retention knob

Does anyone out there know what retention knob (pull stud) is used on a Dynamyte DMV 4500 cnc vertical machining center year 1994, CAT-40 tool

I would suggest you take measurements from one of the ones you have and compare it to one of several sites like
- CT-40 Tool Shank
or
Rettention Knobs and Pull Studs for Machining Centers/Mills

and identify the critical dimensions for your retention knob.

If you do not have any...I cannot help you there.