What can be ground on diamond wheels?

[julianf]

I have a grinder with a diamond wheel here that I only ever use to grind tungsten carbide engraving cutters.

I'm sure I remember someone telling me once that if you ground steel on a diamond wheel it just gummed up the wheel.

Ive never had cause to think about it before now -

I have chipped the end off a tiny m2.5 tap. A £15 one. I'd like to grind a nice tip back onto it, as it's only the end that's gone and I think that might work.

But it's a £15 tool Vs a £90 or somthing wheel, so it would be false economy if it was going to mess up the wheel.

Can anyone give me clarity on this?

Thank you.

 

[brightspark]

well diamond cutting disks used on concrete certainly dont like cutting through the rebar and can wear them out real quick

 

[James1979]

They sharpen stump grinder teeth well.

They’re basically a lathe tool, with tungsten (I think) brazed onto a steel finger. If you catch the steel it doesn’t really hurt them. It’s more if you put too much pressure on and overheat the wheel.

 

[optima21]

ask the manufacturer what they recommend, I grind high speed steel and tungsten carbide on diamond wheels, but the cup wheel I use cost about £10

 

[Screwdriver]

The issue will be heat. If you get the wheel too hot it will soften the resin bond, assuming you have the cheaper bonded type (like most of us do).

Another better type is something like a sintered metal bond, effectively welding the diamond into place. They might still "gum up" with a softer steel but either type will be fine with a hardened tap. Just be careful with cooling or ideally, take light passes and don't heat it up too much.

 

[Hopefuldave]

The heat from grinding can be enough to get the diamond where it contacts going into solution in the iron/steel, similar for cutting tools - ruined a very pricy polycrystaline diamond lathe tip on steel, its twin works brilliantly on ally, Ti, bronze... Yes, I forgot it was there, thought it was carbide

Dave H. (the other one)

 

[Spark plug]

Back when I worked in the engraving industry, like you say we used diamond wheels for carbide cutters and a white aluminium oxide wheel for HSS cutters. Not that many people still use HSS for engraving these days but you do still see them now and then.

 

[Munkul]

A small amount of HSS is extremely unlikely to mess up your diamond wheel. Obviously it would fast knacker things if you only ground steel on it...

My only experience with diamond wheels is tungsten grinders, and they can tolerate a little bit of steel contamination just fine.

 

[daleyd]

Drill sharpeners use diamond wheels and are used to sharpen HSS all the time

 

[Bullet2012]

You can round off the nasty sharp end of screws and nails, thereby helping prevent them digging into your skin when safely stored in your pockets.

 

[mike os]

Hard materials

 

[not done it yet]

Apart from never paying that much for a M2.5 tap, I grind my HSS cutting tools with a general purpose grey wheel on a bench grinder. I would grind carbide on a green grit wheel (carbide might be nearer 15 quid a throw).

Only for fine finishing of cutting edges would a better (precision) grinding wheel be used.

Stick the tap in a drill and use a bench grinder would be my repair method - if it is HSS.