The Importance of Wheel-dressing when Surface Grinding is Revealed

[olderdan]

Hi Brendon
Well you asked for comments so here is mine.
That was an in depth analysis of wheel dressing, I have a few thoughts on this as I have spent over 30 years in the grinding shop, universal / cyl and form grinding gears and all sorts of forms needed in punch and die sets for the sintered metal industry.
Firstly brass is to me an odd choice for a test as soft metals do not lend themselves well to the grinding process unless you have a specific wheel grade usually silicone carbide green or black.
Surprisingly to some these wheels are also chosen for grinding carbide because they break down quickly to prevent clogging, this can also be dangerous as the embedded particles heat up and can cause wheel fractures, this can be reduced by a coolant flood.
As for wheels going out of balance on start up this is not something I have ever encountered and would suggest that it is not securely mounted to begin with, what you describe is more likely moving on start up torque and becoming eccentric on is mounting. Our form grinders had only optical dividing heads to work with requiring D/M/S setting at every index (a minefield for errors on a part worth thousands).
The safe way was to stop the wheel, index and see if you were in the right place before starting up again, we did this hundreds of times a day and never had a wheel go out of balance.
Same thing with universal grinding where changing from external to internal and back again requires the machine to be stopped, obviously this required a wheel dress but no out of balance was ever experienced and we are talking twelve inch wheels.

NB I wrote all the above before I read your latest post, you obviously know a fair bit about machine grinding so it seems you have narrowed down the problem already to wheel mounting issues.
All our machines were Jones & Shipman and the wheel flanges were taper mounted to the spindle, this allowed wheel changes without loss of truness as long as we left them on the hubs. As for coolant retention just let the wheels run dry before stopping and if you have soggy card washers it means something is not tight enough.