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03-23-2008, 02:46 PM #1
Question- drilling very tiny holes
How would you do the following. ?
Imagine you have a brass, socket head cap screw 1/2 inch long with a 10-32 thread. You have drilled a #52 hole down the middle the entire length. The bottom of the socket hole has a radius so it does not have a flat bottom. NOW, you want to drill two .006 holes on either side of the #52 hole that are parallel to the #52 hole and extend from inside the cap hole to the bottom of the screw.
How would you drill the holes?
03-23-2008, 04:25 PM #2
It would be nice to know the actual dimensions of the piece and how many you intend to make. Also what are you going to use for a .006" diameter drill and how deep are Those holes.
I'd hope you could do a better job of getting the .006" holes in a better center line up than the one you are holding. *Grin
03-23-2008, 06:15 PM #3
Drilling small holes
I presume you have some .006" drills, one may not last. Put a piece of 1/4" brass or aluminium in the lathe chuck and drill and tap it 10 - 32. you have to remove it to insert the screw and replace it in the chuck, thread out. now pack it off center the required offset or use a four jaw chuck. Get the dremel flex shaft attachment and make a holder for the end for your toolpost. if you use the dremel 3 jaw chuck they will go down to 0 The problem is that the dremel only spins at 32,000 and with a .006 drill the correct speed is 133,000 rpm for brass so you will be going a little slow. It's more like the correct speed for alloy steel. As the carrage is not sensitive enough for such a small drill you will have to build a sensitive hand feed for the operation. centerdrilling is needed to not have the drill wander, so you will need a center drill smaller than #1 I think I could do it with a sensitive feed on my setup. Hope this helps some. Peter
03-23-2008, 06:26 PM #4
Drill it from the bottom, not from the radius bottomed allen hole. Do it on a high speed drill press with an x-y table bolted to the drill press table
03-23-2008, 08:31 PM #5
Drilling tiny holes
I've just been out to my shop and have polished the knurls off my dremel flex shaft and reversed the block so that the slot is outboard in the holder and the flexshaft slides smoothly in the holder making a sensative drilling fixture. works smoothly and gently. would work nicely for your application. Peter
03-24-2008, 01:37 AM #6
Drilling a .006 hole through 1/2" of material will be an almost impossible task. That is equivalent to trying to put a 1/2" drill through 40" of material. You will twist the drill off long before you get through. Is this some sort of metering orifice? is so I would suggest drilling it about .030 and boring the end out for a watch
jewell to be burnished in.
03-24-2008, 02:56 AM #7
If it were steel, I'd agree with you, but being yellow brass I think it will go pretty well. I have drilled through nearly 1/2" of steel with an .008" drill in the past with hit or miss success on a Bridgeport. With a proper high speed sensitive drill press and drilling yellow brass this should be a cakewalk.
03-24-2008, 03:10 AM #8
Use a suitable endmill to create a flat for each hole so that the .006 drill can be started on perpendicular surface.
03-24-2008, 03:12 AM #9
Use a .005 drill and stone the flute larger on one side.
that will give you a oversize hole, and good chip relief.
Otherwise it will be a long road at that depth.
03-24-2008, 10:58 AM #10
If it's for metering........
.........drill such holes @ twice the desired diameter for all
but about 4 diameters of depth.......
then the rest of the way @ the desired diameter.
the flow of your substance should be from the small hole-side
to the double hole side, for valid flow results & resistance to plugging.
03-24-2008, 01:52 PM #11
Hmmm.... I would drill and tap a 10-32 hole in AL or Brass.... screw in the part in question.... move off center the prescribed amount...... Buy some .006 pivot drills as these have 3/4 cutting capability.....start drilling... if you are worried about breaking out on the radius then drill both holes to within .020 the end and finish with a drill in a pin vise. Not sure what you have in equpitment.... I seem to remember you having a Hauser M1 or something. I sure hope to hell you are going to TELL US how you did the job!
03-24-2008, 02:11 PM #12
Does Markusfu really mean 0.006 diameter? I am beginning to wonder.
03-24-2008, 02:55 PM #13
You seem to have had some experience in drilling small holes in brass. I would like to ask you a couple of questions.
