# Bench Grinder For Grinding Lathe Tools: Advice Needed



## Nogoingback (Mar 29, 2017)

I'm thinking  about learning to grind my own lathe tools and need a  bench grinder
to do it with. (Up to this point I've been using HSS insert type tooling.)

 Baldor's are probably out of my budget, but a decent
older USA made machine is what I have in mind.  Is there a minimum HP I should look for, and 
what motor RPM is best? (Or are they all the same?).   What 
grinding wheel diameter would be best in terms of performance, availability and cost?  Any particular 
brands or models? Any other considerations?


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## Charles Spencer (Mar 29, 2017)

Virtually any bench grinder should be able to grind HSS bits.

I have three bench grinders and two stationary sanders.  I usually rough out bits on one of the bench grinders, but I finish on a Harbor Freight mini tool grinder.


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## mikey (Mar 29, 2017)

Nogoingback said:


> I'm thinking  about learning to grind my own lathe tools and need a  bench grinder
> to do it with. (Up to this point I've been using HSS insert type tooling.)
> 
> Baldor's are probably out of my budget, but a decent
> ...



I suggest at least 3/4 to 1 HP if you can. Grinding on a wheel requires pressure and you will bog down a weak motor. Most grinders will run in the 1800 rpm range, although there are slow speed grinders as well. 

As for wheel size, I would go for an 8". Wheels are common and there is less of a curvature to the grind so your edges last longer. If I were you, I would definitely consider a CBN wheel for tool grinding - something coarse in the 60-80 grit range. A slight radius on the corner of the with a CBN wheel on one end and maybe a fine finishing AO wheel on the other or a fine CBN wheel if I could afford it. Check this guy out: https://woodturnerswonders.com/collections/rikon-grinders

A grinder as above is for tool grinding only. I don't think I would use a CBN wheel for everyday grinding.

I use a belt sander.


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## Doubleeboy (Mar 29, 2017)

You can rough grind using a cheap angle grinder like one from HF for cheap and then finish on a small grinder.  I have two  Taiwan 8" grinders, plus a 1" belt plus my angle grinders.  When I want to rough a large bit, I take the angle grinder outside clamp the bit to wood bench and go to town with angle grinder, very fast way to rough IMO.


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## Nogoingback (Mar 29, 2017)

OK, good useful information.  It sounds like an 8" is the way to go, and I'll make sure I don't go too low on power.  I already have an  angle grinder and a 1" belt sander so I suppose
I could rough out with those, but in the long run I'd rather have the right wheels to do it all on one dedicated machine.   Then, I can use the other machines for everyday grinding tasks.  mikey,
thanks for the info on CBN wheels:  they look expensive but if they last a long time and don't need dressing I imagine I could stretch for one of them.  I haven't priced out regular wheels,
 so I don't know how they compare.  While we're on the subject of grinding wheels, who makes good ones, or does it matter?  (I know, it almost always matters...)

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


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## Uglydog (Mar 29, 2017)

Old arbor grinders are cheap if not free! Bushings or bearings can be replaced easily.
If it doesn't have a guard and rest you can make one easy enough.
Any motor will work.
You don't need to spend lots of dollars to have a good time and do good work.

Daryl
MN


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## Nogoingback (Mar 29, 2017)

Uglydog said:


> Old arbor grinders are cheap if not free! Bushings or bearings can be replaced easily.
> If it doesn't have a guard and rest you can make one easy enough.
> Any motor will work.
> You don't need to spend lots of dollars to have a good time and do good work.
> ...




That's kind of the conclusion I've drawn from trolling CL.  Around here older USA or USA branded Taiwan machines usually run between $50.00 to $100.00 if they're
decent. Right now the closest  to what I'd like is a Taiwanese Dayton 1/2 hp with 7" wheels for $60.00.  I'm not in a hurry to buy one, so I can afford to take my time and look
for a bargin.


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## Uglydog (Mar 29, 2017)

If you are willing to pay shipping and supply a motor and new bushings I'll send you a grinder arbor/stand free.
However, you might be better off waiting for rummage/estate sales.
These sort of machines show up in the Free Box, or you can negotiate to nearly free.

Be careful of used grinding wheels. Learn how to "ring" them, and stand back on start up!

Daryl
MN


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## mikey (Mar 29, 2017)

Nogoingback said:


> mikey,
> thanks for the info on CBN wheels:  they look expensive but if they last a long time and don't need dressing I imagine I could stretch for one of them.  I haven't priced out regular wheels,
> so I don't know how they compare.  While we're on the subject of grinding wheels, who makes good ones, or does it matter?  (I know, it almost always matters...)



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


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## Nogoingback (Mar 29, 2017)

Uglydog said:


> If you are willing to pay shipping and supply a motor and new bushings I'll send you a grinder arbor/stand free.
> However, you might be better off waiting for rummage/estate sales.
> These sort of machines show up in the Free Box, or you can negotiate to nearly free.
> 
> ...



Thanks for the offer Daryl, but I might just wait for something local.  The shipping and a 
motor could add up to just as much as buying the complete machine.

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?


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## Nogoingback (Mar 29, 2017)

mikey said:


> 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.


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## Uglydog (Mar 30, 2017)

Nogoingback said:


> 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


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## Charles Spencer (Mar 30, 2017)

Nogoingback said:


> 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.



Uglydog said:


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



Amen.


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## Dave Paine (Mar 30, 2017)

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.


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## f350ca (Mar 30, 2017)

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


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## Charles Spencer (Mar 30, 2017)

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.


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## Nogoingback (Mar 30, 2017)

Uglydog said:


> 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
> ...



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.


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## Nogoingback (Mar 30, 2017)

Charles Spencer said:


> 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:
> 
> ...





Charles Spencer said:


> 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.


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## Dabbler (Mar 30, 2017)

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.


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## Nogoingback (Mar 30, 2017)

Dave Paine said:


> 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.
> 
> ...



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.


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## Nogoingback (Mar 30, 2017)

f350ca said:


> 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



Greg, I'm glad you clarified high speed vs. low speed grinders for me, as well as your comments on stones.  You guys are giving me a great education on grinders, which was EXACTLY what I was
looking for when I posted this thread.


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## Nogoingback (Mar 30, 2017)

Dabbler said:


> 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.



Dabbler, thanks for the safety reminder.  I'll keep it in mind for the day that I feel too lazy to go get the face shield...


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