Re-boring Grind Wheels

[Mark RandParticipant @markrand96270]

Posted by martin perman on 14/05/2022 14:04:13:

After reading the above I'm amazed that some suggested that opening the hole of a grinding wheel would be ok, as a retired service engineer I've had to repair centreless grinders and cylindrical grinders after a wheel let go, if they can bend metal then god help anybody daft enough to do it.

Martin P

Of course it's ok. How do you think the holes get made in the first place?

Opening up a hole or truing it isn't the same thing as cracking the wheel…

[martin perman 1Participant @martinperman1]

In a mould with the rest of the wheel around a former as told to me by a sales engineer when I was an apprentice.

Martin P

[bernard towersParticipant @bernardtowers37738]

Yes with you Martin they are moulded with the centre bush in the mould.

[SamsarandaParticipant @samsaranda]

Definitely moulded, you can see that if you look closely at the wheel before mounting it. Dave W

[BazParticipant @baz89810]

Martin is correct, some were, maybe still are made with a lead or lead like material in the centre, others are 1 1/4 diameter with reducing bushes, the only part of the wheel that you fiddle about with is the outside diameter, and that is with a dresser. I have seen wheels let go and the damage caused, only a moron would fiddle about with the bore, just my two cents worth, from someone who worked for a company making grinding wheels.

[Mark RandParticipant @markrand96270]

After which at least some of the bores are reamed to size, just as the outside surfaces may be machined to size.

One doesn't think twice about dressing the outside of a wheel (or shouldn't, anyway). The bore is no different from the periphery or sides.

They're ceramics, not magic.

Ring testing is something that should be done before mounting any wheel.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, on one of my abrasive wheel courses that I attended, we were shown a film about the basics of grinding wheel manufacture and the wheels were moulded and a thin cardboard tube was placed on a central mandrill in the mould. Once the wheels were set the next stage was to balance them and the process was automated in which the machine would spin the wheel and checked for balance, wherever there was any imbalance the wheel would have a calculated amount of chalk vibrated into the wheel and the wheel would be rechecked for balance and any additional chalk added in the correct places until satisfactory balance was achieved. On my courses that I've attended we were told the hole should not be altered and the sides should never be dressed. Dos & don'ts for abrasive wheels

Regards Nick.

[Nigel Graham 2Participant @nigelgraham2]

… with one of the Dont's now, in industry, being Don't replace a wheel unless you are trained and competent to do so.

Which means you would not even dream of trying to modify it other than conventional periphery-dressing!

[Mark RandParticipant @markrand96270]

Posted by Nicholas Farr on 14/05/2022 21:54:43:

On my courses that I've attended we were told the hole should not be altered and the sides should never be dressed. Dos & don'ts for abrasive wheels

Regards Nick.

The link is irrelevant. It's talking about resin bonded disks, not surface, pedestal or tool grinding vitreous wheels.

I'll leave people to their apprehensions and assume that none of them have ever had to do any form grinding, face grinding or endmill sharpening.

Have a nice day.

[Michael GilliganParticipant @michaelgilligan61133]

Not directly relevant to the current debate … But

From another recent thread:

.

It is interesting to note that the Current HSE Guidance is much less dogmatic than the old Regulations:

**LINK**

https://www.hse.gov.uk/pubns/books/hsg17.htm

… Well worth downloading ^^^

.

MichaelG.

[John PParticipant @johnp77052]

Posted by Mark Rand 15/05/2022 09:39:49

I'll leave people to their apprehensions and assume that none of them have
ever had to do any form grinding, face grinding or endmill sharpening.

———————————————————————————–

How very true ,bring up any of these grinding type of threads and you see
the same old stuff about the dangers .
I sharpen my milling cutters using a cnc machine ,add in the mix of grinding
wheels and computers to run them and a whole new bunch of scared to get out
of bed types will be posting on here.
Despite the abundance of so called experts on grinding there seems to be
very little or none written on the practicalities of actually doing it.

John

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