Picture of Drill Small, Precise Holes.
This Instructable well help you drill a line or grid of holes with 1/400th of an inch (0.06mm) tolerances. Or so. The holes in this photo are 1/32" (0.8mm) across and 3/64" (1.2mm) apart, but the same technique can be used to drill even smaller or closer holes. And you can go bigger too, the same method will use to drill a grid of holes of just about any size.

It's not super difficult, but it does take the right equipment, attention to detail, and practice. I probably drilled 30-40 holes before I got the technique down well enough to get even spacing most of the time.

It's worth noting that this works best on soft material like plastic and wood. Harder materials like steel are a bit tricky since I don't center punch the holes which can cause the drill bit will to wander a bit.

Thanks to my brother Nick for giving me the nudge in the right direction to figure this one out.
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Step 1: Tools

Picture of Tools
Here's what you need:

  • Small drill press. The one shown is an adapter for a Dremel rotary tool (Dremel #212), plus a small keyless drill chuck for the same. (You can possibly use a full sized drill press, but I'm not sure you'll get as much accuracy, and getting a #71 bit to fit in a full sized drill chuck is a pain.
  • Small drill bit. Or several of them, since they're so easy to break. If you're drilling soft materials don't spend a lot of money on them. This is the cheapo set I used.*
  • Right angle jig. If you don't have one I'll explain how to make a quickie out of old scrap wood (like this one) in step 2.
  • Business cards or notecards. Anything is fine as long as they're uniform thickness. This is what we will use to determine the space between the holes.
  • Rubber bands I use a number of them to hold stuff in place. If you have some small clamps or vice grips or whatnot, those would be useful as well.
  • Safety glasses (not pictured because they were on my face when I took the photo).
  • Practice Material. Scrap wood or plastic or whatever so you can practice before going at your final project. Trust me, you won't want to drill your final project the first time out. You'll probably also want something disposable to put under your material as you drill through it.

It's also helpful to have a dust brush, dustbuster, and/or vacuum cleaner around. While you're working keeping the workspace clean is vitally important because any small bit of sawdust or debris can throw off the accuracy.

* Often drill bits smaller than 1/16" are called "wire gauge" bits. This term can be helpful when shopping for them online.

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Graham Lane11 months ago

Very good idea! I might use a round head woodscrew instead of card on one side. Measure the pitch of the thread and screw or unscrew one complete turn if the distance you require is one pitch. Fraction it if you want anything different.

Put two screws in one face and one in the other. This keeps the three-point location rule.

The gap the screw-heads create will also take care of any swarf or shavings that slip down the sides.

Card is probably simpler though!

Well done 'ible. I appreciate the sketchup drawings to fill in forgotten photos.

dombeef4 years ago
For the last picture you could use a presured air can to get the burs out
yoshhash5 years ago
I tried doing something similar to drill holes into wood. Some types of wood are very problematic because of the variable density/resistance of different parts of the woodgrain- the bit will wander. Even if you clamp the workpiece down with something sturdier than rubber bands, the drillbit will bend, especially if there is another hole closeby, it tends to gravitate towards it. Anybody have a solution to this problem?
You have to mark the hole to be drilled with a punch therefore making a small dimple. This will prevent the drill bit from wandering.
Grathio (author)  LeumasYrrep5 years ago
Yup, punching the hole will keep it on target, though I'm not 100% how to do it accurately at this scale. The first thing I'd try is putting a punch in the chuck and use the same method with the card spacers to mark the holes first (just pull the drill down with the power off to dimple the surface). Then after all the holes are marked put the bit in and drill the holes.

For a punch I'd try a needle, or possibly an even smaller drill bit, but upside down so the blunt of the shaft is doing the punching.

The second thing I'd try is drilling a hole through a piece of steel then place it on the drill surface and drill your holes through it. It might keep the bit from drifting to the side. *

But whatever you do I don't think you'll be able to get holes as accurately in wood as in other materials for the reasons you state. Wood grain can be surprisingly inconsistent.

* I haven't tried either of these things, it's my best guess. If you find something that works, please post it.
nflloyd Grathio4 years ago
For toy fabrication I have used 1/4" - 1/2" aluminum bar to make a guide hole jig. Multiple diameter holes in a single piece of aluminum gives you a very versitle tool. If you make a set of center pins matching the holes (turned steel dowel pins or rod stock with sharp points) you can accurately locate the jig to the work. You put the locator pin through the jig, put the sharp point on the work and then slide the jig down to the part to clamp. You remove the guide pin and then drill!. You get amazing results with this method for small diameter holes. In order not to clog the jig you will need to clear the hole frequently as you drill. This method works virtually as a freehand drill press.
With very small bits the flex of the bit itself is a problem. So I use a gued piece which I have previously drilled and clamp it on top of the wood. that seems to keep the bit from drifting.
That's a tough on. Could try choking up on the bit only letting maybe 1/3 or 1/4 or the bit to hang below the face of the chuck. This should help get the hole started. I doubt they have any this small but there are bits called "Center Drills" They are short with a HEAVY shank and are used to mark or start holes in situations like this, but I'm not sure how small they make them.
Grathio (author)  billz2605 years ago
I had the same thought when I was trying this out. But I found that the drill bits--at least the dime store ones I'm using-- the grooved# part of the bit was just the slightest bit thicker than the shaft. So when I put the bit really deep into the chuck it spun off center.

Might work with better bits though, so it's worth a try. If it works for you, post a followup!

