scarey bench grinder

[astrid]

Bought an old bench grinder at a garage sale last month.
the brand has worn off so I cant tell you what it is but it must weigh 30kg or more
The problem is when I turn it on the whole shed shakes like a quake and every thing starts falling off the shelves.
Its got two stones and solid cast iron mount.
is there anything I can do to stop the vibes
my shed is on concrete stumps off the ground with a tounge and groove floor
The bench is built in.

Astrid

[DJ’s Timber]

Sounds like you've either got a bent shaft or a badly out of balance grinding wheel. If it's a bent shaft, there is not much you can do or if it's the stones, simply replace them.

To find out, you need to take both stones off and then run the grinder and see if it still vibrates, if it's the shaft the vibration won't be as bad without the stones but should still be noticeable.

[Groggy]

Sounds like you've either got a bent shaft or a badly out of balance grinding wheel. If it's a bent shaft, there is not much you can do or if it's the stones, simply replace them.

To find out, you need to take both stones off and then run the grinder and see if it still vibrates, if it's the shaft the vibration won't be as bad without the stones but should still be noticeable.Agree with DJ - be careful the wheel doesn't disintegrate from the vibration.

[aussiecolector]

If it is the stones try dressing them. It is common for them to get out of round.

[jmk89]

If it is the stones try dressing them. It is common for them to get out of round.

If it's that bad, tho', you will need a star wheel to knock off enough to get them round.

Are you sure that the wheels have the right diameter bush for the arbor? If not, they could be moving around which they are spinning. DJ is right - test the grinder with the wheels off. If the arbors wobble at all, you have a problem there.

[astrid]

thanks guys,
I havent really run it yet, Ill take the wheels off and see if it improves the situation.
At the moment its sitting on the floor. figured it wouldnt shake as badly as on the bench.
It really is a noisy big thing though, you can feel the power it drawers as you turn it on.
are these old things safe?
Astrid

[aussiecolector]

It should be safe, run it through an earth leakage switch.
Another thought, check the bearings for wear. you could replace them for under $20 if you do it yourself.

[BobL]

Taking the wheels off is a really good idea and see if it spins smoothly.
I would also inspect the wheels for any cracks and chips.

Then put one wheel back on at a time that way you can maybe identify if it's one or both wheels.

[Woodlee]

thanks guys,
I havent really run it yet, Ill take the wheels off and see if it improves the situation.
At the moment its sitting on the floor. figured it wouldnt shake as badly as on the bench.
It really is a noisy big thing though, you can feel the power it drawers as you turn it on.
are these old things safe?
Astrid

Astrid ,
Check the grinder as others have said .
To check the wheels for cracks you hold the wheel through the hole in the center on the tip of your finger and tap it gently with a screwdriver handle .If you hear a ringing sound the wheel should be ok .If it replies with a dull clunk ,just toss it and get a new one.Best to actually break it up and then toss it in the bin .Also any big chunks out of the wheel may indicate it has been dropped .Check to make sure the bushes in the wheel mounting hole are correct size also.
The damage these things can do if they shatter at speed is absolutely amazing.

Before you start it loosen the rests (if it has them ) and slide them back get a stick or similar and rest it on the rest like a pointer ,rotate the wheel by hand slowly moving the stick toward the wheel face and check the gap as you go for any runout on the wheel.
If you have a lot of run out you will need to true the wheel .

here's a good link with some good pointers.

http://www.safetyline.wa.gov.au/PageBin/mechhazd0001.htm

Kev.

[astrid]

thanks everyone,
This all sounds a bit technical for me.
I might clean it up and send it to a guy in malvern to check it over.
It was only $20 so its no great loss if its cactus
and if its basicly OK I can afford to get new wheels and bearings.

Happy christmas

Astrid

[kman-oz]

Bring it with you on the 5th and we can look it over. Is it a 6" grinder? If so we can test it with my wheels too.

[astrid]

Thanks, Kman
I will if I can get someone to lift it off the floor!
I cant pick it up took two to get it in my shed/

See you on the 5th

Merry Christmas

Astrid