Sharpening lathe tools with a grinder

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Forum topic by lumberjoe posted 08-10-2012 08:41 PM 7525 views 1 time favorited 18 replies Add to Favorites Watch
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2899 posts in 2248 days

08-10-2012 08:41 PM

I plan on making a jig similar to the wolverine to sharpen my lathe tools. How important is a slow speed grinder? I rarely see any for sale, and the ones I do see aren’t much less than just getting Tormek T3.

Also, could I use a potentiometer to make a standard grinder “variable speed”?


18 replies so far

View Arlin Eastman's profile

Arlin Eastman

4217 posts in 2560 days

#1 posted 08-10-2012 08:51 PM


It only matters of you are not using highspeed steel like M2. I have ground regular steel using highspeed grinder, however, you have to use a light touch and I also use a Qtip with water to keep the steel cooler. I have a highspeed(3500rpm) a slowspeed(1750), a tormack and stones and diamond.
For turning I hone 90% of the time then when the angle changes to much I do a quick grind.


-- It is always the right time, to do the right thing.

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2899 posts in 2248 days

#2 posted 08-10-2012 08:55 PM

The tools I have are all HSS


View TheDane's profile


5423 posts in 3662 days

#3 posted 08-10-2012 10:13 PM

lumberjoe—WoodCraft has a 1725rpm grinder that sells for about $125 … I have one and am perfectly happy with it.

With HSS tools, you can use a regualr (3450rpm) grinder, but it is easy to grind off a lot more steel than necessary. Once you get the grind/bevel you want, routine sharpening should only take tiny amounts of steel off the tool.


-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View lumberjoe's profile


2899 posts in 2248 days

#4 posted 08-11-2012 01:59 AM

Picked up a cheapo harbor freight 8” grinder. I ran it in the store to make sure it wouldn’t dance all over my shop. I often ask to test stuff at HF before I buy it and they are always cool with it. It took me 3 tries, but I got one that runs true. I made my own little table and “wolverine” style jig. While I was at HF I bought some cheap HSS turining tools so I could practice sharpening. I marked them with a sharpie and set my jig. Got it right on the first shot! I sharpened the 1” gouge and tried it out. It cut waaay better than a gouge that cost me twice as much as the set of 8 tools I just bought to practice sharpening on!

I then took the 3/4” gouge right out of the HF box and took it to the lathe. Pathetic. I really had to work to make chips. I took it to the grinder, made 2 passes, then took it to the wood again. Chips were flying over my head as soon as the gouge kissed the wood (hard maple). I sharpened up the rest of my gouges and shut the lights out.

That monkey is off my back for now. What did people do before the internet?

Also as a side note, That Windsor design 8 piece HSS lathe tool set from HF seems pretty decent. I bought it with the intention of ruining them on a grinder while I figured out how to sharpen. Now that they are sharp, I’m wondering why I spent so much money on gouges. I guess time will tell.

Next turning project – tool handles for the cheapos! The ones on there are actually nice, I just don’t like the ergonomics.


View MrRon's profile


4770 posts in 3243 days

#5 posted 08-11-2012 07:28 AM

You cannot vary the speed of a bench grinder that has a syncronous motor.

View Wildwood's profile


2306 posts in 2134 days

#6 posted 08-11-2012 04:56 PM

Do not know how to make a grinder variable speed.

Have been using a Sears 6” x 3/4 “ 4350 1/3 hp bench grinder for almost 20 years to sharpen my tools. Made couple of different sharpening jigs, broke down a bought down and bought a Wolverine set up soon after buying my grinder.

JMHO, high-low speed grinder not important both will blue your tools if not using a light touch. If had a variable speed grinder would keep it on fastest setting. Size of a bench grinding wheels not important to me. Do wish had a 1” wide wheel on my bench grinder.

I am not impressed with 8” grinders with ¾” wide wheels or less than ¾ hp. Many brands advertize number of amps vice horsepower. Doing little a math shows many brands less than ¾ HP.

Since majority of bench grinders sold here made in China price not always an indication of quality. So say buy locally so can exchange or get money back if stuck with a lemon.

-- Bill

View A10GAC's profile


191 posts in 3077 days

#7 posted 08-11-2012 05:32 PM

I read this post a few days ago about a member who was using a dimmer switch to control the speed on his grinder. No idea what this would do to the tool motor, but, seems like it would be inexpensive enough to try if you wanted.

-- Men have become the tools of their tools. - Henry David Thoreau

View Dusty56's profile


11819 posts in 3687 days

#8 posted 08-11-2012 05:55 PM

I bought a Wolverine jig and a Variable Speed Delta grinder off of Craigslist. Haven’t had a chance to set them up yet though.
Glad your homemade jig came out well for you , Joe : )

-- I'm absolutely positive that I couldn't be more uncertain!

View a1Jim's profile


117091 posts in 3576 days

#9 posted 08-11-2012 06:25 PM

I don’t see the point of a low speed grinder ,all you have to do is make sure you cool you lathe tools cool by dipping in water if you have to grind a lot off so your tools don’t loose your temper. I’ve made a wooden jig like your talking about and it works great on my old high speed grinder. Mine is similar to this one.

-- wood crafting & woodworking classes

View lumberjoe's profile


2899 posts in 2248 days

#10 posted 08-13-2012 12:28 PM

I use the q-tip trick to keep them cool. I wet a q-tip and place the end of it just below the tip of the gouge. I hold it there with my thumb, then grind away. It keeps the tool nice and cool. I cannot believe what a difference sharp tools make while turning. This is also one of the easiest and most effective jigs I have made. Now, to figure out how to sharpen skews, parting tools, and the round nose scraper.


View TheDane's profile


5423 posts in 3662 days

#11 posted 08-13-2012 12:59 PM

One of the guys in my turning club is a metalurgist … he advises against dipping HSS tools in water (‘quenching’) to cool them. He says it can cause micro-cracks, resulting in chipping and cracking.

An 8” slow speed grinder with a 46 grit Norton wheel can take a lot of steel off without generating much heat. My WoodCraft grinder has a 46 grit wheel for grinding a new bevel and an 80 grit for touching up a working edge.

@lumberjoe—Do you have a tool rest for your grinder? To sharpen scrapers, skews, and parting tools, all you really need is a tool rest that has an adjustable platform. If you don’t have one, Grizzly has one (G8987 Optional Heavy-Duty Tool Rest) for about $20.


-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View Terry Vaughan's profile

Terry Vaughan

40 posts in 2156 days

#12 posted 08-13-2012 02:17 PM

One of the most important things is to keep the grinding wheel clean. Specks of metal stuck on the wheel come round and can hammer the edge off the gouge as fast as you sharpen it. The diamond blocks in a handle are a real boon. If you keep them clean, even the gray wheels work well.

-- Terry,

View lumberjoe's profile


2899 posts in 2248 days

#13 posted 08-13-2012 04:27 PM

The grinder does have tool rests. I’ll give that a shot


View hairy's profile


2703 posts in 3531 days

#14 posted 08-13-2012 04:47 PM

Take a look at what CapnEddie has to offer.

He’s a lumberjock,too. He has a boatload of videos, such as:

-- My reality check bounced...

View TheDane's profile


5423 posts in 3662 days

#15 posted 08-13-2012 11:31 PM

@lumberjoe—The little dinky tool rests that most grinders come with won’t help much … you need one with a pretty good-sized platform like the Grizzly or the ones that OneWay provides with the Wolverine system.


-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

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