Mill or drill??

[Paulc]

Have a .75 aluminum round, .5 inch long and it needs a .5 inch hole thru.
Better to drill or mill?

[EdK]

I would use a lathe to drill it or bore it depending on how accurate it needs to be.

Ed

[Highpower]

A drill will remove metal much faster than an end mill. Even though you CAN plunge cut a hole with a (center cutting) end mill, that's really not what they are designed for. And it's a lot easier to resharpen a drill than an end mill.

Like Ed said depending on your needs, drill slightly under size then bore or ream to your final dimension for an accurate round hole if that is what you need.

[Paulc]

After fooling with a Chinese boring bar set for half an hour and getting crappy results, I finished it with a 1/2 in drill in the lathe tail stock and the results were very good.
Did a second one by progressively drilling a larger hole after starting with a center drill and that went smoothly as well.

[Highpower]

(11-03-2019, 11:26 AM)Paulc Wrote: Did a second one by progressively drilling a larger hole after starting with a center drill and that went smoothly as well.

Not surprised with the Chinese boring bar results. Been there done that. When drilling my method is to use 3 drills. Center, pilot and finish. I measure the width of the chisel edge of my finish drill and use that as my pilot drill size.

[EdK]

(11-03-2019, 11:26 AM)Paulc Wrote: Did a second one by progressively drilling a larger hole after starting with a center drill and that went smoothly as well.

That's what I usually do if accuracy isn't that critical.

Ed

[Paulc]

In this case it was just two spacers for a shaft