drilling tiny holes

[MattBower]

Do any of you have any tips for drilling tiny holes -- like .032"? I don't have a micro drill press or a lathe, and my regular drill press has too much run-out for the tiny bits. Best idea I've had so far is to put the bit in my flex shaft tool, mount it on my drill press table with the bit vertical, mount the work in the drill press chuck, and lower it -- with the press turned off, of course -- onto the spinning bit. I don't know if the flex shaft is precise enough, but maybe.

Any better ideas?

[Dragons lair]

Might work IF ya can clamp the tool perfectly vertical. If ya were southwest Va ya could drop by and use the lathe. Am always drilling out mig tips.
Ken.

[arftist]

Tiny drill but want to spin very fast with very light pressure. What material are you drilling?

[MattBower]

Brass. The bits are carbide.

The high speed thing is what got me thinking about the flex shaft. MIne's air powered. Spins pretty fast. They make drill presses for Dremels, but I don't have a Dremel and my air powered version wouldn't fit. (Plus I'd rather not spend the money if I don't have to.)

[MattBower]

Might work IF ya can clamp the tool perfectly vertical. If ya were southwest Va ya could drop by and use the lathe. Am always drilling out mig tips.
Ken.

Kind offer, Ken. If I were closer, I'd take you up on it.

[bigfootnampa]

I would likely just drill those with my flex shaft tool hand held. How perfectly vertical do you hope to get them? Because tiny drills like that are pretty flexible... usually I would use a jewelers type bit with a very short tip on a 1/8" shank. How many holes? Because I might just use my flex shaft or dremel tool sliding in a two sided angle guide for just a few that needed precision.

[BIGGUNDOCTOR]

HSS bits will flex some, but solid carbide needs absolute rigidity. I did a set up at work to do .031" with carbide, and we did it in the mill with my micro handfeed chuck in the quill. You need to be careful with brass, as it has a tendency to grab the bit sucking it in. With larger bits I grind a vertical flat on the cutting edge to prevent this from happening.

Can you isolate where the excessive runout in the drill pres is from? Is it the chuck, arbor, spindle, Mose taper-if it has one? If it is the chuck, or chuck arbor you can replace it with a better one. Having runout in the drill press isn't good for any job.

[MattBower]

I would likely just drill those with my flex shaft tool hand held. How perfectly vertical do you hope to get them? Because tiny drills like that are pretty flexible... usually I would use a jewelers type bit with a very short tip on a 1/8" shank. How many holes? Because I might just use my flex shaft or dremel tool sliding in a two sided angle guide for just a few that needed precision.

Only a couple, hopefully. I might do a little better with HSS bits. I just happened to see a set of the carbide bits at HF and grabbed them.

I'll play with this and see what I can come up with.

[pkrankow]

I think I know what your setup looks like given the HF source.

Consider using a bungee to tie the drill spindle to the support tube, this will remove slop (remember we are not turning it on, it is a carriage)

Use a plumb bob or long straight wire to verify that the spindle is traveling true to the table, this may not work if it doesn't.

Then use the plumb bob or long straight wire to verify that the air tool is in line with the travel of the spindle.

After that it is just clamping the work piece accurately and feeding carefully. Pecking is probably best with the tiny bit.

I think I have the same set of tools, but have never tried this.

Phil

[IronPuppet]

Hi there, I do a lot of scratch building for my HO train layout. With working on a 1/87 scale means I drill lots of small holes in a variety of materials with drills as small as a number 80 or .0185". In my experience the small drills are fragile and break easy and even a Dermal with a drill chuck attachment (I have one) has to much inertia and if the drill bit jambs because you feed it too fast for a split second, the bits snap off and then you now have the compound problem of a broken bit stuck in your future hole. The best way to drill them small holes is by hand with a Pin Vice.

The top of the pin vice revolves and goes in the palm of your hand while your fingers do the twisting. The one I show here is the kind I like the best because it will handle any size shaft with it's four sizes (two double ended mandrills) and the mandril you are not using stores in the handle. The one I got was less than ten bucks.

You might think that this method would take a long time, but you would be wrong. Because of the smallness of the bit, work goes quite fast and having your hands right on the tools lets you get the feel of how much pressure to put on the bit and how good the cut is coming along. It works well and with care and attention you can get a lot of use from one bit.

I bought another kind of pin vice with a ball at the end of the handle because I thought it would be better, but I found it clumsy to use. The ball gets in the way too often and I find I don't need that much pressure anyway on the smaller holes, so I keep the ball end pin vice for the larger bits. The mandrel doesn't store inside the tool either and I keep losing track of the one not in use.


In any case, check out your local hobby shop and pick yourself up a pin vice. You won't regret it. You might think about getting a case of the really small micro drills while you are there.

Christopher

[MattBower]

I actually thought about a pin vise, but I've never used one and I didn't know how well it'd work on, say, ~1/4" of brass.

BGD, I don't know the source of the run-out. I probably ought to track that down. I just need to pick up a dial indicator.(I assume that'd be the right tool for the job? In addition to being very thin on the precision measurement tool front, I'm very far from a machinist.)

