GRINDING ON SIDE OF WHEEL

[steam4ian]

G'day All.

The topic heading will provoke a response I hope.

I was always taught to ONLY grind on the circumferential face of the wheel and never on the side. I reckon if grooves had been found on the side of a wheel at BHP there would have been an enquiry; probably followed by a DCM!

I note that some articles on grinding show the tool being against the side of the wheel.

What is the wisdom of the group? (There's an assumption made hear? )

Regards,
Ian

[circlip]

Is it a bird ?Is it a plane? no, it's the bits of a grinding wheel thats burst, traveling faster than a speeding bullet, WHEREVER it bl--dy likes. Joking apart, I suppose lots of us have done it, and GOT AWAY with it, but we shouldn't, and it's a bad example to show the "Kids" on this site. As the book says, use a CUP wheel, yes it takes time to change, but if you sharpen a BATCH of tools together, from a safety point of view, you know it makes sense.

And yes, I've seen one GO, luckily from a distance.

[modeng2000]

Are there any observable indications or tests that might indicate the health of a wheel?

John

[modeng2000]

The only tip I remember from a friend in the Mech. Workshop where I used to work was that the wheel should be checked that it 'rings' much like say a cup when tapped suggesting that it was not cracked before it is fitted.
Don't know if the same would work when on the spindle.

John

[ron]

It was a hanging offence when I was an apprentice, I've done it and got away with it but I always stand to the side of the wheel just in case, as previously posted it's showing a bad example.
Ron

[houstonceng]

The other problem with using the side of a wheel is that it's not been dressed so it has a closed grain structure and, therefore, creates a lotta heat and not much grinding so the tendency is to press a little harder leading to the cat-as-trophic failures mentioned.

Have I done it ?

Well I'm sure you can guess for yourselves but I've never had a wheel burst.

[circlip]

Yes modeng,balance the wheel with your finger in the bore and give a tap. A good wheel will ring, a bad one clunks, and its difficult trying to do it on the spindle.Colours:- blue /grey, general cleaving, White/pink, normally for grinding hardened materials,gives a finer finish than previous but becarefull not to overheat workpiece. Green, carbides. CUP wheels, grind on wide face, NOT edge. We only grind on side of wheel(OH NO WE DON'T) cos it's a longer grinding face. How about guards? Well we keep having this discussion about the amount of disposable income we spend on our hobby so with the price of bench grinders being so cheap, one can leave a cup wheel on one and make a guard to suit.
Did you check for the ring drJohn? Never seen one ring and bang, but I never put one on if it didn't ring.
Modeng, if it LOOKS cr3p it will be so don't use it AND smash it and dump it, so no one else can try to use it.

[modeng2000]

Circlip, When I got my first double-ended grinder the Workshop Manager told me to dispose of the supplied wheels and get a pair from a trusted supplier. The originals might have been OK but sometimes you only get one chance don't you.
I've never witnessed an exploding wheel and I don't think I want to.

John

[Prowe]

Hi all,
Never underestimate the power stored in a rapidly revolving grinding wheel, I have never forgotten the occasion when I was an apprentice and I witnessed a wheel “bursting”.
This was on a surface grinder and the fragments from the shattered wheel went straight through the Perspex safety screens at each end of the table, through windows and metal tool cupboards and one piece was later found embedded about ½ inch in a brick wall.
In all fairness to the wheel, this was the result of the operator’s inattention/carelessness/stupidity or whatever you wish to call it, he had tried to take a cut of about 50thou under power, but the vision of those wheel particles flying through the air has remained with me for nearly 50 years. Fortunately no one was hurt in this incident apart from the operator’s pride, but it could have been so very different.

I would like to take this opportunity to thank the contributing members of this site for all the invaluable information that is so freely given, rarely does a day go by where I have not learnt something new.

Seasons Greetings to you all.

Regards,

Phil

[Arnak]

Hi Guys,

I did see a very small one explode from an internal grinding machine.

The guy had been on a grinding wheel course so he knew what he was doing but it still exploded.

It was a 4" diameter very high speed wheel running on a long spindle.

He did everything right, checked it before he put it on the machine, then ran it up slowly a few times, then just as he was about to get going with the grinding it blew apart!!!

As it was an internal wheel there was not guard, he was quite rightly standing to one side just in case, luckily for him!

One part of the wheel shot 30' up and across the workshop, straight through the foreman's window and embedded it self into the brick wall at head height, just were the foreman would normally have been standing at his desk!!!

Nobody was sure whether is was good or bad luck that he wasn't there at the time....

Arnak

[paul]

Eeek, this is a scarey thread! Apart from not grinding on the side of the wheel, checking if a wheel rings, not trying to take too heavy a cut and standing to one side, does anyone have any other tips to avert disaster?

EDIT: The guards on my grinder were almost completely opaque and as a result spent most of their time flipped up out of the way... I've just been and made some nice new ones out a sheet of thicker perspex!!

