I wanted to make a collet tray for my ER20 collets, so I drew these collet models to help me do it. I found that the measurements and standards vary a bit, so I actually came up with 3 different models. The inch model is based on the drawing I found on the MariTool website, the metric model is based on the drawing I found on AliExpress, and the measured model is based on my own caliper work with the set of DrillPro collets that I ordered from BangGood. All 3 models are based on the same 30deg nose and 8deg tail, because that specific was the same in both drawings (and I don't have an accurate way to measure that myself).
All three are slightly different, but the collets that I measured appear to be closer to the 'inch' drawing's dimensions. Still, I figured that I'd include all 3 in case you have a different experience.
My collets from BangGood also seem to all have a 10mm ID on the back side, so that's the size of the through hole that I added to these models. Your mileage may vary.
Drawn with DesignSpark Mechanical. RSDOC source file included.