Semi-automatic PCB Drill Press

Kiss the days of breaking bits while drilling through-hole PCBs goodbye thanks to this semi-automatic drill press (translated). Now it’s not going to line up the bit with the exact location of the hole (that would make it a fully automatic drill press). This works by lining up the board manually, then stepping on a pedal to activate the plunging motion of the drill.

A linear motor is responsible for the smooth, accurate motion along the Z-axis. Many hobby setups use a Dremel drill press, or even rely on prayer-based systems such as doing it free-hand with a rotary tool or by using a piece of acrylic as a guide hole. The hobby drill press tends to have some play in it and free-handing with tiny bits that are as fragile as glass both result in far too many broken drill bits. In the video after the break you can see that the linear motion is perfectly plumb with the table of the device, preventing the movements that cause breakage. The addition of the pedal makes it easy to position the boards because you can use both hands.

Having a tool like this takes all of the frustration out of using through-hole parts.


26 thoughts on “Semi-automatic PCB Drill Press

  1. Based on the translated page, this appears to be a commercially-produced PCB drill machine which had occupied the university’s lab “since time immemorial”. Not a criticism, just a note. The linear motor is a surprising and spectacular enhancement. Congratulations to this guy for a fast and precise labor-saving device.

  2. The quick-hack hinge-becomes-pedal is amusing, I once made a pedal that was very similar.

    I think it’s nice how quick it goes.
    What annoys me with drilling though is lining the drill up just right, that tends to not always go right, so maybe adding an aiming system, either laser or a small camera above it might be an idea.
    (I myself find staring at a laserdot/line not a good experience that’s why I added camera. but maybe there are other ways you guys can think up.)

  3. I use a Dremel drill press. It did have too much play in it too, mainly side-to-side play. A quick fix that has worked was to drill a horizontal hole in the top of the heavy rod that slides up and down. Then, put a 4 inch bolt in the hole and a rubberband from the outer end of the bolt to the back post. This puts a constant torque on that rod and prevent any side-to-side play without interfering with the normal up-and-down operation. Works wonderfully.

  4. @Hackerspacer

    Think hard about the drawbacks of each of those methods, and carbide drills start looking pretty good. Some board houses can do laser vias, but drilling is the standard for precisely dimensioned holes.

  5. [many many moons ago] After giving up on the prayer method I purchased a cheap as possible “hobby” drill press. And yes, it does have slop in it. The key to never breaking a bit again was to also etch the centre of the pad to about 1/10th of the hole size so that the loosely held board self centres on the bit when gentle pressure is applied. The drill press allows the firm even pressure required to drill the hole. The hole is perfectly centred and not somewhere mainly inside the pad. Now I only ever change the bit when it’s blunt. In my experience the only way to do it faster or better is fully automatically.

  6. Why would non abrasive waterjet not be a viable method for cutting holes in fiberglass boards? Delamination concerns? Fraying?

    Just because something is standard does not mean it is the absolute best way.

    Granted, drilling holes works very well but it just seems like an awfully time consuming task for commercial level production.

  7. @Hackerspacer my first guess is accuracy. Have you seen what the starting hole/place looks like on a commercial waterjet?
    Things usually become standards because… many people thought about it longer and harder than you have and tried many different ways. There are plenty of youtube vids showing how fast it can be done with the appropriate equipment. On the interwebs google is your friend ;)

  8. I own a waterjet, so yes.

    Pierce holes on my waterjet go down to 0.002″ and as large as 0.028″. Positional accuracy is roughly 0.003″ – precision ballscrews, feedback encoder based servos and linear ways.

    It cuts awfully cleanly. Non abrasive cutting is amazingly clean given slow cutting speeds but the pierce holes are not as clean, depending on the material. Plastics tend to leave a pierce mark, for example.

  9. I focus my design as much as possible to a 0.1 inch grid. I then use a jig made up of two pieces of 0.1 inch perfboard with occasional pins. one is connected to the table, and the other, with the board to be drilled is free. By moving the free part of the jig until it clicks into place and then pressing the pedal to bring the dril down I can very quickly drill out a prototype board. My pedal was part of scrap drum-kit and i attached it to the hobby press using a bicycle brake cable.

    Another trick i regularly use is a cigar box below the pcb being drilled with a red pointer laser shining up through a 0.8mm hole. As you line up the pad you see a flas of red in the hole in the middle of the pad. Maximum red = pedal time.

  10. “Non abrasive cutting is amazingly clean given slow cutting speeds but the pierce holes are not as clean, *depending on the material*.”

    Key words here are *depending on the material*. Aluminum is clean as can be with abrasive piercing – a little hazing around the pierce point due to longer dwells compared to cutting speeds but no burrs or deformations.

    Thicker (0.5″ and up) polypropylene tends to bunch up with abrasive and isn’t as clean. Smaller, thinner material with water only cutting isn’t the same. The pressure also plays a role, as well as if the abrasive is on when you start cutting or if it starts water only and then you add abrasive.

    Material thickness, if it is a composite or not, how brittle it is, etc all play a role. So there is no single, simple answer.

    Taking my quote out of context and then using it in an attempt to prove your point is childish and unproductive. The answer I originally posed was are other processes a suitable (or better?) alternative to putting holes in PCB material. There may be, there may not be. I generally always believe that existing processes, while good, may not always be the best method of doing things. Just look at titanium refining. The Kroll process was used for a long time. But not the FFC is showing that it may be a better way of refining titanium.

