Diamond wheel adapter for bench grinder

[PekkaNF]

I had a nice cheap but solid bench grinder that has been lying basically unused.

Looks like a perfect canditate for diamong wheel. Bought one and measured shaft/bore/adapter sizes. There is a loose boss on the shaft that looks complicated but all features are needed...desided to make a bushing. It looks awfull but crosschecked the diameters and feel....looked fine.

All went really well and nice hand tight fit.

But when I put diamond wheel on it was about 0,2 mm excentric. Wish I had it clocked before efort.

Pekka

[PekkaNF]

What to do?

Desided tu remake the whole thing out of two parts. It all went together pretty good.

BUT when everything was together and brought from cold garage to inside the ID was loose least 0,1 mm...bummer.

Pekka

[PekkaNF]

I was thinkking that pressing the ring should make it tighter, not loose. Maybe I had zeroed it wrong or had dirt, even when I measured it multiple times.

Maybe it is the caliber I use in cold garage and took mitutoyo from warmth of my home into cold world of repetition.

SOOOO...I made another smaller bushing. This time I used hollow bar, turned outside near, then inside to exact and lastly outside to exact. I used the big display garage caliber and cross check with teh mitutoyo. Both were close, but I choose to trust mitutoyo on this one. It was either just a hair tight or "perfect".

Pressed the collar over the bushing and rushed inside to chek.

IT CAME TIGHT, further measurement conformed that it was just annoying 0,03 mm too tight. i was considering of heating it just a little, but it may need to come off near future.

I was rummagin my reamers and I just knew that I did not have a proper 15 mm reamer, but I ahve two adjustable reamers and lucily I had 15 mm adjustable reamer. I adjusted it just snug inside the hole and gave it fast go.

Now it fits.

But diamond ring and the aluminium backinng disc are not exactly in same plane. It does not need much, but it has just a small wobble.

How to true diamond disc?

Pekka

[shipto]

I believe it has to be a diamond dresser?

[Pete.]

If that's a CBN wheel bonded to an ally disc I think that dressing it won't be easy. I rad that someone used green wheels on a surface grinder to dress them but if I were in your position i would very carefully hold the OD in a chuck and face/bore the ally part slightly.

[PekkaNF]

It is resin bonded diamond. I have been trying to find CBN wheel, but no luck yet.

Found this info
Resin-bonded diamond wheels can be quickly trued, using a silicon carbide brake controlled trueing device.

http://www.arceurotrade.co.uk/projects/d_wheels/dwdoc2.html

Hmmmmmmm....so diamonf wheel spins faster and truing wheel spins slower?

Then again:

For truing the diamond wheel was spun at 100RPM while the silicon carbide wheel was spun to 3500RPM

Maybe important thing is only speed difference?

I was trying to figure out how to mount the diamond cup wheel true to lathe chuck and then true the boss...it needs only very little. Would need to make mechanical mount, maybe screws to face plate outside of the boss?

Pekka

[chipenter]

The only way I could get mine to run true , was to clamp the grinder to the lathe bed and run it to skim the spindle .

[Will_D]

I know this old but I have just had a similar problem:

Before doing anything I suggest you check the concentricity of the diamond wheel. Mine was a 'straight cup'

I made up the 32 adapters according to Harold Hall's books and the wheel was running out of true.

I didn't skim the grinder's shafts as they appeared were true running.

I chucked the 32 mm bore onto the lathe chuck and found the wheel was out by about 0.15 mm.

Skimmed the od of the cup wheel (but ignored the bonded diamonds (waiting for a suitable dresser))

Runs much smoother than at first.

[PekkaNF]

The diamond/resin rim on my wheel was wobbly and I trued it with silicon carbide wheel. Silicon carbide wheel wore more than 10x speed to diamond wheel, but the diamond came pretty true.

Pekka