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.


"Catherine Jo Morgan" wrote in message
...
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.

"Catherine Jo Morgan" wrote in message
...
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.


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

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.

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

"Greg O" wrote in message
...

"Catherine Jo Morgan" wrote in message
...
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.

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).


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


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

"Catherine Jo Morgan" wrote in message
...
| 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.

On Fri, 18 Mar 2005 21:50:41 -0800, Grant Erwin
wrote:


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.

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

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

On Fri, 18 Mar 2005 23:29:26 -0600, Greg O wrote:

has a wheel balancing kit but believes that it's the whole base that's
vibrating, not just the wheels.

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.

--
"Keep your ass behind you"
vladimir a t mad {dot} scientist {dot} com

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


"Catherine Jo Morgan" wrote in message
...
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.

R. O'Brian wrote:

... all single-phase motors vibrate torsionally. ...

So, DC would be a better choice for grinders?

DC or 3-phase AC.

Randy


"Bob Engelhardt" wrote in message
...
R. O'Brian wrote:

... all single-phase motors vibrate torsionally. ...

So, DC would be a better choice for grinders?

On Sat, 19 Mar 2005 08:11:48 GMT, Gunner
wrote:

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.

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.

On Fri, 18 Mar 2005 22:30:47 -0500, "Catherine Jo Morgan"
wrote:

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.

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.