Old grinding stones

torqueman2002 · Mar 28, 2017

The purpose of this thread is to bring to light the potential dangers of using vintage/old grinding stones found on used bench grinders.

As many of you know, there are several threads about vintage grinders - Craftsman 'Block' grinders in particular.

Also, many readers are probably familiar with the 'ring test' to determine if the grinding stone has unseen flaws/cracks.
See: 1, below.

I have had questions about my practice of destroying vintage/old grinding stones, that I find on CM Block grinders.

I do this, because vitreous stones are susceptible to moisture damage. The bonding material can become degraded, and the stone can come apart at speed.

"Vitrified wheels may be sensitive to repeated temperature variations. Irregularly absorbed moisture may throw the wheel out of balance. Consequently, it is most important that wheels are carefully handled at all stages and kept in an orderly manner in a dry and protected place."
See: 2, below.

The following pictures of used grinding stones came from vintage CM Block grinders. They appear to be original, and probably 4 decades old.

6" dia. 1/3-HP Block grinder m-397.19580 | Note the rust rings.

Same as above, plus 8" dia. 1-HP Block m-397.19360 | Note evidence of grinding on the sides of the stones, which they are not designed for.

Note evidence of non-ferrous metal (aluminum) embedded in the 8" stones. This can result in stone failure when ferrous metal is ground without proper dressing of the wheel.

It's a shame to destroy vintage tools, but these are consumables and not worth the risk. IMO

Use aluminum oxide wheels for all types of steels.

Use silicon carbide green wheels for tungsten cabide and non-ferrous metals such as brass, bronze and aluminum.

Thanks for reading.

For more grinder related links and resources, follow the link below and see post #1.
http://www.garagejournal.com/forum/showthread.php?t=249539
=======================================
Additional information/links

1 Link for one of the many YouTube videos on 'Ring Testing' a grinding stone. --> http://www.youtube.com/watch?feature=player_embedded&v=NDtL4gisZYo

2 A Google search for "vitrified grinding stones and moisture" produced several links, one of which is below.
Grinding and Polishing - Encyclopaedia of Occupational Health and Safety.
http://www.iloencyclopaedia.org/par...sing-and-metal-working/grinding-and-polishing

The Cobbler · Mar 28, 2017

Thanks for sharing . points I had not considered

Carla · Mar 28, 2017

If I may, I'll add a couple more details about using grinding wheels safely, particularly as used on the common varieties of small (12" wheels, and smaller) bench and pedestal grinders.

Don't take the risks involved in trying to save $ with 'brand X' wheels.....some may be intrinsically unsound, and 'blow' with no apparent cause after some time in service.

Do take the time to dress the wheel(s) frequently, preferably with a 'multiple-diamond' type of dresser. Its too easy to get a wheel out of round with the old star-wheel type, unless one is ever so careful.

Do take the time to re-set the tool-rests on a grinder, after dressing the wheel, and set for nearly nil clearance, say .010-ish or so, just clear of the wheel. Its too easy for an unskilled worker or helper to 'catch' a tool in any gap between the rest and the wheel, which may blow the wheel.

edited, another detail to remember.... its always good practice when placing a new wheel on a grinder.... even if you know the grinder to be a good one, and you know the wheel to be a new one of best quality, which has been handled carefully......to start the grinder by standing to one side as you press the start button, and then stay out of line with the wheels, as the grinder runs for 10-15 minutes, before dressing the wheel.

It may be ever so unlikely, but even a best quality new wheel may have a hidden unsound characteristic, such as a crack too small to see, from mis-handling at some point between the manufacturer and the end-user.

cheers

Carla

Zeke · Mar 28, 2017

I'd like to add to your very informative thread that the paper gaskets are a must when installing a wheel on your grinder. They must be in good condition or you need to make some from heavy paper. Tightening the nut on an unprotected wheel can make what was a good stone junk with a crack.

senlow · Mar 28, 2017

^^^^
Words of wisdom.

Grandpa's tools · Mar 28, 2017

Thanks to all for the good information. I bought a block grinder last summer, and replaced both the stone and the wire wheel. The stone I took off had a Craftsman label with the crown logo. It will never be used again, but as an old Craftsman fan, I don't think I want to take a hammer to it. I have some old farm/ tool stuff as part of my "decor", so I may try to figure out some way to show it off in the house. Weird, huh? Ha ha!

M_George · Mar 28, 2017

I know of Norton, what are some other good wheels.

M_George · Mar 28, 2017

Granpa, You might be able to preserve the label and mount it on a wooden mock-up wheel painted with spray paint designed to look like stone.

