What type bit do I need?

[econoaddict]

I am drawing a blank..........
I need to make 3/8" diameter holes, 1/8" deep in aluminum.
Not going all the way through, they must have a flat bottom.
What is the bit called I need?

 

[jjjrmx5]

You doing this with a hand drill, drill press, 5 axis mill, water cooled CNC mill, metal lathe/drill machine or what??

Big differences.

 

[lwlobo]

I think you're looking for an end mill.

I strongly suggest not doing this by hand, a drill press is minimum and mill is reccomended.

 

[metaleltr]

iff all you have is a hand drill you may be able to accomplish this with a forestner bit, it wont be easy and may destroy the bit, use lots of wd 40

 

[fnieto]

Bullet bits cut a flat bottom, but leave a small pilot point in the center.

 

[econoaddict]

I have a drill press to do this.

 

[rlitman]

You could try a 4-flute end mill, but be sure to clamp down whatever you are drilling.

 

[kenburkholz]

The bit you need, is an end mill, just be sure it is a center cutting bit. Also very important is a very secure hold down. Ken.

 

[Givl Reggin]

Depending on the accuracy you need, I think the steps are after you do the lay out are;

1) Center Punch
2) Center Drill
3) Twist Drill
4) End Mill
5) Reamer

 

[larry_g]

Assuming you have no pilot hole then a center cutting end mill. If you have a through hole then you may be thinking of a spot facing tool or a counter bore.

I would give Mr Riggin a bye on this as I think he miss read the question..

lg
no neat sig line

 

[Strouty]

Forstner bit would probably work in aluminum without destroying it. I would use a drill press though.

 

[augustus]

I use my forstner bits all the time, on wood, at least with my set you don't an absolutely flat bottom, they leave a little cone from the pilot.

 

[Thunderbisciut]

I've put my cheap forstner bits through plenty of aluminum without issue. Nice and slow worked for me.

 

[Stuey]

Adjustable counterbore with interchangeable pilots, but without a pilot.

Or an endmill.

 

[econoaddict]

Thanks for all the input.
I am thinking the bullet bits will do exactly what I am looking for on this project.

 

[A_Pmech]

Without a milling machine or sturdy drill press, you need a way to establish location first. If there's a thru hole in the center you can use a piloted spot facer with the appropriate pilot.

Without a thru hole to guide a flat bottomed tool, I would start the hole with a 3/8" 135 degree twist drill about .05" deep and finish it with a 3/8" end cutting endmill or a 3/8" flat bottomed drill: