Hi

these are not R8, they are a 3/4" parallel shank, 1.38" long, at the end of the shank there is a 1.5" ring that locates the tool axially on the spindle nose - this is the secret to their repeatability for tool height.

I am using R8 now and they are not bad but do vary as not all made by same maker/machine etc - on the R8 the only location is the taper for both axial and radial location. The parallel shank system has the ring for axial and the R8 collet for radial location, as the collet is tightened it draws the shank into the spindle a little and snugs the ring against the spindle nose.

I have been looking at my tools and youtube videos etc and it seems ER20 is the best all round size, especially as i mostly play sub 1/2" tooling. The body of ER32 chucks is bulky and blocks the access for coolant when using smaller tooling.

I have been emailing the guy in China and am in the process of getting a price for 18 ER20's, 2 ER32's and a drill chuck :)