Ceramic Bench grinding wheels

[Ivan Stancioff]

I have a older Stanley 7" bench grinder (1750 rpm) and I am having a hard time finding SG ceramic alumina grain wheels in 120 and 80 grit in 7" diameter. I am looking for suggestions for where i can find them. In my reading about sharpening, I found that the preferred size is 8" and that 6" wheels are too small for a skew.

 

[Brian Gustin]

I have a older Stanley 7" bench grinder (1750 rpm) and I am having a hard time finding SG ceramic alumina grain wheels in 120 and 80 grit in 7" diameter. I am looking for suggestions for where i can find them. In my reading about sharpening, I found that the preferred size is 8" and that 6" wheels are too small for a skew.

Hmm. I'd wonder if the wheel guards are removable? then you might cut a block of wood as a mounting pad for grinder to shim it higher, and mount CBN wheels in 8 inch. Also, 6 inch wheel would not be too small for a skew, where'd you hear that? Only difference 6 inch vs 7 or 8 inch would be the shape of the hollow grind (which would affect the cutting edge angle, which then could be remedied by a less acute angle?)

If it were me and I insisted on keeping the grinder (as opposed to buying a modern low speed one) I'd look into possibility of removing guards and putting CBN wheels on it - Of course, your grinder's arbor size would be a show-stopper if it was not a standard size.... Since CBN wheels are not subject to breaking apart like frangible grinding wheels, the guards should not be too much of a concern when using CBN (or perhaps they could be modified?) If all I had was a 6 inch I'd not be too concerned about skew sharpening - any problems with the hollow grind eventually could be honed away as you hone the skew to re-sharpen. (Can't imagine trying to use a skew fresh off a 120 grit grinding wheel, it'd get dull so fast.... It is why I never bothered trying skews after discovering that it was near impossible to keep them to a fine edge without extensive honing after grinding, once I got CBN wheels, things went much better)

 

[Ivan Stancioff]

Hmm. I'd wonder if the wheel guards are removable? then you might cut a block of wood as a mounting pad for grinder to shim it higher, and mount CBN wheels in 8 inch. Also, 6 inch wheel would not be too small for a skew, where'd you hear that? Only difference 6 inch vs 7 or 8 inch would be the shape of the hollow grind (which would affect the cutting edge angle, which then could be remedied by a less acute angle?)

If it were me and I insisted on keeping the grinder (as opposed to buying a modern low speed one) I'd look into possibility of removing guards and putting CBN wheels on it - Of course, your grinder's arbor size would be a show-stopper if it was not a standard size.... Since CBN wheels are not subject to breaking apart like frangible grinding wheels, the guards should not be too much of a concern when using CBN (or perhaps they could be modified?) If all I had was a 6 inch I'd not be too concerned about skew sharpening - any problems with the hollow grind eventually could be honed away as you hone the skew to re-sharpen. (Can't imagine trying to use a skew fresh off a 120 grit grinding wheel, it'd get dull so fast.... It is why I never bothered trying skews after discovering that it was near impossible to keep them to a fine edge without extensive honing after grinding, once I got CBN wheels, things went much better)

Thanks for that advice. I will check to see if the guards are removable.

 

[robo hippy]

I would not remove the guards. That type of wheel can break and even at slow speeds, you don't want them breaking up. Not sure if any of the CBN wheel makers have 7 inch wheels or not. You might actually call up Norton to see if they can help you.

robo hippy

 

[John Whitley]

I would not remove the guards. That type of wheel can break and even at slow speeds, you don't want them breaking up. Not sure if any of the CBN wheel makers have 7 inch wheels or not. You might actually call up Norton to see if they can help you.

robo hippy

Reed, I believe the proposal was to both 1) remove the wheel guards and 2) replace ALL of the wheels with 8" CBN wheels. Is that still a concern?

 

[stu senator]

Find someone with 8" wheels who is replacing them as they are worn. Should be about the correct size.

 

[Mike Selser]

I ordered 7” wheels for my Baldor bench grinder from Grainger.com.

 

[robo hippy]

I like to keep the inside wheel guard on with the CBN wheels. Main reason is dust control. The metal dust will float around like wood dust. Found some inside a magnetic based lamp box about 3 feet above my grinder. Some one else hung a magnet 10 feet away from their grinder and it got dusty as well. To date, there is no affordable metal dust extractor for woodshops. Only exception would be one of the air scrubbers, but not down where it might suck in sparks. While the CBN wheels will never come apart, the dust is a problem. Many will put rare earth magnets in plastic baggies and that does contain some of the dust, but not all of it. Having the hood on does help control the dust.

robo hippy

 

[Ivan Stancioff]

I ordered 7” wheels for my Baldor bench grinder from Grainger.com.