Roberts210 · Mar 28, 2017

Good points all. Also, the larger diameter the wheel, the greater centrifugal force trying to tear it apart.

torqueman2002 · Mar 28, 2017

M_George said:
Granpa, You might be able to preserve the label and mount it on a wooden mock-up wheel painted with spray paint designed to look like stone.

You noticed that I save one of the 8", as a memento. :lol_hitti

I like your idea. :beer:

slip knot · Mar 28, 2017

So at what point do you determine a wheel is bad? I've got a white Norton wheel that may be 30 yrs old? I only use it to sharpen drill bits so it doesn't get used much. I bought it new and seem to remember it was damned expensive then. I cant see replacing it just because its old.

Dr Stan · Mar 29, 2017

Excellent advise on grinding wheel "care & feeding". I've seen way too many poorly maintained wheels that were accidents just waiting to happen. Ringing a grinding wheel is one of the most ignored safety steps in many shops. Don't assume that a new wheel is OK. Ever seen UPS or FED EX toss packages around?

BTW, this is my favorite dresser: https://www.mscdirect.com/product/details/00127332 as it not only dresses the wheel, but also trues it for much better grinding. Pricey for a dresser, but IMHO well worth the investment.

No direct or indirect connection with MSC, not even a stockholder.

torqueman2002 · Mar 29, 2017

slip knot said:
So at what point do you determine a wheel is bad? I've got a white Norton wheel that may be 30 yrs old? I only use it to sharpen drill bits so it doesn't get used much. I bought it new and seem to remember it was damned expensive then. I cant see replacing it just because its old.

I don't believe a grinding wheel's age is a condition for replacement, in-and-of-it's-self.

I should probably research that, also. I have a grinder that I purchased in the 80's with the OEM stones. See UPDATE, below.

I am positive that there are vintage and used stones out there that are fine and safe to use.

When I see evidence of rust, and general signs of improper grinding stone use, the pucker factor takes over.

I choose an over abundance of caution. New, good stones for my uses are inexpensive.

My intent is to bring the topic to the attention of those who might not be aware of the possible issue.

For more information.
Encyclopaedia of Occupational Health and Safety
Grinding and Polishing
http://www.iloencyclopaedia.org/par...sing-and-metal-working/grinding-and-polishing

UPDATE - April 6, 2017
I contacted Norton (Saint-Gobian) customer service today, Tel: 254-918-2313.

The representative, confirmed that a properly store/used vitrified grinding stone does not have a shelf life.

The key is the stones must have been in a cool & dry environment and pass a ring test.

This is not the same for rosin based grinding stones; they do have a shelf-life. I do not have/use rosin base stones. I do not have any information about them to share.

Tonellin · Mar 29, 2017

Good thread - the moisture aspect is something I never considered. I have a few block grinders and did nothing more than the ring test to determine if I should keep running the 50+ year old stone. I'll look at them against for rust rings and see if the paper is damaged. I can't imagine the paper helps that much against tightening the stone too much?

torqueman2002 · Mar 29, 2017

Dr Stan said:
Excellent advise on grinding wheel "care & feeding". I've seen way too many poorly maintained wheels that were accidents just waiting to happen. Ringing a grinding wheel is one of the most ignored safety steps in many shops. Don't assume that a new wheel is OK. Ever seen UPS or FED EX toss packages around?

BTW, this is my favorite dresser:deleted as it not only dresses the wheel, but also trues it for much better grinding. Pricey for a dresser, but IMHO well worth the investment.

No direct or indirect connection with MSC, not even a stockholder.

Dr - is this the dresser?

MSC - #00127332 | Desmond - 1/2 Carat Single Point Diamond Dresser

I ask because when I followed the link above, my security program flagged the site for '... malware or exploits.'

torqueman2002 · Mar 29, 2017

Tonellin said:
Good thread .... I can't imagine the paper helps that much against tightening the stone too much?

Thank you.

Well, I am learning a lot about these 'every-man's' tools, found in most home garages/workshops.

"These blotters are more than just cardboard or paper, but are designed to strict standards for material type, thickness, coefficient of friction, and compressibility. Do not attempt to create your own by cutting blotters from old paper cartons, sheets of rubber, or leather, etc. Use only blotters that are supplied or recommended by the abrasive wheel manufacturer."

From: Blotters... What Good Are They?
http://magna-matic.com/pdf/norton/Safety - Blotters - What Good Are They.pdf

:thumbup:

Tonellin · Mar 29, 2017

torqueman2002 said:
Thank you.

Well, I am learning a lot about these 'every-man's' tools, found in most home garages/workshops.

