(Drilling) Bottom Hole Depth

[Zero__]

Hi guys,

I'm trying to create a 1" deep hole in 1" thick aluminum. The top half of the hole is .3115 (bored out with an N drill, then reamed with a .3115" reamer). The bottom half of the hole is 1/4-20" tapped.

Because I'm predrilling then reaming a hole which is not a through hole, I have to be careful with my depths. So my question is this: if I create a Drilling operation with my N drill, and set the depth to "hole bottom" which is half inch deep, is the "just the tip" of the drill going to half inch deep, or does it take it down past the point to the cylindrical portion?

Second question: help me with this operation. I'm thinking I need to take the cylindrical depth down to .5", so that when I bring my reamer down to a .5" depth, it won't hit a conic of material it isn't supposed to deal with at the bottom portions of the hole. Does this sound correct?

[LibertyMachine]

To answer your first question:

If you have "Drill Tip through bottom" turned on, it will cut deeper than .50", and it will actually be .500" deep at the full diameter of the drill. With it turned off, the point will go to .500.

Second question:

If you are going in with a reamer, you do not want it hitting any material left from the drill point. You want to either use an endmill and interpolate it to be a flat-bottom, or go deeper with the drill

[Zero__]

See this is more than I already knew. You're saying that just checking "Drill Tip through Bottom" already does something. Even if I don't enter a break through depth, it's going farther down already than it would have.

So if I want the drill to go to the full depth of the drill bit and no further, I should select "Drill Tip Through Bottom" and leave the Break Through Depth at 0? I'll make certain my drill tip angles are correct!