait for a full moon, and make sure I circle the machine only in a clockwise direction. Not that I'm superstitious or anything.
 
That scalloped finish looks like it was caused by an out of balance grinding wheel. Or the table on the SF is not translating smoothly. Or bad bearing(s) in the spindle. Or drive belt (if it has one?) is too tight, telegraphing motor noise.
 
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Are there any advantages to type 5 recessed wheels vs. the standard type 1?
Ok,
Done for today. Merry Christmas
I just got the word.
 
When you harden steel, it moves around and the dimensions change. Harden it first. You will also have better luck with finishes when using hardened steel. When you notice scallops, look for wheel not dressed enough, not dressed sharp, wheel out of balance, problem with the wheel mounting, and play in the spindle bearings, in that order until you get good results.
 
Janderso said:
Are there any advantages to type 5 recessed wheels vs. the standard type 1?
Ok,
Done for today. Merry Christmas
I just got the word.
Click to expand...
No personal experience with recessed wheels, the advantage that I see is being able to grind a wider surface in one pass where the spindle will not allow an adapter wide enough to hold that thickness.
 
The "Handbook #19" answered my question as to type 5.
Clearance only, no other advantage.

Chips and more, I would agree with the out of balance wheel. I haven't been able to find a quality. Norton has the Medalists line but I haven't been able to find a source yet.
I can see lateral run out. I can't understand why the finish improves after a dress with the bad wheel.
I am going to have to dress the sides or junk the wheel.
 
WHAT? Are you trying to tell us you cant just slap the warped part onto the mag-chuck, turn on the power and within minutes that warped part magically turns into a flat part??? :bawling:
 
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Janderso said:
The "Handbook #19" answered my question as to type 5.
Clearance only, no other advantage.

Chips and more, I would agree with the out of balance wheel. I haven't been able to find a quality. Norton has the Medalists line but I haven't been able to find a source yet.
I can see lateral run out. I can't understand why the finish improves after a dress with the bad wheel.
I am going to have to dress the sides or junk the wheel.
Click to expand...
Learn how to balance a wheel. There are various plans and instructions online for shop making wheel balancing tooling. Or spend a bunch of money for one made by a grinder tooling maker.
 
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