Bench Grinder For Grinding Lathe Tools: Advice Needed

[Nogoingback]

I don't use CBN wheels but @Dan_S does. Maybe he'll chime in here.

Hopefully he will. If not, I can always PM him. Thanks for the contact info though.

 

[Uglydog]

What's the Free Box?

When you ring a wheel, are you just tapping it and making sure it doesn't "clunk" due to a crack or imperfection?

Sometimes rummage and estate sale operators/families will put low value items or stuff they don't expect to sell in a box labeled "Free".
Oftentimes it's at the end of the driveway.

Check out ringing: http://newmetalworker.com/Howto/ringtstwhls.html
I won't buy a new wheel if they won't let me check it.

Daryl
MN

 

[Charles Spencer]

Charles, with 3 bench grinders to choose from, do you have one you use the most?, and if
so, why?

Well for years I used an old refrigerator motor with an arbor and a grinding wheel mounted on the spindle to sharpen chisels, yard tools, etc. but I don't anymore.

Then I got the 8" bench grinder from Harbor Freight with the goose neck lamp. That worked fine after I replaced the horrible excuse for a tool rest they had:

http://www.harborfreight.com/8-inch-bench-grinder-with-gooseneck-lamp-37823.html

I got a deal on a 6" DeWalt that was made in China. No better than the HF one except for the tool rests. This is the one I mostly use now simply for space savings:

https://www.lowes.com/pd/DEWALT-6-in-Bench-Grinder/3557688

Then I found an old Dunlap at a flea market for $5.00. The grease was hardened on the bearings but it ran well after I cleaned and re-greased them:

And I finish grinding on an HF mini grinder:

http://www.harborfreight.com/3-inch-mini-tool-grinder-polisher-94071.html


A grinder is not a complicated mechanism. To my mind, the wheel is the critical element. I try to use Norton wheels exclusively because I am sure of their quality and they come from my hometown. Do the ring test as suggested above and make sure you dress it carefully and you should be good to go.

You don't need to spend lots of dollars to have a good time and do good work.

Amen.

 

[Dave Paine]

Wood workers call the 1800 rpm grinders "slow speed". Many grinders operate at 3600 rpm.

If you can wait for a few months, Woodcraft have the Rikon 1/2HP 8in slow speed grinder on sale for $99.99. Goes on sale a few times a year.

https://www.woodcraft.com/products/rikon-8in-slow-speed-grinder

Not the best grinder. The wheels may wobble. Mine did, same for two local friends who have the same. Wobble is due to the inside washer not having enough of a shoulder to register flat on the shaft so it partially rides up the small shoulder causing the wobble.

The CBN wheels are nice. I have not yet purchased, but will eventually. These wheels are balanced steel with the CBN coating. This means they are heavier than normal abrasive wheels. It will take some time to get to speed on a 1/2HP grinder. Bigger HP is preferred. Also will take a lot longer to spin down.

The WoodturnersWonder link Mikey has is a good site for CBN wheels. You can get sharp corner wheels or radius corner wheels with some CBN on the side. Good for certain grind shapes.

 

[f350ca]

I wouldn't recommend a slow speed grinder for high speed steel. Wood workers (myself included) deal with high carbon steel hand chisels and hand plane blades. They won't tolerate heat, high speed steel doesn't care. HSS can get red hot and not affect the hardness, thats why we use it.
Just about any 1/2 HP 3400 rpm grinder will work, 6 inch wheels are fine but 7 or 8 are faster cutting as the surface speed is higher. A little hollow grind from the radius of the wheel aids in honing the final edge on a hand stone.
If you get an import grinder throw the stones away, they are little more than circular concrete disks. Get good quality ones. The white aluminum oxide ones are indispensable in the wood working shop, they cut cool but at a price, they fragment to stay sharpe and as a result wear fast, you don't need them for HSS.

Greg

 

[Charles Spencer]

Dave makes a good point. But you have a lathe. Therefore you can make better washers (flanges) to use.

