[sabastion]

I know this is probably a stupid question (round end mills and sharp inside corners)

can these mills cut sharp corner (L) pockets and holes in sheet-metal for computer case panels or console panels or am i going to have to contract a plasma cutter?

[eartaker]

There is no way for a endmill to cut a square inside corner.... the corner will have a radius equal to the size of endmill. You will need a jig saw or plasma to do what you want.

[Geof]

Square cornered pockets are approaching impossible.

Square holes are feasible: Google "rotary broaching"

[Atael]

Since we're talking about sheet metal here I'd avoid any mills or lathes for it, depending on the type of pocket you want made (the size of it) I'd recommend either a punch press or a laser to do those for you, the punch press is significantly cheaper to use for mass production, but the laser will do a better job at shaping the pockets at a significantly higher cost, its your choice to decide which one you preffer.

[tkubic]

wire edm.....lol, just to throw another, rather rediculous option at ya :P

[bladehunter]

For one offs you could always just clean the corners up with a file.

[rwskinner]

I've done some pretty good triangles before but it wasn't on purpose. Loose gibs and a way too high feedrate and it had lots of sharp corners

[roninB4]

You can relieve the corners with an end mill, this is done all the time with square pockets in thicker material. If this is in sheet metal it will require solid clamping to avoid vibrating the sheet metal. The number, size, and proportions of the square cut outs may affect whether this is a good choice or not. For prototype work a simple die/punch like a shim punch is often employed. If you're going to run production numbers then a punch press might be a better route. You haven't provided enough information to give you a better answer.

[sabastion]

thanks for your replies guys...question pretty much answered
Richard