[circlip]

You can class ALL the equipment we use as scary, but once the basic rules of safe operation are pointed out and evaluated, then it's up to the operator. At least one then has the informed options of other people's experience to choose how close to the line of safety you think you can get away with. I'd like to wager that the Elfins would go ape at atleast one of everyones methods of operation we use in our workshops that can't be used in industry. Hindsight is a superb teacher, work safely.
Just had another thought about "side" grinding, How many photos of drill grinding jigs are shown set up on the side of the wheel? ? ?

[paul]

In Peter Wright's 'Model Engineering - A Foundation Course' he strongly warns against using the side of the wheel but in the part on sharpening drill bits proceeds to show photo's of someone doing just that!

[steam4ian]

G'day Sir Ian Clip, Paul et al.

These pictures and grinding aids are exactly the problem which got the topic started.
For me I think I can solve it by getting a cup or dish wheel, a local tool shop can order them in for me at reasonable cost. The elcheapo grinder I got for the ask has no end float which is an encouraging start.
Brag time, I had a go at sharpening a 4 flute end mill today using the standard grinder; I actually improved it! Confession time, I blunted the mill trying to turn a dead centre into a half centre. I did a file check and though the steel was softer than it turned out to be. I still got my half centre, but by grinding not machining.

Regards to all,
Ian

[steam4ian]

G'day all.

Here's a gory story.

At BHP steel mill in the safely lecture room sits a large grinding wheel. Wedged on to the stone is fabricated C clamp. Around the periphery of the wheel are what appear to be three chalk lines.

The incident involved an apprentice making a clamp which was used to hold caps over flanged pipe ends. The material was inch thick MS plate flame cut to a C shape. For some reason the lad decided to use a general purpose grind stone to clean up the inside of the C. His logic was that the wheel was thinner than the finished opening so he pushed the C on to the wheel. Exact events are unclear but the wheel grabbed the C drawing in his hand before the wheel finally jambed. The "chalk" lines were the marks made by the bones and knuckles of his first three fingers. They saved his thumb and little finger.

Regards,
Ian

[lancelot]

Hello folks,
the subject of Grinding wheels and the process of fitting them was part of the one year tool room training course at college, there we were shown the ''Ringing'' trick as referred to by John, what wheels to use for each purpose, and how to fit them safely...the use of the side of the wheel on a Standard buff or Grinder is as said a NO NO...not in so much as it could cause a burst, but that if the operator was over enthusiastic the object that he was grinding could very well jam the wheel (NO rests or guards in this position) thus causing a burst...We were also shown the most important part of the process, which is the ''BALANCE'' of the wheel, many wheels of very poor quality were evident...when we had to change a wheel for any reason on buff or grinder, the wheel ''HAD'' to be checked for ''BALANCE''... this was done on a special rig which allowed for the wheel to be checked for out of balance condition...at times up to 6 wheels had to be tested before one was deemed suitably near to being on balance... the wheel was then fitted to the relevant machine using the correct procedure for that machine, then carefully trued up with a Diamond dressing stone to ensure that the wheel ran true.
All the best for now,
John.

[circlip]

Been there, seen it , done it AND got the certificate to say I had successfully completed the safety course to enable me to mount grinding wheels onto the steel carriers for surface grinders. The difference is lancelot, these wheels are rotating at speeds far nearer their bursting speed than we are likely to achieve on our bench units but the same BASIC precautions should still be observed. Some other points I missed was that the BORE of the wheel should be a close fit on the shaft of the grinder, adapter washers should be supplied with the wheel if they are necessary, and ALWAYS fit thick paper washers on EITHER side of the wheel between the wheel and the steel/aluminium clamping washers. Wheels usually have these supplied as the specs are printed on them. One can only assume that the FORCE generated on the side of the wheel in drill grinding/sharpening is so slight, cos we're not CLEAVING, as to be classed as "SAFE"

[Richmond]

From a safety point of view Perspex should NOT be used as a guard on machinery, it shatters almost as nicely as grinding wheels when impacted.

LEXAN is the preferred choice as it is almost shatterproof in comparison.

Just my 2p worth

Rgds
Keith

[petercolman]

Whell the elf n safety boys have had their say, and all power to them, shall we start on all other home workshop operations while we are at it - milling, drilling without chuck guards and no clamp on the vice, lathe chuck guards.
Lets face it, most of us are working on our own and break the rules in some way each time we use our workshop, the question is dowe use the side of the grinding wheel, yes I suspect we all do and it works, take care and you will be OK.
If you want a horror story read The Gun by W.W. Greener who made shotguns in Birmingham, rough forged barrels were ground to shape by hand on natural stone wheels, the operators were highly paid and several died each year, Greener maintined that they knew the risk, and thids is my point, you also know th risk so take care and use common sence.
happy new year
peter

[Richmond]

HI,

I am NOT a health and safety freak, but my eyes as well as fingers / hands are the most important things to me to enable me to keep doing the hobby, so I do wear safety specs, and I keep my fingers well away.....

Some people dont use guards. I dont on my lathe or mill. However, all I am saying is if you feel the need to fit one then use Lexan and not Perspex.

Rgds
Keith