Also, I cut circles out of 3x5 index cards to place between the washer and the stone. I think this helps stabilize the wheel and reduce vibration.

 

[Nogoingback]

Sometimes rummage and estate sale operators/families will put low value items or stuff they don't expect to sell in a box labeled "Free".
Oftentimes it's at the end of the driveway.

Check out ringing: http://newmetalworker.com/Howto/ringtstwhls.html
I won't buy a new wheel if they won't let me check it.

Daryl
MN

OK, I get it. For some reason I thought you were talking about something on the forum.

Thanks for the video. Exactly what I needed. I knew people did ring tests, but didn't know how.

 

[Nogoingback]

Well for years I used an old refrigerator motor with an arbor and a grinding wheel mounted on the spindle to sharpen chisels, yard tools, etc. but I don't anymore.

Then I got the 8" bench grinder from Harbor Freight with the goose neck lamp. That worked fine after I replaced the horrible excuse for a tool rest they had:

http://www.harborfreight.com/8-inch-bench-grinder-with-gooseneck-lamp-37823.html

I got a deal on a 6" DeWalt that was made in China. No better than the HF one except for the tool rests. This is the one I mostly use now simply for space savings:

https://www.lowes.com/pd/DEWALT-6-in-Bench-Grinder/3557688

Then I found an old Dunlap at a flea market for $5.00. The grease was hardened on the bearings but it ran well after I cleaned and re-greased them:

View attachment 230083

And I finish grinding on an HF mini grinder:

http://www.harborfreight.com/3-inch-mini-tool-grinder-polisher-94071.html


A grinder is not a complicated mechanism. To my mind, the wheel is the critical element. I try to use Norton wheels exclusively because I am sure of their quality and they come from my hometown. Do the ring test as suggested above and make sure you dress it carefully and you should be good to go.



Amen.

Dave makes a good point. But you have a lathe. Therefore you can make better washers to use.

Also, I cut circles out of 3x5 index cards to place between the washer and the stone. I think this helps stabilize the wheel and reduce vibration.

Good information Charles, thank you. I'll stick with Norton when the time comes. I also like your tip on the index cards.

 

[Dabbler]

A quick word on grinding and grinding wheels. As a part of shop practice, I never stand in the plane of rotation of a grinding wheel, Not at start up, not during use. If I have to cross the plane, I don't linger. In my 50 years doing grinding, I have seen a wheel explode on someone else, at a high school shop, and one in my own shop. For the one in my owns shop, it was always lightly used, never suffered any damage of any kind. It just went one day. Scared the daylights out of me, but I did not get injured. It was a 6" fine grain AO wheel. I figure there was a slight manufacturing defect that finally let go.

 

[Nogoingback]

Wood workers call the 1800 rpm grinders "slow speed". Many grinders operate at 3600 rpm.

If you can wait for a few months, Woodcraft have the Rikon 1/2HP 8in slow speed grinder on sale for $99.99. Goes on sale a few times a year.

https://www.woodcraft.com/products/rikon-8in-slow-speed-grinder

Not the best grinder. The wheels may wobble. Mine did, same for two local friends who have the same. Wobble is due to the inside washer not having enough of a shoulder to register flat on the shaft so it partially rides up the small shoulder causing the wobble.

View attachment 230086

The CBN wheels are nice. I have not yet purchased, but will eventually. These wheels are balanced steel with the CBN coating. This means they are heavier than normal abrasive wheels. It will take some time to get to speed on a 1/2HP grinder. Bigger HP is preferred. Also will take a lot longer to spin down.

The WoodturnersWonder link Mikey has is a good site for CBN wheels. You can get sharp corner wheels or radius corner wheels with some CBN on the side. Good for certain grind shapes.

Thanks Dave. I'll keep an eye out on the Woodcraft site. The weight of the CBN wheels explains why Woodcraft has a video comparing the wheels on two different grinders: I was wondering
why. They look like good wheels.