#A patch to whoever can teach me the proper name of the grooved auger-like channel part of a drill bit.
The drill has 2 flutes to allow the waste material to escape. The section in the middle is the web. The 2 cutting faces are the lips
it's called a flight
Grathio (author)  mkeith545 years ago
Bingo! Thanks!
you can get pretty fine but they are still about the mm isze for the common ones . any good engineering stockist should be able to supply smaller but sit down before they tell you the price!!
I had the same problem with wood. The best solution I found is to use a punch or even a nail to make a small indent where you want the hole. It allows the drill bit to get started in the right spot without wandering around
This is absolutely the way to go - with wood and metal. Use a center punch (or centre punch, if you're Canadian). In making small holes in metal, the classic metal-drilling protocol should be observed. Oil it (the piece being drilled) with a light mineral or petroleum-based oil. As soon as the bit hits the metal, it feels more "comfortable," and is less inclined to wander. Verrry slow is always best. Also, let up the pressure every five seconds or so. The oil also prevents the build-up of heat (saving the drill bit), and provides the cleanest bore possible. (It's amazing the stuff that I learned from my late Dad.)
In wood, a bit made especially for the purpose cuts a cleaner hole than an all purpose bit.
The key to keeping the bit from wandering due to variable resistance is to greatly slow the speed the bit descends. The finer the bit, or the closer to another hole, the slower you will need to go. It requires extreme patience.
chipf yoshhash5 years ago
a good way to make sure the bit does not wander is drill the hole first with a finish nail close to the diameter you need for small holes, just cut the head off and chuck it up. for larger holes i use forestner bits or bradpoint bits they dont wander do to having a pilot point.
boondocker5 years ago
As far as shims go, a metal feeler gauge set would be flexible, noncompressive, and small enough to fit in confined spaces, as well as having your distance measurements etched in the face of each shim. Two sets would set up your X and Y axes, I would think.
Battman5 years ago
Great idea! Worthy of the Galactic Institutes' prize for extreme cleverness.
Grathio (author) 5 years ago
I want to take a moment to say thanks to everyone for the positive feedback and suggestions. It really makes the time I spent slaving over a hot camera feel well spent. Once things settle down I'll try to incorporate the best of everyone's suggestions (With credit of course). If you use this technique, send me a photo or post it to comments and I'll send you a Special Achievement patch.
heathbar645 years ago
If your using multible layers of paper/ cardstock for shims, they can compress quite a bit. affecting your acuracy. You need to make sure you have the same clamping pressure each time you set it up to maintain the same spacing.
Grathio (author)  heathbar645 years ago
If you're worried about compression you can use metal sheets rather than paper cards. The sheets they sell at the hobby or art store (like this stuff) are generally machined with very tight tolerances and won't deform under clamping.

You'd probably need to cut them into smaller pieces and be sure you don't have any rough edges to mess up the spacing. There might be something else at the hardware store that would be a better size that wouldn't need trimming. Anyone have any ideas?
Yendeg5 years ago
as for deburring i would us the larger drill size or use a very sharp x-acto knife
Grathio (author)  Yendeg5 years ago
Th problem with the good old "larger drill bit" trick is that you don't touch all the holes exactly the same way it ruins the symmetry--some holes look bigger than others. And X-Acto is even worse at those scales. (At least with my shaky hands. You may have better luck.) I got an email from a helpful guy named Manny who found a good solution. Essentially it's flossing the holes with a thin wire or nylon line. I just tried it and it works pretty well, removing the burrs without enlarging or otherwise disrupting the hole.
jdmorse5 years ago
In my machine shop we have a small drill adapter for the drill press that allows you to use very light pressure when drilling and will chuck up to any larger drill press. This one is from MSC
Very cool, but I've always used a piece of breadboard as a drilling guide
PKTraceur5 years ago
I did something like this on a very thin sheet steel, with a carbide tip about 1/32 diameter. I chipped the bit after my 30th hole, and the bit hit my cheek. Ow... *Note: Remember saftey goggles next time. B-e-a-utifully pictured instuctable. -PKT
Geosync5 years ago
Oh, man! Great Instructable. Innovative technique and very clearly described. Thank you.
hammer98765 years ago
Very nice. The photos explain almost the whole thing. I kept thinking clamps would be sturdier than a lot of rubber bands, but obviously you still managed to create precise, tiny holes. Awesome!
Grathio (author)  hammer98765 years ago
Yeah, clamps would be better, but I didn't have any that would fit in there and not get int the way of the press. If you do use clamps it's best to not clamp too tightly so you don't squish something out of alignment. Thin rubber bands were plenty for this project, it just needs to be held in place against whatever torque a wire thin drill bit can generate.
thepelton5 years ago
I have a special table that I can attach to my tablesaw with two Incra-Jigs(tm) on it at ninety degrees to eachother. They allow precisely positioning of holes as close as 1/32" (.79mm) from eachother, center to center. You can buy them at
tundrawolf5 years ago
VERY cool. Thanks!
For deburring, use either the drill bit you drilled the hole with, or a slightly larger bit, and just pass it through the hole, twisting it a little. If you're using a larger bit you can just press its tip against the hole and turn it to slightly chamfer the edge of the hole and take off most of the little bits of stuff left by drilling.
Stunning. Thank you.
desertdog5 years ago
Very good idea. I will use that.
Makers5 years ago
Enjoyed your description of the process. Don't need precision holes right now but maybe in the future. BTW speaking of drill bits, any advise on choosing good bits (average size) types? Some I have used seem so much better than others but I don't know what exact type they were or where I got them.
A nether way to de burr doles is to use a slightly bigger drill bit. You can do this by hand or with the drill press.
JimmyM5 years ago
You can also use resharpened carbide drill bits. I found a big set on eBay for ~$25. Thay have 1/8" shanks and the resharpened ones work just fine. Plus they last many many times longer than steel wire gauge bits when drilling FR4 and you don't need a Dremmel chuck, the 1/8" shanks fit the standard collet. The only drawbak is that they break really easily if you side-load them. The drill press prevents this.
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