    Every now and again you see things like this as well:

    Water only waterjet *may* be a method to do so although its use may be somewhat outside of the scope of the hobby hacker community due to access to such a machine being far less common than a drill press (although I suspect that many of the readers of this site are not just hobby hackers).

    I guess I will have to toss a water only nozzle on and throw some scrap material on the table and give it a go and see what happens.

  11. @Hackerspacer
    “When all you have is a hammer….”
    You have everything at hand to try your idea, yet you spend more time typing than it would take to test? And I’m the childish one? Have you tried it yet? How about now? …now?

  12. @hackerspace

    Why no water cut pcbs?

    Cost. Drill bits are cheap and last a long time. You only need point to point control. Water jets consume considerable power compared to a pcb drill/router. Water jets are noisy and require considerably more maintenance.

  13. I don’t doubt that drills work very well. They are the industry standard for a reason. Cheap, effective although they have a habit of breaking. Is there a better method – whatever form it may take – is my only hypothesis here.

  14. A standard water only waterjet needs fairly little maintenance, by the way. HP seals are the most common item and those are every few hundred hours. Non diamond orifices last ~ 40 hours but are easy and simple to replace – sort of like drill bits.

    Other items like LP seals, cylinders, check valves, blow down valves, etc last 500 – 2000+ hours or more each – especially if you have high quality water or good DI control / particle filtration / soft water.

    So – yes – more time to “keep running” than a drill. But not as bad as you might think. Not too loud either (on par with a drill) and costs are about $15 – $20 an hour, if your time is considered free and you aren’t using abrasive (where the bulk of the costs come in).

  15. @Hackerspacer

    So what’s the deal, you’ve spent your whole day on this thread. You’ve got our attention…

    Test your hypothesis, and post your results.

    MUST HAVE VIDEO, lots of good video, or I’m not interested !!

    Step-up or… don’t??

  16. Here is idea for someone building drill: Put drill and mechanics under table. When you press leg pedal drill bit comes up from table. Add laser cross hair to point position where drill bit is going to pop up.
    Friend of mine told that commercial version of this exist, but I have not seen one.

  17. @Hackerspace: Quit being a gobshite. If you have a better way we are all ears. If not move along.

    To the guy who made the drill press, that is bad ass, very well done. We need more hacks like this one on the site!

  18. @Tommi Rouvali thats a good idea :-)

    Can anyone suggest a way to make a cheap linear actuator from spare parts? I’m thinking something like a vertical stack of neodymium magnets held in a rigid frame with a single field coil around it.
    Use rails and other parts from an old inkjet printer to make the linear bearings.

  19. @bothersaidpooh
    Why make it that hard? google “woodrat plungebar” to see how to do your linear actuation via a simple lever. Also bim the drill point will only need to travel less than 5mm.

  20. Drill bits break for two main reasons: shaft buckling and chip jamming.

    If you press down too hard on a drill bit, the force can cause the shaft to bow outward. That isn’t enough to break the bit on its own, but the fracture mechanics of bending while spinning are amazing. As a point on the surface of the shaft moves to the inside of the bend, it’s put under compression. When it moves around to the outside of the bend, it’s put under tension. That push-pull cycle repeats every revolution.. several hundred or thousand times per minute for most drills.. and every cycle rips even microscopic cracks open wider. That weakens the metal, allowing it to bow even farther, putting even more compression and tension on the weak spot.

    I’ve seen demonstrations of a 1″ steel bar mounted in a lathe snapping under only a few pounds of side pressure. It takes hours to happen, but it does happen. For a small drill bit, the interval between bowing and snapping is probably less than a second.

    Chip jamming occurs when the particles making their way up the flutes pack together. The packed chips act as a wedge between the bit and the wall of the hole, locking that part of the bit in place. When that happens, whatever part of the system is weakest will give. For large, strong bits, you’re most likely to rip the workpiece out of its fixture, or maybe stall the drill motor. For small bits, there isn’t enough metal to stop the drill motor or spin the workpiece, so the bit is the part that fails.

    The solution can be reduced to one word: pecking.

    Instead of trying to drill holes in one pass — which implies continuous application of pressure and a long path for chip evacuation — You make several short passes, each going no deeper than half the drill’s diameter. For a .010″ hole, that would mean a series of pecks .005″ deep. Pecking minimizes the force that might produce bowing, the time that a bowed bit might spend spinning, and the amount of chip that can accumulate in the flutes of the drill.

    .005″ per pass might not sound like much, but with a little practice you can make a couple of pecks per second. Drilling through 1/16″ PCB only requires a dozen pecks or so, for a total cutting time of 6-10 seconds per hole. For hand drilling, you’ll probably spend longer lining up on the hole than pecking it through the board.

  21. Another point, re: laser guides for drilling.

    IMO, don’t bother unless you have a beam that’s less than 10% of the hole diameter. If your bit is .020″ and your laser beam is .050″ across, the beams won’t tell you anything useful.

    For hand drilling, the best thing you can do is pre-punch dimples in the center of each hole.

    For copper and plastic, a heavy sewing machine needle makes a good punch. Line up the point on the center of the hole and tap the blunt end with a light mallet.. and I do mean ‘light’. The shank of a 3/8″ drill bit will give you more than enough force.

    As long as the dimple is big enough to catch the tip of your drill bit, it’s big enough. The dimple will guide the bit to the right location and keep it from wandering as it begins to cut the material.

    Pre-punching does add an extra step, but it’s much easier to place a dimple precisely than it is to drill into a smooth surface precisely. And once you do move the workpiece to the drill, the dimples make lining up holes trivial.

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