Drilling Itty Bitty Holes

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shred

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One day at the hobby store I ran across some small tubing benders-- basically a tightly coiled spring that acted as a support for the tube you wanted bent-- stick it in the spring and bend away. Not sure how well they work, but something similar may be the ticket.

Somebody around here periodically sells scrap graphite from EDM electrodes that's probably the same stuff, though I've never worked with it-- it tends to be in the form of flat plates and not piston-like shapes.
 
Anyone out there well versed in drilling small holes with big equipment? We are talking about #80 (.0135") in 6061 about .125" deep. The bits are obviously very small, and I believe I could break one of them by just by some harsh thought. I do have a finger chuck, and will utilize it. I will be doing this on the lathe (13x40).

Any tips? Wisdom? Warnings? Laughter?
 
I thought someone just post a video of drilling small holes.

But he was using a small lathe.

Hal
 
Here you go.

[ame]http://www.youtube.com/watch?v=q6-4oyIoku4&NR=1[/ame]

John
 
A lathe that size will never get up to the speed you need for a drill that small.

I have my Unimat permanently set up for doing work that size. Lacking such, see if you can mount a Dremel on your toolpost.

The plastic nose on the modern Dremel unscrews. Make a matching thread in a chunk of 1/2" aluminum and screw the Dremel into that. Attach to cross slide via whatever method fits your available tooling.

Another approach is to buy one of the Dremel router attachments and cannibalize the tool holder from it to provide a means of holding the (somewhat awkwardly shaped) tool.
 
I know exactly what you mean Marv.
I don't stand a chance on my lathe with a top speed of only 2K.
I used to have a PCB drill that got up to 25K and that only just managed, by taking it very carefully, to drill 4 thou holes.
I have a load of these very small drills but can't use them, touch on and they just break. Can't get up to the speeds required to make them rigid enough for drilling.
Maybe a chuck on my turbine might do it.

John
 
It can be done on your lathe, but it might be the deepest .125 hole you've
ever drilled.

At the lathe's top speed 6061 is going to wad up on that little drill bit like
bubble gum. Pecking .020" at a time and cleaning the bit off after every
peck will get it there. If your tail stock is not dead nuts on center in both
the X and Y axis it's a no win game. If you can find a local source for it
a good dose of Tap Magic Aluminum will greatly improve the chances of a
positive outcome. That is a personal opinion, but it does work very well
for me, on all soft metals.

What I'd like to know is just how they MAKE a .0135 drill bit!

Rick
 
Thanks for the input guys. I really figured the RPM, or lack there of, would be a big hurdle.

Rick, I have thought about the manufacturing process required to make a drill bit that small myself, and wonder the same thing! And just how do you clean a .0135" drill bit? :shock: If I sneeze on that thing, it'll snap right of!

The Dremel tool mounted on the tool post sounds like a good option, so I guess I'll be going that route. I don't know if I'll have the luck doing it with the tailstock.

I hope I can get them done without having to order more bits! :? I'll let you guys know how it turns out, or how many bits I go through before giving up. :wink:
 
I did some #70-ish holes (smaller than 70, but probably not #80-small) at 10K RPM on my Taig.. pecking all the way it came out ok-- the biggest hassle was finding a chuck that would actually hold a #70.

The cheepy carbide PCB bit sets from Harbor Freight snap at the slightest sideways glance, but I've had them do ok if you can keep the feed and speed in the right range and drive them exactly straight.
 
I did the math here.
A HSS drill bit with a 118 degree tip in aluminum should be run at
at a speed of 200 to 300 Feet Per Minute surface speed.
Aiming for the middle of that rage it works out to 73,461RPM
IF you have a machine that will spin a bit that fast please give me enough
prior notice to leave the area before you turn it on!!!!! LOL

Rick
 
rake60 said:
I did the math here.
A HSS drill bit with a 118 degree tip in aluminum should be run at
at a speed of 200 to 300 Feet Per Minute surface speed.
Aiming for the middle of that rage it works out to 73,461RPM
IF you have a machine that will spin a bit that fast please give me enough
prior notice to leave the area before you turn it on!!!!! LOL

Rick

I wonder if I will be okay if the bit is only turning 73,458 RPM? :lol: No need in worrying about turning the bits too fast. :roll:

I am with you, I think I wouldn't be within a few hundred yards of something spinning that fast! Wow!!
 
