Those of us with shaky hands and failing eyesight find it hard to reliably sharpen centre cutting, 4 flute, carbide end mills. Even with the ubiquitous Deckel clone D bit grinder, it is still difficult to see what you are doing so that you don't overgrind past the centre of the cutter. This simple modification gives me a little more confidence grinding this style of cutter, and yes, I know I mixed up the terms "primary relief" and "secondary relief"!
Check out an excellent tutorial on grinding milling cutters in general on Projects Down Under's channel ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-neupF0-UnPo.html
25 ноя 2022