Equipment: I have a Delta "Super-Hi" sensitive drill press with 80-J2 Albrecht chuch (0-5/16"), with 3 speeds up to 12,000 rpm, and an X-Y table mounted on it. I also have a small Cameron micro-drill with 15-J0 Albrecht (0-1/16") with speeds up to 30,000 rpm, but no X-Y table. Both chucks will hold a 0.006" drill (my really small drills all have a 0.039" shank), and both have essentially new bearings and very little runout (at least, I cannot measure any). The Delta drill weighs about 100 lbs. and the Cameron drill weighs about 10 lbs. Even so, both drill presses have fairly good "feel" when drilling a 0.010" hole in brass.
First question: Is it really advised to use a speed over 30,000 rpm (say, 100,000+ rpm) when drilling a 0.006" through hole in brass 1/16" thick? I would have peck drilled at about 12,000 rpm using the Delta drill press. I would think that "drill whip" would start to cause problems above 30,000 rpm (but these speeds are above my equipment's ability, so what do I know!).
Second question: What brand of DP would you/do you use to drill very small holes? I have hardly used the little Cameron DP, and prefer the Delta. I only work in brass, and occasionally nickel silver. Really would like to hear your thoughts on this!
Thank you very much for your reply.
03-24-2008, 03:23 PM #14
You're quill-feed is steady and responsive enough, (TO);
give you steady unifoem control of you're feed.
The higher speed gives more tollerance to inconsistant feeds,
and rough re-contact after pecking.
An example of an excellant feed is a "Good" Tree quill.
With neuteral quill-spring-tension,
and a well lubed and clean quill.
The stop is so far superior to the Bridgeport style quill-stop,
(THAT) you can litterally peck exactly as much as you advance the stop each peck.
I wouldn't hesitate to do a .006" hole with a good Tree
03-24-2008, 04:47 PM #15
drilling small holes
Several friends say it is impossible but I did the first two small holes starting from the bottom of the screw using a .006" twist drill using the servo sensitive drill press and I held the screw in a small vise that was not fixed solid to the table. Yes it took a bit of time , with constant cleaning of the hole with a watchmaker's feola air blower. I was OK with the first .005" hole, but the second wondered a bit too much for my liking. .......................................OOPS--I just remeasured the little twist drill...... I'm so sorry!!!!! The hole is not .006, it is .015" .
I'm going to try again, but I will try it on the Lietz jig borer . Someone asked what it is going to be used for. It will be part of the mechanism for a miniature pressure oil gun. Air will be forced( hopefully) through the small holes and the oil will squirt out a .052" piece of tubing that will be in the larger hole.
Thanks for all the ideas and opinions- I may end up using some of them.
Todd- I'm not sure if I would have room for the jewel idea but it may be worth a try also
Last edited by Markusfu; 03-24-2008 at 05:27 PM. Reason: spelling error
03-24-2008, 05:08 PM #16
.015 from .006 is a big difference! ....... I can see .015 drills
there's an argument to be made that you do not need to go anywhere near the theoretical speed, in fact theoretical speeds are all about maximizing efficiency and removal rates - if you had enough patience and a sensitive enough device to not over load the drill, you could do it at 50 rpm - not far fetch either, ever use a pin vice to drill a hole? I can't remember the source, but remember reading a well reasoned account on why with there's very small drills there's such a rapidly diminishing return trying to approach theoretical speeds, something to do with the impossibility the feed rate going anywhere close to be the right compliment to the speed. not that the speed is bad, just that it doesn't give a as big an advantage as you might think of you are just doing the odd one.
anyway, imo the critical thing is very sensitive equipment so you can feel the force on the bit. I've got a variety of tackle to do small holes including a sensitive drill press I made, but the best I've come up with is this sensitive drill table - it raises the work up into the drill. I mount a dumore drill speeder (15k) in an 18" buffalo and use this little, balance, smooth table. You don't need the speeder, so long as you have a chuck small enough and with minimal run out
sensitive drill press table
drill speeder setup (turn off the breaker if you emulate this set up!)
gratuitous pic of my homemade sensitive drill
03-24-2008, 05:13 PM #17
03-24-2008, 05:25 PM #18
Mcgyver- I like your sensitive table idea if one's downfeed quill doesn't have the sensitive touch!
03-24-2008, 05:34 PM #19
yeah that was a funny setup, it sort of grew as i puzzled on it. no bubble gum or hair pins though the nic is just from friends, I have never made hang glider out of tent polls and long underwear
Markus, can't take credit, it appear in one the "Projects" books that Village press puts out (HSM article reprints) A good little project that really works.