Single vs double end end mills

[Inspector]

I didn't mean to say the won't work in a collet only that the plant I worked in used them in Weldon type holders and should have said without any damage to the end in the holder. It was a CNC plant and practices there would not be the same in home or small businesses running manual machines.

Pete

[toddalin]

So yesterday I needed an end mill and only the double ended bit was the right size. I looked at the bit and it said 9/16". So I pulled the 9/16" collet, and the bit slid in almost up to the "round" but would go no further.

Then I realized, while the end mill was 9/16", its "round" was 5/8" even though it doesn't appear to say this anywhere. A 5/8" collet, and the bit easily slides up onto the "round" for a firm grip and life is good.