What you really need is a Cameron micro drill press

http://www.cameronmicrodrillpress.com/

but they're very expensive and only go up to 30K rpm. (However, I've seen them used at Westec to (manually) drill holes in the several thousandths range.)

I've often wondered if one could get a precise, tight spindle from some source (die grinder, dental equipment, junked watchmaker's lathe) and mount it in the tailstock and drive it with an externally mounted trim router and a belt. Use a router speed control to vary the speed.
 
I have a total of eight holes to drill, each being about .125" deep. The Cameron machine would be the cat's meow in this case, but I am afraid to guess what one of those things cost! :shock:

The pin vise trick that Bog shared looks like it may work, but my lathe will only turn 2000 RPMs. I don't think that will be near fast enough to make it happen with that method. May make that plan B or C.
 
one the great ME authors of yesteryear, don't immediately recall which one, successfully argued (to me anyway) that the need for these super high speeds for the very tiny drills is hogwash. I cant' remember the exact argument, something along the lines of as the speed goes up the downfeed would also have to go up - both trending toward infinity as the drill size gets smaller and smaller. obviously at some point a practical limit is reached - if we did have a ceramic bearing spindle going at 70k, you might that it didn't do much more for you than something at say 20k or even 10

The author i believe argued that there was a diminishing return as you got above a few thousand rpm

Now, I use a dumore speeder which is going at 25k, so I'm not adverse to speed. The point of the above isn't that speed won't work, but that you don't' need speed to do a good job. The critical thing is that you don't exceed a very tiny chip load - speed is sort of built in protection in that regard. The other way to get there is sensitive equipment where you can feel the drill.

here's a hand little device for achieving this - its a counter balance drill press table. you tape or otherwise fix the work to the table and the table raises the work into the drill. to prove the point i drilled a very small hole (90 iirc) using a 18" buffalo drill - that sounded boastful - wasn't meant that way, only that if the set up is sensitive enough, you can easily drill small holes at, relatively speaking, slow speeds (albeit it wasn't .125 deep!)


here's the table, its from a HSM article years ago

sensitivedrilltable.jpg
 
Wareagle,
I am having the same problems as you. I need to make six gas jets for experimentation for gas burners on flamelicker engines.
The hole size required is 0.006", I can get down to 0.012" using the pin chuck method, but anything smaller I haven't been able to achieve. Shakey hands I suppose.
I suppose I will have to take the easy way out and buy the gas jets and machine around the holes to get to where I want.

John
 
Bog, you are definitely punching out smaller holes than I am. I think that I am going to try the Dremel tool on the tool post idea, and may even see about using the pin vise if that doesn't work. I can get around 5000 RPM on my milling machine, so I may see about drilling them on it.

One thing is for sure, I am glad I don't have to do these often (though I haven't tried the first one yet). If I did, as was suggested I would buy or build dedicated equipment for the task.

In your situation, why couldn't you utilize your air turbine to drill the holes? The only thing I could see as a possible problem is there being too much runout (thrust) on the shaft.

The ideas I try I will post with the results. It will probably be the end of next week before I dive into this task.
 
Wareagle,
It seems so funny, this morning my mate came round clutched in his filthy hands, a load more tubes that they use on high precision spark eroding machines. Brass and tungsten, 1ft long and the largest tube diameter is about 3/32", the smallest 1/32"

tubes1.jpg


tubes2.jpg


I haven't measured the hole sizes yet but they definitely look like they will make some prototype jets. The middle sized brass ones actually have four holes thru them, but not round, sort of crescent shaped.

I mentioned about using the turbine, but only as a joke. But a slightly different design just might work very well. As I mentioned, I used to have a PCB drill, but got rid of it a few years ago, the only problem with it is that it wouldn't be able to drill up the centre of a rod as it looked like a very squat pedestal drill.

Very happy John
 
Bog, it looks like you made a pretty great score there! All of the pieces a foot long, you'll have enough jets to last several lifetimes!!
 
That little "peace" sign looking one will make a great flywheel.

:lol: :lol: :lol:
 

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