how to minimize vibration in a bench grinder?

I have a woodworking friend who's bought a good grinder for sharpening turning tools. She's mounted it on a regular metal post-style grinder base, but it vibrates a lot. Is there a better base that would minimize this? She has a wheel balancing kit but believes that it's the whole base that's vibrating, not just the wheels.
Advice will be much appreciated.

Take the wheels off and see if it still dances.
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A heavy base is better. My grinder base is an old brake drum, welded to a pipe for a riser, with a plate welded on that the grinder is bolted to. Then the whole works was filled with concrete. Probably weighs 150 pounds. Greg

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The base may have a resonant mode right where the grinder's vibration is. Add or subtract weight to it. Or reduce the vibration amplitude (i.e. by balancing the wheels). Running the grinder without the wheels is a real good place to start. Guys whose drill presses vibrate sometimes fill the column with sand and then oil, or even concrete, or clamp the column to a wall.
GWE

On Fri, 18 Mar 2005 21:50:41 -0800, Grant Erwin
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Lay a 25lb bag pf #7 1/2 bird shot on top of the grinder. If there are vibration issues, this will deaden them, and one can use the same bag to diagnose where the problem is coming from.
Gunner
Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats. H. L. Mencken

wrote:
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That is an excellent idea. The size of the shot doesn't really matter, but a bag of shot is an excellent damper. Catherine, you can probably get used shot at a local range. A range near me sells it in gallon jugs. It's considerably cheaper than new shot and it works just as well.

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She
It's unlikely the vibration is caused by anything besides the wheels. Often the sides of a wheel must be dressed because they are not parallel, making one side of the wheel heavier than the other. No way it will run without vibration if that be the case. In order to dress the sides, care must be exercised, and a diamond point used to minimize risk of breaking the wheel(s).
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Very nice setup. Weight is definitely to your advantage, and the wheel is a convenient foot rest for those long hours at the grinder!
A friend that used to run a fab shop made my base. He used two 2" square steel tubes on 5-1/2" centers, front to back. These are welded to a base that's 3/4" thick x 15-1/2" diameter, and a top that is made of 8" channel, 20" long. It turns out to be very rigid, much better than a single column support. I have a wet diamond setup on one end of the motor, and an aluminum oxide wheel on the opposite end for HSS> I bolt mine to the floor to prevent any movement. I get no vibration.
Harold

On Fri, 18 Mar 2005 23:29:26 -0600, Greg O wrote:
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The whole base may indeed be vibrating, but the source of the vibration is the wheel(s). That wheel balancing kit is the first step. Keeping the wheels true is the second step. A solid, vibration-damping base is the third step. Sandbags will work better than the same mass of solid concrete.
Someone else can inform us whether the contact between wheel and work can cause vibration problems. I don't know about that.

| I have a woodworking friend who's bought a good grinder for sharpening | turning tools. She's mounted it on a regular metal post-style grinder base, | but it vibrates a lot. Is there a better base that would minimize this? She | has a wheel balancing kit but believes that it's the whole base that's | vibrating, not just the wheels. | | Advice will be much appreciated.
I have a small grinder directly mounted to a 1/2 ton truck brake drum. I have it on an old piece of carpet to quieten it and whatever table I set it on considerably.

Even if the wheels and rotor are perfectly balanced, all single-phase motors vibrate torsionally. The source of the vibration is the counter-rotating magnetic fields in the stator reacting with the rotor. The only remedy is adding mass to the motor or motor mount. That's why quality tool grinders have very heavy motors/mounts or use 3-phase motors. For standard motors such as used in a A/C system blower, fans, etc.,a rubber ring mount is often used to minimize noise and vibration transmission to the housing.
Randy
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She

R. O'Brian wrote:
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So, DC would be a better choice for grinders?

On Fri, 18 Mar 2005 22:30:47 -0500, "Catherine Jo Morgan"
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A single post must be quite heavy to be stiff. The mount for my 2HP buffer is an H-type base with a single column, both made of 2" square steel tubing. That alone is far too flimsey, but diagonal struts from the tips of the H to the buffer mounting plate made it very stiff -- and it's still light enough to move easily.
I needed a rigid stand because ya don't "dress" a buffing wheel, gotta use it like it comes and they're never perfectly balanced.