pastera
NES Member
Not talking about the endmillThat’s an imprecise generalization.
This is better: Never put an end mill with a taper in a drill chuck.
None of my end mills have a taper, they all have a cylindrical shank, including the ones that came with the jig.
It's the drill chuck itself that is mounted on a taper.
I've used an endmill to flatten the bottom of a drilled hole but you need to be careful not to damage the chuck jaws on the hardened endmill (drill shanks are soft)I would say, never put an end mill in a drill of any sort, including a drill press
You can tell it's completely the wrong tool the way they run - the chatter. And as stated, they can & will eject the chuck. But regardless they don't do a very good job anyway, extremely inaccurate. Even a heavy duty sorta home shop drill press, that might cost $1000 like a cheap mill, isn't rigid that way.
The only time I've seen this end-mill-in-drill-press practice condoned is with 80% lowers - basically a way to market the products to folks who lack the patience to use the tools they can afford (ie a file if it's a polymer pistol, possibly by first drilling out the blocker for the spring by stepping bits up to get a headstart)..
A router jig is sane though - a router is meant to work like that. A mill that happens to use a drill chuck, sure that's even better.