darrin1200
Darrin
Sorry for the delay. Not sure if these were standard issue.@TorontoBuilder answered your question. But I have a question about your question. What is a 4C adapter? I suspect a typo or a name for something I call by a different name. Can you post a photo?
5C is a common collet style often used on lathes. You can buy 5C chucks from many sources.
It is MT4 taper on the outside, with chamfer on the inside to fit 4C.
Its pulled into the adapter with a drawbar.