"These blotters are more than just cardboard or paper, but are designed to strict standards for material type, thickness, coefficient of friction, and compressibility. Do not attempt to create your own by cutting blotters from old paper cartons, sheets of rubber, or leather, etc. Use only blotters that are supplied or recommended by the abrasive wheel manufacturer."

From: Blotters... What Good Are They?
http://magna-matic.com/pdf/norton/Safety - Blotters - What Good Are They.pdf

wow no kidding...very informative thank you

twertsy · Mar 29, 2017

I picked this up this weekend for $15. I love the old Thor stuff. Trust me, the wheel will be replaced before using! Hell, I was amazed it even had the guard.

Zeke · Mar 29, 2017

torqueman2002 said:
Thank you.

Well, I am learning a lot about these 'every-man's' tools, found in most home garages/workshops.

"These blotters are more than just cardboard or paper, but are designed to strict standards for material type, thickness, coefficient of friction, and compressibility. Do not attempt to create your own by cutting blotters from old paper cartons, sheets of rubber, or leather, etc. Use only blotters that are supplied or recommended by the abrasive wheel manufacturer."

From: Blotters... What Good Are They?
http://magna-matic.com/pdf/norton/Safety - Blotters - What Good Are They.pdf

I'm not going to run out of my shop screaming just because I don't have 'engineered' wheel "blotters." What I use is fine for me but thanks for warning the proletariat that these standards do exist. At least we are preventing some from mounting their grinding wheels w/o the cushion.

nine4gmc · Mar 29, 2017

Good stuff Torqueman!

torqueman2002 · Mar 29, 2017

Zeke said:
I'm not going to run out of my shop screaming ....

That's funny. :lol:

rmalkow2 · Mar 30, 2017

Very good info and food for thought. You got me convinced that it's much easier and safer to just replace unknown wheels than take the chance.
I've ended up with many older grinding wheels as part of some lot at an auction or sale and they always get destroyed and tossed. I just can't trust them without knowing the history myself.

pendragon1998 · Mar 30, 2017

I don't use old grinding wheels either. It's just not worth the risk.

vettex2 · Mar 30, 2017

The Cobbler said:
Thanks for sharing . points I had not considered

Same here.

SweetD · Mar 30, 2017

torqueman, please recommend decent grinding wheels/stones for the C-Man block grinders. I have a few I need to replace.

Thanks!
Dave

M_George · Mar 30, 2017

I hear Norton wheels being recommended often. But these are not always available and can be pricey. Is there any other quality manufactures out there?

pendragon1998 · Mar 30, 2017

I like CGW (Camel Grinding Wheels), made in Israel. I buy the 7"x1" wheels on ebay. I have a blue and a white wheel on mine

rsanter · Mar 30, 2017

The only issue I see is that if someone wanted to 'restore' one of them to all original you are destroying original equipment.
If I was worried about that I would save the paper sides that are in good shape as they could be applied to new wheels to make them appear to be correct original pieces.

Now I'm saying this from the point of a car restorer....may not apply to tools, but with as popular as the block grinders are....

Bob

cybrdyke · Mar 30, 2017

I would destroy mine, but they're 4" diameter and they're really really really hard to find.
Anyone have any suggestions?
CD

Pig9r · Mar 30, 2017

I am having trouble finding 7" wheels. Zoro has them but after ordering I got notice they are out of stock. No luck at any of the usual interweb places either. I am not feeling good about using these. Any suggestions appreciated.

454ragtop · Mar 31, 2017

Pig9r said:
I am having trouble finding 7" wheels. Zoro has them but after ordering I got notice they are out of stock. No luck at any of the usual interweb places either. I am not feeling good about using these. Any suggestions appreciated.

I'd probably use the one on the right, after careful inspection and stand off to the side when starting. That one on the left is badly abused, last guy was lucky it didn't break on him, that type of wheel is NOT made to use the side of the wheel.

torqueman2002 · Apr 1, 2017

Hi, sorry I didn't notice these question before. Sometimes the new posts don't appear when I click the button.
I'll reply in Red.

M_George said:
I know of Norton, what are some other good wheels.
Here's a link to a post with 3 sources, also Camel is mentioned below.
http://www.garagejournal.com/forum/showpost.php?p=5303162&postcount=7364

slip knot said:
So at what point do you determine a wheel is bad? I've got a white Norton wheel that may be 30 yrs old? I only use it to sharpen drill bits so it doesn't get used much. I bought it new and seem to remember it was damned expensive then. I cant see replacing it just because its old.
I am wondering that myself, now. I eMailed Norton, and will report back with any updates.