[arftist]

A small cheap benchtop wood working drill press is all you need to do this job well. Use the highest spindle speed, clamp the work, use the carbide bits, and drill with very very light feed pressure.

[Old N Rusty]

My Dewalt battry drill chuck closes up tight enough to chuck a pin and can be S....L.....O.....W

[BIGGUNDOCTOR]

A dial indicator will do the job. You will also need a way to hold the indicator rigid. The way I would do it is this way. pop the chuck out of the spindle ( if it has a Morse taper) and check the bore for runout with the quill locked, and moving the drive belts by hand. If that has runout, then you are pretty much done unless you can get it re machined true. If it is good then replace the arbor minus the chuck (if removable), and test that. Sometimes they get bent, sometimes they are just made wrong. If that is good, then it is just the chuck being off. You can check the chuck by putting a dowel pin, or some other really round straight item in it to test. If all that checks out good, then loosen the quill lock, and push the quill side to side,and front to back to check for slop. I have used loose drill presses by snugging the quill lock some to take up the slop. Not perfect, but it got the job done. Also with a tiny bit like that make sue you use a center drill first to get it started correctly.

[MattBower]

Well I re-squared my press table as close as I could get it, set the spindle speed as high as it can go, and tried some test cuts on scrap sheet steel, just gently pecking away in tiny little bites. 0.04-something" went OK. 0.01-something" broke almost immediately. (That one was so tiny I was having a hard time telling when it was making contact.) I'm not sure I'm up for rigging up the air tool to try tonight.

[BIGGUNDOCTOR]

At work I use my hand feed drill chuck. It has a max cap. of 1/16" (1.5mm) and works great for these tiny bits. It only has about 3/4-1" of stroke, so you get it close then lock the quill in position. After that you feed the bit by hand pressure alone. Mine has the Albrecht chuck, so it can be pricey new, but there should be some used ones floating around.

[MattBower]

More sensitivity would help. That may be why the little one broke -- the drill press may be a little too clumsy.

[Spears]

In the machining world new and improved with CNC, high spindle RPM, and controlled feed rates, yes sir! Carbide is state of the art. But in the freehand environment with a workpiece as soft as brass, there would be no reason to use carbide. Good quality high speed steel drill bits will be more forgiving perhaps even drilling holes slightly dull with lubrication and successful chip eject. Carbide that small with the slightest bit of loading up is going to snap. I use the high speed black oxide coated bit versus the bright finish if I have a choice. Good luck with those tiny holes. Spears.

[MattBower]

Thanks. Yeah, I know carbide isn't ideal, but it's what I had. I Will get a few HSS bits.

[LordVen]

blck and decker no 40 drill press stand

[MattBower]

I'm not sure what that is, and Google doesn't tell me -- at least not up front.

[MattBower]

I'm not sure what that is, and Google isn't helping me much.

[MattBower]

So my pin vise arrived from McMaster-Carr today, along with a few tiny HSS bits. The vise maker is General Tools. Once I figured out that there was a second collet in the handle (I was starting to get slightly agitated that the first collet wouldn't grip a #75 bit, when the package clearly said 0"-1/8"), I inserted the 0" collet, stuck a #75 in it, and tightened it down. It gripped the thing fine -- but I couldn't seem to get it to hold the bit straight in line with the long axis of the tool! At first I assumed my fat fingers that were the problem, but I held the collet up to the light and I can clearly see with the naked eye that one of the kerfs used to make the jaws drifts off at an angle from the center axis of the collet. So yeah, that's not gonna work.

Grrr. I bet this wouldn't be a problem if I'd paid a little more for a Starrett vise. I didn't think about it at the time. McMaster is convenient and fast, and I was buying the bits from them anyway.

[BIGGUNDOCTOR]

When using a drill press for tiny holes , grab the hub, not the end of the handle for feeding the bit. By palming the hub in the center you greatly reduce the torque that you can produce. Grab it similarly as you would a round doorknob.

I believe the stand mentioned above is one that you put a power hand drill into to convert it to a drill press.

I have hand fed carbide drills at work in the Vertical mills. Once they get down to .0625" I put my hand feed chuck into the spindle.

As soft as brass is it can sometimes suck a bit into itself. I have had this happen on occasion, I have some bits that I have ground the cutting edge to a small flat. By having it flat it produces more of a scraping action rather than digging in. With your small bit,you should be able to keep it from grabbing , but if it does, you may want to try hitting the edge with a fine stone to flatten it some-maybe a stroke or two at the most. Keep the chips cleared, so they don't pack into the hole. Just use a steady repetition of pecks to get through. The middle shouldn't be much problem other than dealing with the chips, but as you break out the backside it may snag, and snap.

Good luck.

[MattBower]

Well I got a replacement pin vise from McMaster (they told me to just throw away the first one, but I think I'll use it as a handle for needle files), and just drilled a #70 hole through a nickel silver key for a car I no longer own. Took a while, but I think this'll do just fine for my current purposes. Thanks for the advice, folks.