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Bench grinder improvement mod.

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Rik Shaw23/05/2014 19:03:33
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1292 forum posts
350 photos

I have several bench grinders all of an eastern persuasion and all have the same design of grinding spindle nose as shown in pic1.

grinding spindle.jpg

The problem here is the miniscule "flange" arrowed at "2" which is supposed to help stop the wheel from wobbling from side to side.

 

I bought yet another grinder from the boot last weekend for a couple of quid and on trying it out when I got back home I could see why they wanted to get rid of it. One of the wheels was running so far out it was dangerous to run it up to speed, so I have set to and come up with a mod which corrects this problem on these cheap Chinese machines.

My corrective flange now relies on diameter "1" for eliminating sideways wobble on the wheel. The flange is bored out to be an accurate fit on diameter "1" and flange edge "2" now becomes a simple stop. The shoulder which goes up against this "flange" can be seen inside the bore on one of the other pics.

grinder flange001.jpg

grinder flange002.jpg

You can see the results here:

 

p://youtu.be/n51JPRkj85I

Rik

Edited By Rik Shaw on 23/05/2014 19:05:59

Tony Payn30/05/2014 21:34:47
10 forum posts

Hello Rik

That's a neat way to rescue a condemned grinder and is an improvement that ought to come as standard.

Thanks for sharing it!

Tony

derek hall 107/10/2018 08:05:58
40 forum posts

Hi all, sorry to resurrect an old thread but...

The original design of locating wheels as seen on many bench grinders, including my new 8 inch arc Euro trade Allwin is a poor design.

Does the modified design improve things as shown by Rik in the original post I.e. side to side wobble?

In passing how come so many grinding wheel have holes that are non standard. Does this mean that you have to buy or make a bush to suit and what sort of "fit" to wheel and shaft should we be looking for?

Finally! Should all new grinders/wheels to dressed before use and for the standard wheels is a single point diamond suitable?

Regards to all

Del

Mike Poole07/10/2018 10:45:14
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1957 forum posts
46 photos

Many wheels have a standard 1 1/4” or 31.75mm hole and are bushed to suit grinder shaft. The shoulder on the shaft is an inadequate location especially for the typical pressed flanges. I make a new inner flange with a 31.75mm boss for the wheel, make the hole for the shaft a push fit and it should keep the flange running true. You will probably need a new wheel as they are often made with the hole to fit the shaft. The wheels will need dressing to run true and I will do a one time dress to the sides to true them which I feel a 25mm wheel could take without causing a problem. I do not recommend this from the position of being an expert so do it at your own risk. A smooth running and true wheel is a pleasure to use.

Mike

DMB07/10/2018 11:29:15
885 forum posts

Cromwell Tools sell sets of plastic bushes in diff. dias., especially for mounting grinding wheels of various bores. No fin. Interest, just satisfied customer. I once purchased a white cup wheel from them and a set of bushes.

mechman4807/10/2018 16:52:38
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2384 forum posts
372 photos

http://youtu.be/n51JPRkj85I …

comes up with 'video not available' … ?

George.

John Baron07/10/2018 17:36:44
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77 forum posts
13 photos

Hi Guys,

That tiny lip becomes an issue with the cheap nasty monkey metal flanges that seem to get supplied with most grinders nowadays. A good close fitting washer works wonders, extending the bore of the washer is even better !

Better still is facing the washer square actually on the grinder shaft.

Don't forget to use blotters on each side of the wheel.

Neil Wyatt07/10/2018 19:53:34
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16066 forum posts
675 photos
73 articles

3D printing seems an obvious route for making custom bushings.

Whatever you do, don't forget the card washers!

Neil

Robert Dodds07/10/2018 20:48:18
258 forum posts
29 photos

No mention has been made so far about the need for both flanges to be similarly recessed away from the bore so as to put even clamping forces on the wheel. There are some clear illustrations in a HSE handbook on the subject that's free to download at (http://www.hse.gov.uk/pUbns/priced/hsg17.pdf).
I particularly note that if you have over a 500W motor the inner driving flange should be keyed or otherwise fixed to the drive spindle.

Bob D

Pete Rimmer07/10/2018 22:31:49
329 forum posts
7 photos

I've done that to all of my grinders. You get a nice true-running wheel and a wide choice of grits and hardnesses.

Michael Horner08/10/2018 07:36:51
199 forum posts
53 photos

For this, I added larger flanges, using adhesive, to the grinders spindles and turned these true with the grinder running whilst fixed to the lathes bed. The advantage of this, together with the accurately made adaptors, is that the wheels can be interchanged and only need truing up the first time they are run.

**LINK**

The above is from Harold Halls website of how he dealt with the issue.

Cheers

Michael

Rik Shaw08/10/2018 10:03:49
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1292 forum posts
350 photos

"comes up with 'video not available' … ?"

Thanks for pointing that out George, it looks like YouTube have "lost" my vid. I have checked back on some of my other movie links associated with posts here and they all seem intact .

As the "before and after" can no longer be viewed I can confirm that the mod worked well and the wobbly wheel was made to run true.

Rik

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