Thanks, I'll check with Grainger

 

[John Whitley]

To date, there is no affordable metal dust extractor for woodshops.

Fair point, and thanks for clarifying. For what it’s worth, I actually have a metal dust collector base for my grinder that I picked up as a refurb. It helps to a degree, but it’s not enough. I still get metal dust around the base of the grinder like everyone else, which I clean up with a magnet wand tool. Stock wheel guards seem mostly designed to contain wheel explosions, and not to collect dust. Likewise, a grinder platform is great at directing metal dust away from the guards and dust collection.

I think that situation can be improved with a redesigned guard, and possibly a modified platform. I should test the metal dust colletor’s effectiveness with my Dylos, but I’m pretty sure the results will be grim. As it stands, I only use the grinder when turning and I always have breathing protection on (formerly a P100 half mask, now a PAPR). Before doffing that, I turn on the big extractor fan in the back of the shop and let it pull a few cycles of air through.

 

[hughie]

The effectiveness of dust collector for metal dust is down to the velocity of the air movement. Mine does a fair job, not a 100% ,its Jet with 6" inlet and 2hp motor

 

[Lou Jacobs]

Hi Ivan! Good to see you here! McMaster-Carr seems to also have 7” as well as just about every other size wheel you could want.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

PS- as I look them up, most even seem to be shipped with bushings to accommodate various arbor sizes.

 

[John K Jordan]

The metal dust will float around like wood dust. Found some inside a magnetic based lamp box about 3 feet above my grinder. Some one else hung a magnet 10 feet away from their grinder and it got dusty as well.

That may have been me that described that. I have a bunch of magnets on the back side of my bandsaw, the side away from the grinders at least 10' away. I found all the magnets coated with fine black dust. Try turning down the room light and sharpen with CBN with one bright task light. You'll be able to see tiny little HSS particles floating in the air. Probably not good to breathe.

Many will put rare earth magnets in plastic baggies and that does contain some of the dust, but not all of it.

I do that, with strong magnets under the wheels. The plastic bag makes it easier to clean the glob of steel dust off the wheel.

But WARNING, WILL ROBINSON! Don't be stupid like me. I once let a big "hairy" glob of the extremely fine steel dist build up on a powerful magnet under and a bit to the side of an 8" 600 grit CBN wheel. CBN wheels produce almost no sparks compared to conventional grinding wheels. But you can occasionally see a tiny spark.

I was happily sharpening tools and happened to look down at the big glob of steel dust. Deep inside was an orange glow! If you don't know, steel dust and even very fine steel wool will burn nicely. The orange glow at the grinder was a pea-sized blob of molten steel apparently ignited by one of those tiny, almost invisible, sparks. I quickly took it outside and dumped it in the gravel drive. All my grinders are on stainless steel commercial shelves, but if left to burn at the grinder there was a possibility the blob of burning steel could set some 3/4" plywood on fire and burned down the shop. You can be sure I now check it every time and clean off the dust often.

One of my sci/tech friends was excited about the fine steel dust so I now save it for him. If you want some fun outside, mix some fine aluminum (or sliver or other) powder with iron oxide or steel dust or fine steel wool and light it. (for some reason I have 2 quarts of fine aluminum powder.) The combination can make an intense white-hot thermite reaction, according to my reading even used at one time to weld railroad rails together. As a kid I burned steel wool in our basement and it dripped molten iron which splattered on the concrete floor. Sometimes friends and I reminisce about things we did when growing up and are surprised we are still alive...

JKJ

 

[Tom Gall]

Sometimes friends and I reminisce about things we did when growing up and are surprised we are still alive...

I think many of us can say that ... especially us "older" guys!

 

[robo hippy]

I can't remember John..... I did have one lamp with a magnetic base on it up above my lathe, and still in the box. I eventually opened it up and found metal dust on the magnet. As of yet, there is no simple dust collection system that is affordable for the home shop. I would think one of the air scrubbers would work fine, if it was set up with a hood of some sort, but away from the grinder so it does not inhale sparks.

robo hippy