SweetD said:
torqueman, please recommend decent grinding wheels/stones for the C-Man block grinders. I have a few I need to replace.
Please see the 3 links above.
Thanks!
Dave

M_George said:
I hear Norton wheels being recommended often. But these are not always available and can be pricey. Is there any other quality manufactures out there?
Please see the 3 links above.

pendragon1998 said:
I like CGW (Camel Grinding Wheels), made in Israel. I buy the 7"x1" wheels on ebay. I have a blue and a white wheel on mine

cybrdyke said:
I would destroy mine, but they're 4" diameter and they're really really really hard to find.
Anyone have any suggestions?
CD
Sorry, I don't know for sure. Please see the 3 links above.

Pig9r said:
I am having trouble finding 7" wheels. Zoro has them but after ordering I got notice they are out of stock. No luck at any of the usual interweb places either. I am not feeling good about using these. Any suggestions appreciated.
IIRC - I have found 7" at MSCDirect. Please see the 3 links above.

One note, some stones need arbor adapters to fit Block 5/8" & 1/2" dia. arbors.

pendragon1998 · Apr 1, 2017

torqueman2002 said:
One note, some stones need arbor adapters to fit Block 5/8" & 1/2" dia. arbors.

The Camel (CGW) wheels I mentioned come with a plastic telescoping / nested-style adaptor for various arbor sizes, fyi.

ecotec · Apr 1, 2017

Torqueman, ever buy grinding wheels from Production Tool?

r_olson_06 · Apr 1, 2017

Picked this gem up today with the stand. Still AHS the original paperwork. $45

Sent from my XT1080 using Tapatalk

Carla · Apr 1, 2017

cybrdyke said:
I would destroy mine, but they're 4" diameter and they're really really really hard to find.
Anyone have any suggestions?
CD

Any wheel may be made to blow, if, for example, a tool is wedged between the wheel and tool rest, when the wheel is running.

That said, a 4" diameter wheel of any good make is ever so unlikely to blow, if kept trued/dressed, and run at or below its rated speed, as it has so very little welght/mass to become unbalanced.

In short, I'd not feel badly about running old 4" wheels, were they mine.

cheers

Carla

torqueman2002 · Apr 1, 2017

ecotec said:
Torqueman, ever buy grinding wheels from Production Tool?

No. I should check them out, they have a branch close to me.

:thumbup:

They have a number of bench/pedestal grinder stones.
http://www.pts-tools.com/cgi/CGP2LMXE

cybrdyke · Apr 1, 2017

Carla said:
That said, a 4" diameter wheel of any good make is ever so unlikely to blow, if kept trued/dressed, and run at or below its rated speed, as it has so very little welght/mass to become unbalanced.

In short, I'd not feel badly about running old 4" wheels, were they mine.

cheers

Carla

That's really good to know. Thank you!

torqueman2002 said:
Hi, sorry I didn't notice these question before. Sometimes the new posts don't appear when I click the button.
I'll reply in Red

Sorry, I don't know for sure. Please see the 3 links above.

Thank you, Torqueman. I followed the links and ordered new wheels from MSC.

CD

torqueman2002 · Apr 1, 2017

cybrdyke said:
That's really good to know. Thank you!

Thank you, Torqueman. I followed the links and ordered new wheels from MSC.

CD

Glad you found what you needed.
:thumbup:

torqueman2002 · Apr 7, 2017

I continued the tear-down of a 1/3-HP Block today. I actually debated if it needed to be left as-found and offered up as-is.

CM%200.33%20HP%20397.19580%20115V%20Howell%200984.jpg

CM%200.33%20HP%20397.19580%20115V%20Howell%200985.jpg

CM%200.33%20HP%20397.19580%20115V%20Howell%200982.jpg

I think it shows well for just a dust off and wipe down with window cleaner.

When I removed the arbor/shaft I was surprised by the rust on the rotor body. The rust on outer RH end of arbor didn't give me pause; that is some what common.

CM%200.33%20HP%20397.19580%20115V%20Howell%200048.jpg

Maybe the reddish color at the inside of the bearing is not old grease.

CM%200.33%20HP%20397.19580%20115V%20Howell%200049.jpg

LH bearing/arbor.

CM%200.33%20HP%20397.19580%20115V%20Howell%200050.jpg

Close up of field coil. Rust is evident on outer edge of core-laminations.

CM%200.33%20HP%20397.19580%20115V%20Howell%200051.jpg

This is the same 1/3-HP Block grinder m-397.19580 that these stones & flanges came from, in post #1 above.

CM%200.33%20HP%20397.19580%20115V%20Howell%200995.jpg

So, at the risk of beating this dead horse :deadhorse

a little more, I believe replacing used stones of unknown history is prudent.

Thanks for reading and for your posts.

:thumbup:

Old grinding stones

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