How to balance grinding wheels

[ringwood]

I am a beginning woodturner and recently purchased a slow speed grinder from Woodcraft and the Wolverine sharpening system. Over the weekend I had a little mishap when sharpening. My tool accidentally slid off of the wheel and got lodged between the wheel and the bottom of the grinder. The wheel isn't cracked but the sides were dinged up a bit. But the main problem is that the wheels are now totally out of balance. Can someone give me some pointers on balancing the wheels? I hope I didn't bend the axel! Thanks for any tips.

Kathy

 

[MichaelMouse]

You can confirm axle problems or compressed wheel insert - which is more likely - by checking if the wheels are in constant contact with a touch gage against the side.

You will want to use a wheel dresser to get the chips out of the way, that's for sure. Otherwise a bit of inattention will catch and tip the tool again, especially if you're supporting it far from the wheel.

For balance, consider squashed lead shot in holes in a cardboard washer under the metal one.

 

[Malcolm Smith]

I don't know how 'slow speed' the grinder is but you should be cautioned that a turning stone that breaks or loses a piece can cause serious injury. It has always been the rule that one should stand to the side when turning on a grinder. I would urge you to wear a full face plate. Also, the dust from the stones will remain in your lungs. I wear a respirator when grinding tools.

Malcolm Smith.

 

[waltben]

I've used the same setup for over six years now, but haven't had the opportunity to try out sharpening on the side of a wheel yet ;-). The first thing I'd do would be to take apart the grinder to see if you managed to damage the arbor, motor shaft or something causing the wheels to not rotate in a 90 degree true manner. A wheel dresser will clean and true roundness, but if you've bent the motor shaft (or there's a bushing of some sort that got crushed), then the grinding wheel won't run true right to left while looking at it from the front. I've heard of folks dressing the sides of wheels, but I've never felt that was worth the effort. The most important thing is that the surface you'll be sharpening your tools on is smooth and clean - a wheel can be not balanced (as long as your grinder isn't vibrating) and still give as good an edge as one with an expensive balancing system.

 

[Brian Hahn]

I had a similar incident with a standard grinder a couple of years ago - I was grinding the head on a bolt when it slipped, jammed and went flying. It dinged up the wheel and bent the arbor. The bent arbor was pretty obvious because the wheel wobbled side-to-side. That grinder is now a one-wheel grinder. The wheel was not cracked, so all I needed to do was to dress the wheel to remove the surface damage.

 

[Jred]

The Oneway wheel balancing system is a very nice addition to a grinder even if the wheels haven't had a problem. It makes quite a difference I've found.

 

[KEW]

Take the wheel off of the grinder and put it over a screwdriver shank and give it a good sharp flick. It should make a nice ceramic sounding ring (as a tea cup might). If it gives a dull clank, it is broken - do not use it!

 

[john lucas]

Great advice so far. I would also urge removing the wheel and checking the shaft to see if it runs true. The screwdriver ring test is one that should always be performed before installing a wheel. Even at 1700 rpm and exploding wheel is quite exciting at the least.
After you've checked the arbor and cleaned the washers, reinstall the wheel. Then check to see if it's running true. If it's close the you can use a diamond point tool or a Diamond T tool to true the wheel. I wouldn't worry about the sides.
If the wheel wobbles side to side you can change that by adding small paper or brass shims between the washer and the wheel. Once you get the side to side wobble out you can true up the front surface.

 

[hockenbery]

If the grinder shaft and bushings are ok

1. be sure you have no cracks. As Kew said it should have ring when hit gently. Use this test for a new wheel too!

2. When I mount a new wheel, I mark its location relative to shaft.
If i have vibration when I turn on the grinder, I loosen the nut and rotate the wheel in 15 degree increments.
I repeat this process until there is no or go back to the location that had the least vibration.

3. I then true the wheel with a diamond dresser using very light pressure
so that I remove the high spots and not follow the bumps around the wheel.

