Diamond stone dressers

better

gross

Peter,

There are two processes here which are distinctly different: Shaping and sharpening: A wheel can be used for such a variety of applications it is difficult to be specific so lets consider a simple bench grinder. A/ Let's imgine that you've used it for general grinding, tool shapening etc and its developed a groove in the periphery - you would use the diamond to dress it back to being a true cylinderical surface .B/ Now lets imagine you've used it to grind too soft a material, or at too slow a speed, or for that matter grinding correct material over a long period. Two problems develop. The wheel becomes 'loaded' and particles of the material you are grinding have become imbedded between the grains of abrasive and binder. Also grains of the abrasive become bluntened - so it no longer cuts properly and the work overheats so the wheel needs sharpening by dressing . This plucks out the imbedded material, exposes new abrasive grains and may actually cut some of the grains to give a sharper cut.

Of course shaping the wheel by dressing also sharpens it !

I've recently taken to using the multipoint dressers on my bench grinder as it is much easier to get a good flat surface than using a star point dresser. A single point diamond dresser should be reserved for situations where it is guided mechanically to get the desired surface. By hand you will inevitably get grooves. Remember you should be taking exceedingly small cuts with a diamond dresser - fractions of a thou at a time for dressing, for shaping you can be a bit more agressive but not much if the diamond is to survive long.

AWEM

In message , Peter Fairbrother writes

On a standard simple bench grinder - as used in most home workshops - you should not need to dress the flat face (side) of the wheel - you should not be grinding anything on it in the first place..

The area used for grinding on that type of grinder should be the periphery of the wheel.

Such wheels are not designed to be used for grinding on the side.

Too much pressure on the side of a revolving wheel can cause the wheel to burst - especially if there is a "groove" worn into the side caused by constant abuse.

I know that the side of a wheel is a good place to generate a "flat" surface on a tool but having seen one wheel burst I don't want to see another!

Sadly, perhaps because of its simplicity, the bench grinder is one of the machine tools that is not treated with the respect that it truly deserves in use..

Regards,

When I was at School the only machine tool they wouldn't let us use was the grinding wheel because of the danger if it 'bursts' and because misuse causes that to happen. Even the technicians had to take a special course and hold a certificate before they could use one! It's a long time ago, but I seem to remember being told that whilst you shouldn't use the side of most wheels, some are made specifically for that use? I also seem to remember being told that dressing a wheel is part of the safety procedure and that grinding soft metal is dangerous as the metal particles that clog the stone can stress it when they get hot and expand.

Scrim

That would just be grinding wheel regs, which is more to do with mounting wheels. This is the most critical part. I've got that cert, as it helped get the odd job now and then.

I do a lot of commercial cylindrical grinding, and often changing wheels, but what we have found is that these days a very good quality wheel rarely needs balancing. Ringing wheels is still a vital operation though.

Always use the side of the wheel in cylindrical work, there's now other way to grind to a shoulder ;) We dress (undercut) the side usually to create a narrow ridge though.

On offhand work I still do but around the periphery of the wheel, take for exampe drill point thinning. You have to used part of the side.

Wayne...