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The diamond grain size D76 is an average of 0.076mm 76 microns and D107 is an average of 0.107mm 107 microns. This as you can imagine looks a lot finer than the diamond grain used in the dressing jig. You are correct the speed at which the diamond travels across the wheel is important and this is called the overlap factor. A conglomerate style dressing tool needs to travel farely fast and the overlap factor is normally based on diamond travel per wheel revolution. I will try to estimate the diamond size used in the pictures and update the thread. I will also try to source the dressing i describe. Incidentally you mention the depth of cut taken when dressing, i would recommend no more than 0.01 to 0.015 mm which would be difficult to measure.

[Grinding wheel grit size]

When dressing small grinding wheels that contain fine abrasive grit it is key to have the right size diamond grain in the dressing tool. The table below is an extract from something i have used for many years in relation to multi-point dressing tools very similar to the Tormek tool. The tool should only be 4 mm diameter with a carat content of 0.6 carats for this wheel size.

Grinding wheel grit size        Diamond Grain Size
320 - 600                                 D76
220 - 320                                 D107

Are the diamonds in the Tormek tool this fine?

I personally have problems with dressing using the jig and find it difficult to get a good dress on the Tormek, i am new to the Tormek grinding machine and very interested in the comments in this thread. I have tried using the cable ties and to some extent this as helped.

In the Vimeo video it looked like the SJ wheel was being dressed without water, is this the case? From my experience heat can be an issue but vibration is a bigger issue even at these lower wheel speeds being used. I believe the dressing process would benefit from a smaller diameter diamond dressing tool. This would reduce dressing pressure and the amount of heat being created in the dressing process. Less dressing pressure would result in a flatter wheel periphery as well. I am not sure if there is a diamond dresser available from Tormek with a smaller diameter.