Drilling to depth?

[tornitore45]

How does the chip evacuation happen near the end, with collars or sleeves around the drill ?

Usually, on a deep hole, you retract the bit often to clear the chips, as the collar get close to the hole mouth you clean out before the flutes pack and then the last 1 or 2 diameters depth can pack the chip in the flute before reaching the hole mouth.

[GlennW]

How does the chip evacuation happen near the end, with collars or sleeves around the drill ?

Usually, on a deep hole, you retract the bit often to clear the chips, as the collar get close to the hole mouth you clean out before the flutes pack and then the last 1 or 2 diameters depth can pack the chip in the flute before reaching the hole mouth.

Counter bore the bushing a bit so the chips have somewhere to go.

[spro]

I know Dianne said the depth stop was unreliable ( pain to unlock and reset ) but it is still a quill stop. One thing, is that they are at least face milled. That means sleeves of appropriate ratio could be stacked within the stop. no matter where it is. The sleeves were exact tubes but are slit or milled open to fit the depth stop. Half turn and they don't fall out.

[Kimball McGinley]

I often use pieces of telescoping brass tube; the stuff with .014" walls. I kink or smash it a little to stay on the drill if needed.

[Bentworker]

I’m not on the sleeve or collar bandwagon with something as small as a #50.

A little over a month ago I made a tool that had 24 #56 holes drilled in it, with a wall thickness between the holes of about .018”

Personally I found when drilling that small I had the spindle speed cranked to ludicrous speed, and I had nearly no feel on the quill. I don’t get how a collar could be of any use on a drill that is .046” ish in diameter in a standard milling machine. It might be a little better with a .070” drill but I don’t get how you could stop reliably without breakage. A mini drill press yes... but I just don’t have a light enough touch for the quill on the mill.

I had quite a bit of depth tolerance on my project, .030 ish. I still didn’t want to over travel, so I ran the quill stop all the way to the bottom, then raised the knee to desired depth.

[spro]

I read your sense. This topic is approached by different attitudes, machines on hand. Solution for one may not be the same at one particular time but I enjoy knowing more than I did. Ideally, Dianne would have a sensitive, high speed drill press for just these holes. Cannot be and still the depth needs be exact. There is the adjustable quill depth "gage". semi collars are stacked like gage blocks.
There is more to the OP than I understood and we may not be dealing with a flat plane here. In that case, sleeves of correct length is the answer.
Really though, inexpensive digital caliper mounted to the head and quill was all that was needed. That was already suggested.

[GlennW]

I don’t get how a collar could be of any use on a drill that is .046” ish in diameter in a standard milling machine.

It's not a standard milling machine, it's being done in a drill press with a barely functional quill stop.

[Bill Shields]

stay away from the collar idea for this application....asking for trouble with chips and drill breakage.

I touch the drill, then crank up the table the desired amount.

made quite a few pumps this way....

I would not suggest you do this on a drill press, since hole position is rather touchy and a 'center pop' may not be where you want and end up breaking through into another passage.

best if you use a mill and crank dials (if no DRO) from a set 0,0 so that you know where you are

[pete]

If I recall correctly you don't have a mill Dianne, so ya gotta use what you have. My guess is it's a model part with holes that size correct? If that's right then the pump isn't real large. Do you have a lathe milling attachment? If so your lathe would be the machine to use if you don't have a mill. Accurate movements can be checked and set in all three axis's with the standard 1" travel shop indicator if needed. Getting your holes spot drilled or second best center drilled is going to be important for location accuracy as well. So again I doubt the usual off shore bench or floor drill press would be up to that either. Before dros were invented they coordinate jig bored a whole hell of a lot of holes to well under a 10th for location accuracy using equipment not all that much better than a decent dial indicator and setting rods much like micrometer setting rods. With some time and a bit of thought and patience, and a lathe milling attachment I'd think you could get well under .002" for location and hole depths. It wouldn't be a very fast method, but it should be accurate if the job is set up correctly. Quite accurate edge finding and drill tip to part location can be done to under 1/2 a thou with little more than a bucks worth of Zig-Zag cigarrette rolling papers.

[Bill Shields]

how about an XY table on a drill press?

[SteveM]

The Cameron Micro Drill uses a dial indicator to measure depth:


Maybe you could rig something up on your quill stop to measure distance with a long-travel indicator?

Steve

[johnfreese]

It is tough to make a recommendation when the type of machine is unknown. A technique I have used both on the mill or drill press: I make a gauge block whose height is equal to hole depth. I have used adjustable parallels, bits of steel with the right dimension, or milled to size blocks. I lower the drill until it touches the work, then adjust the stop nut until it just touches my gauge block. If the drill slips in the chuck I have to reset the stop nut.