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Bench grinder

Another stupid boy Pike moment

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brian jones 1121/07/2021 21:07:02
347 forum posts
62 photos

Has this happened to you?

**************************

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 IoM21/07/2021 21:15:46
1248 forum posts
28 photos
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 yet21/07/2021 21:29:37
6734 forum posts
20 photos

Yes. Just fix it.

Steviegtr21/07/2021 21:51:31
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2422 forum posts
336 photos

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 1121/07/2021 21:57:07
347 forum posts
62 photos

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

Steviegtr21/07/2021 21:58:38
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2422 forum posts
336 photos

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

Steve.

brian jones 1121/07/2021 22:01:21
347 forum posts
62 photos

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 IoM21/07/2021 22:06:12
1248 forum posts
28 photos
did you swop the washers around as maybe the good one is now on the outside rather than inside against the shoulder?
brian jones 1121/07/2021 22:20:17
347 forum posts
62 photos

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 webster21/07/2021 22:31:51
3927 forum posts
61 photos

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

mechman4822/07/2021 16:02:55
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2947 forum posts
468 photos

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 1122/07/2021 16:44:43
347 forum posts
62 photos

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.smile o

watch this space.

DMB22/07/2021 16:53:17
1299 forum posts
1 photos

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

John

Nicholas Farr22/07/2021 19:03:56
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3312 forum posts
1529 photos

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 Ambrose22/07/2021 20:52:36
24 forum posts
3 photos

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 Man22/07/2021 22:08:05
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179 forum posts
31 photos
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 123/07/2021 10:23:38
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1808 forum posts
503 photos

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 Farr23/07/2021 10:41:44
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3312 forum posts
1529 photos

Hi, you may wish to peruse this information.

Mounting the Wheel

Regards Nick.

Robin23/07/2021 11:22:09
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539 forum posts

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

's loverly.

brian jones 1123/07/2021 15:58:14
347 forum posts
62 photos
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

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