Bench grinder

[brian jones 11Participant @brianjones11]

Another stupid boy Pike moment

[brian jones 11Participant @brianjones11]

Has this happened to you?

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My 6" Clarkes bench grinder has sat in the corner doing its job without complaint for years, but the wheel had got grooved and the wheel was rather too coarse for a fine edge on HSS

So i thought Ill put a new fine wheel on and bought a named brand not cheap PRC – another story there

So imagine my surprise when it fired up and vibrated badly, particulary from wheel wobble

So i did some googling only to find this is a common and often difficult problem tosolve

worse still i put the old wheel back and that was no better

I had upset the balance of nature

Have any of you guys had this embarrassment ? (no facetious remarks pls)

[Frances IoMParticipant @francesiom58905]

The metal washers either side of the wheel often are very poor and need squaring or even replacing – one butts against a usually poorly cut shoulder. Also is either wheel too loose on the spindle

[not done it yetParticipant @notdoneityet]

Yes. Just fix it.

[SteviegtrParticipant @steviegtr]

My grinder has various bushes to make up the correct diameter of the wheel used. I ended up making new ones as they were not very good. All good now. Also if you can get hold of a truing diamond it can help.

Steve.

[brian jones 11Participant @brianjones11]

its not the radial run out I am concerned about as this can easily be sorted with a diamond tee bar dresser, its the side wobble that shocked me. Ive seen a dozen vids (most are old blow hard rubbish) but some have made serious attempts at the problem

Its not a trivial matter and took me by surprise

[SteviegtrParticipant @steviegtr]

Is there any bushes in the centre or is it a perfect fit on the steel shaft.

Steve.

[brian jones 11Participant @brianjones11]

both wheels old and new came with delrin bushes 1/2"" for the wheel

gets me i can even reinstall the old wheel as it was, it has devloped a wobble which it never had before

cant figure how this has gone pear shaped

[Frances IoMParticipant @francesiom58905]

did you swop the washers around as maybe the good one is now on the outside rather than inside against the shoulder?

[brian jones 11Participant @brianjones11]

I replaced them as they came off. I am going to try a few more tricks tomorrow and get a dti on the job, make up new plates, cardboard washers, what a palaver. my m/c vibrates so badly its barely usable, no vibes without the stone btw.

this has never happened to me before but then i dont remember ever changing a grinding wheel.

[duncan webster 1Participant @duncanwebster1]

My el cheapo grinder vibrated quite badly, so I bought a new wheel with 1.25" hole and made new washers, the one nearest the motor has a boss to fit the in the wheel, just a bit shorter than the wheel so the other washer clamps up. this new thick boss/washer has 2 grub screws to hold it to the shaft. All unbalance problems gone away. I cribbed the idea off a RJH Ferret grinder

[mechman48Participant @mechman48]

As an aside ; are the bearings on the shaft starting to go, do they 'rumble' when you start the motor up?, it usually is one of the above reasons though.

George.

[brian jones 11Participant @brianjones11]

Hi George, no rumble, indeed the grinder hasnt had much use in 10 years

BUT I have a cunning plan which is painfully obvious and hasnt so far been suggested to me.

watch this space.

[DMBParticipant @dmb]

Thanks, Duncan, never thought of that solution. Will bear it in mind, should I ever have grinder trouble in future.

John

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Brian, if the retaining discs either side of the wheel are the pressed type, you may have inadvertently over tightened the nut and distorted them, if so you should replace them.

Regards Nick.

[David AmbroseParticipant @davidambrose86182]

There may be a dynamic balance interaction between the two wheels. You could try moving the new wheel round the shaft, say 10 degrees at a time, to see if it makes any difference. I recall being taught this as an apprentice.

[Oven ManParticipant @ovenman]

Posted by duncan webster on 21/07/2021 22:31:51:

My el cheapo grinder vibrated quite badly, so I bought a new wheel with 1.25" hole and made new washers, the one nearest the motor has a boss to fit the in the wheel, just a bit shorter than the wheel so the other washer clamps up. this new thick boss/washer has 2 grub screws to hold it to the shaft. All unbalance problems gone away. I cribbed the idea off a RJH Ferret grinder

+1 for Duncans arrangement of integrated boss and flange. I did the same with very satisfactory results. I didn't use any grub screws, just the original outside flange and clampling nut. The major benefit of this arrangement is that the long hole, being a good fit on the spindle, holds the wheel nice and square and eliminates any wobble.

Peter

[David George 1Participant @davidgeorge1]

Hi Brian the inside washer holds the wheel square and I have made washers like Peters with a boss on the end that just slides over the wheel spindle and has a shoulder of a smaller diamiter to stop it being pushed on too far. The washer side should be the same diamiter as the original washer and relieved so that the outside 12 mm band grips the paper washer and wheel and doesn't stress the wheel.

David

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, you may wish to peruse this information.

Mounting the Wheel

Regards Nick.

[RobinParticipant @robin]

I knew nothing about bench grinders so I typed, "Which bench grinder?" into Google and then bought a Metabo DS200.

's loverly.

[brian jones 11Participant @brianjones11]

Posted by Robin on 23/07/2021 11:22:09:

I knew nothing about bench grinders so I typed, "Which bench grinder?" into Google and then bought a Metabo DS200.

's loverly.

but have you change a wheel yet?

which is the point of my OP, I was floating along then disaster

but I have a cunning plan which I am trying out just now

[Howard LewisParticipant @howardlewis46836]

Even with a new Clark grinder there was vibration. Dressing the wheel cured that.

But a a shouldered inner washer n which is close fit on the shaft should go a long way towards curing side to side wobble.

The final op has to be dressing the wheel so that the OD is concentric with the shaft.

Howard

[brian jones 11Participant @brianjones11]

Indeed correct sir, and dressing the wheel for radial run out is common practice and sensible

What customers dont realise is that the crude washers and loose fit of wheel on the shaft was never intended to be a means for mounting the wheel squarely – they dont tell you that and it doesnt appear in the largely trivial vid offerings on youtube

in the factory, the wheel is assembled in the vertical axis on its end using a jig to hold the wheel square, then the nut is tightened lightly (by its direction its naturally self tightening), just replacing the wheel in situ is almost certain to fail unless you go to the trouble of making a precision mandrel adapter for the job – as detailed by members above, who clearly also discovered the trouble of wheel wobble

[RobinParticipant @robin]

Posted by brian jones 11 on 23/07/2021 15:58:14:

but have you change a wheel yet?

I did pop one out just to see if it was as easy as claimed.

[brian jones 11Participant @brianjones11]

Well what you failed to mention was that this is an 8" wheel (200mm) and it costs £175

which is way above most cheap charlie 6" m/c @ £25

https://www.ebay.co.uk/itm/333074933788?epid=2255630625&hash=item4d8cd0281c:g:5n8AAOSwWkFcZqdp

IMHO thats a bit naughty and OT

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