 

[Richard Baker]

One more little safety procedure we used to have at work, many moons ago. When installing a new wheel or even reinstalling a used one that was "known" to be round and balanced; on startup if it is balanced well enough to not require immediate shutdown, stand aside (like next to a remote plug or the breaker) and let it run for one full minute. The reasoning and experience behind this rule was of course that if something was going to come seriously unstuck, it would happen within one minute. If nothing untoward occurred after a minute, it was permissable (with safety glasses, face shield, and full body armor) to dress the wheel and press on with life.

Fortunately have never had a wheel bad enough that a little dressing couldn't smooth it out. But I still do the one minute thing.

(Edit: Ignore this paragraph. Already covered by Hock. Skip to next ppg.)Note when dressing a wheel, not unlike making a fine finish cut, support dresser on the tool rest and motor gently. Too much pressure on an oval wheel will just get you a nicely dressed oval wheel. Very light pressure may result in a nicely dressed round wheel.

Very cool balancing idea from MM for those of us who prefer not to buy it if we can make it. Tiny split shot from the fishing department might work.

Yammer, yammer. Sorry about that.

 

[KEW]

Ernie Conover recommends - whenever putting a new wheel on, stand to one side, turn on the grinder, then leave the room for 5 minutes (get a cup of coffee)!

 

[Don Geiger]

Grinder Safety and Balancing Wheels

Any time you suspect you have damaged a grinding wheel you should remove it from the grinder and perform a ring test. This is a test is used to determine the integrity of the wheel. The test is described at: http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9839

As far as balancing the wheels, what works well is to make the wheels concentric to the axle. This may be done using the wheel truing device found at: www.geigerssolutions.com.

After truing the wheels, your tools will ride smoothly on the surface and will not bounce. This will help you concentrate on keeping your tool centered on the wheel. Good luck!

 

[KEW]

Just to save some time hunting, here is OSHA's description:

1910.215(d)(1)

Inspection. Immediately before mounting, all wheels shall be closely inspected and sounded by the user (ring test) to make sure they have not been damaged in transit, storage, or otherwise. The spindle speed of the machine shall be checked before mounting of the wheel to be certain that it does not exceed the maximum operating speed marked on the wheel. Wheels should be tapped gently with a light nonmetallic implement, such as the handle of a screwdriver for light wheels, or a wooden mallet for heavier wheels. If they sound cracked (dead), they shall not be used. This is known as the "Ring Test".

 

[Malcolm Smith]

While grinders come with wheels, they are normally of very poor quality and not very suitable for sharpening the tools we use. There may be exceptions to this but I haven't seen them. I would guess that they are there because something has to be. Spend some time in the catalogues and buy at least one high quality wheel, preferably two. This will make a considerable difference.

Malcolm Smith

 

[Richard Baker]

How does one know what is a good wheel or a poor wheel, especially just from reading the catalog? I have a half dozen wheels in maybe 3 different grits and probably none of them is actually a "good" wheel. How can I tell?

 

[ringwood]

Thanks everyone

Thank you to everyone who responded to my question concerning my grinder mishap. I'll take the wheel off (tonight, perhaps) and be back to report on what I find. This site is a tremendous resource. Thanks to all who support it!

Kathy

 

[Don Geiger]

Grinding wheel selection

For high speed tools: friable Aluminum Oxide wheels, 60 to 120 grit, with a hardness rating of: H, I, J or K are well suited. I use blue 80 grit CGW or Norton. Make sure you know the hardness before you order.

Ring test a new wheel before installing it. Then true the wheel, making sure the circumference is concentric to the axle. If the wheels are properly trued; the vibration of the grinder will be greatly reduced and your tools will not bounce on the surface. This can be accomplished quickly and easily using my truing device and there are some others on the market.


Don Geiger
www.geigerssolutions.com
www.dongeiger.com

How does one know what is a good wheel or a poor wheel, especially just from reading the catalog? I have a half dozen wheels in maybe 3 different grits and probably none of them is actually a "good" wheel. How can I tell?

 

[Richard Baker]

Thanks, Don!