Split Point Drill sharpening

[Okapi]

I'm not totally in accordance with Tony's explanation, they are grinding wheels made as cups(or others for 45° use) for grinding on the lateral part, all makers of grinding wheels explain that you never use a wheel made for perpendicular use as a lateral use, you find it that on makers like Norton, I've only the french catalogue from Norton but you can found the same in english on the web easily.
They explain to never use on the side a wheel cup or another when the thickness is less than 10% of the diameter, then 30mm. for a 300mm. wheel etc…

[tonyfoale]

I'm not totally in accordance with Tony's explanation, ....

I didn't give any explanation, I asked a question which has not been answered yet.
WHY should I break the habit of a lifetime and stop tool sharpening on the side of flat wheels?
As advised I looked on Norton's site but the only relevant text that I could find was a list of DOs and DON'Ts. The DON'Ts said avoid the side but without explanation.
I have never been very good accepting DOs and DON'Ts as plain statements, but I will always consider an explanation. When someone tells me not to do something I expect that they will know WHY and be able to explain it to me. So far in this case the WHY is lacking.