Spin it in the lathe and bore it out with a diamond wheel dresser? (Cover lathe bed suitably etc first)

Yes, yes, it is a no, no!

If anyone on here wishes to advise a third party to make potentially dangerous alterations to a grinding wheel, then be it on their head should it all turn nasty (even litigation, like!).

Perhaps better to reduce the spindle size on the grinder, but that, too, may be sized for safety. Why not use the rarely used grinder with these cups?

Be safe. Industry insists on abrasive wheels being fitted and tested by a competent, trained operative, I believe.

I concur completely with Not done it yet who offers wise advice; the abrasive wheel regulation are rigorous and demanding, the manufacturers have to satisfy all kinds of requirements in wheel design and opening out the bore on a wheel will increase the risk of a wheel burst.

​This is one area where safety really matters and it just isn't worth the risk involved

Brian

Yeah, need a cert now if you want to do it at work, and even at college they prefer it if the teacher does the grinding, i was an exception because i had the cert.. Doesn't mean you can't go out and buy a 6000rpm cutting disk power tool, crazy laws.

The damage they can do though is pretty insane on the big stuff though, so you have a look at how many times this has gone to an act of parlement. No worse than some of the ginormous lathes can do as well. I vaguely know a guy who died using a very big wood turning lathe when a workpiece got thrown out. You don't really stand a chance.

I've heard of people using these on pillar drills when theres no room for any grinders. I use a buffing mop on the lathe but got too many uses for it to go without a proper bench grinder. They're the best part of 30 notes and do a good job, so theres no excuse really.

Overspeeding a wrong wheel or perhaps using it with the wrong material is one of the biggest causes of breakages, and breakages mean damage to you if you're not lucky. 

Few rules;

First of all, know what it is you want to grind, match it up with the right wheel AND the right speed, do not exceed the rating of the wheel. You check this against your grinders top speed in RPM. A good quality wheel will always have this information, if not then it's bin material. 

Then you have to check it for any obvious damage to said wheel, there is the "ring test" for any unseen damage, making sure the bore is a good fit on the wheel(or it will rattle around like nobodys business)

, card backing is intact and it is placed on the shaft with flanges both sides. 

Then you're good to go once everything is fastened up. Try to grind on the front face of the wheel if possible, as this minimizes wear to the wheel and it will probably need truing up from time to time. 

PS. I know that he's talking about a cup grinder so it would be different way of fitting it. It should still tell you what speed it can handle up to regardless. I think it's worth saying because this is basically what they teach you when you do this cert. 

Michael W

Edited By Michael Walters on 07/10/2016 09:02:55