Mounted points/stones

[Kram]

I bought a load of these last month as an alternative to carbide burrs in die grinder.

Go to use them and most dont run true and vibrate badly on low speed. These are new from Zoro and stored well. Would you expect the need to true up a burr with a diamond point on first use?

Some of these are big ones and its not a nice job, plus my diamond point is worn out.
I've trued the 5th one from left.

Then this little one. I may have been going too hard as my steel sheet was starting to glow at the cut then the tip pinged off. I do not want to be using the bigger/longer ones if/when they do that!
Do I need go be more careful with heat or is this a bad one?

 

[voipio]

Mounted stones will never put up with the same abuse that a good carbide burr will. They're not particularly strong, and are only held onto the shaft with a dob of epoxy.

 

[500e]

Always scare me running them at 15/20k had one burst and took out a fluorescent tube and its end socket, never found the other bits.
Wear a good full face mask, remember Max speeds vary as well according to make size and type

 

[slim_boy_fat]

I have the cheapy Lidl ones, if you overwork them the heat melts the adhesive [Araldite-ish stuff?] holding head to shaft.

 

[Mark 2]

No alternative to carbide.

 

[Kram]

I have burrs. I use both. Burrs Ive found its too easy to damage the work, stones are more controlled.

Small burrs are quicker than small stones but the bigger stones are quick and leave a nicer radius than I can manage with a burr.

The question is, should stones be ready to use or need to be trued up, or binned?

I notice my stones are getting a buildup of steel on the surface, I'd expect it with aluminium but not steel. Too much heat? How can I prevent it?

 

[tigdlo]

They look like resin bond, you could try vitrified but as with most things quality matters. If they are the kennedy ones the zoro listing doesn't say what type they are but they are aluminium oxide with "rubenite™" whatever tf that is, a google search only brings up mounted points, so probably a load of marketing BS.

Can't answer whether you should have to true them up or not but can't see it doing any harm, a silicon carbide wheel on a bench grinder would probably do a better job than a single point diamond.