precision drilling – Mike of Chronova Engineering built a milling-machine attachment that moves a drill bit up and down with extreme precision for work that normally breaks 1 mm bits—and can feel nearly impossible with 0.1 mm tools. After early setbacks tied to a damaged collet lo
Anyone who has tried drilling with something as small as a 1 mm bit knows the drill press is rarely the weak link for the job—until bits start breaking.. With a 0.1 mm drill bit. the challenge shifts from “difficult” to “near-impossible. ” and that’s the gap [Mike] of Chronova Engineering set out to narrow.
The solution is an attachment for a milling machine designed. at its core. to move a rotating drill bit up and down.. That sounds simple until you remember how unforgiving micrometer-level runout can be.. Even a good-quality chuck typically has a runout of 30 to 50 microns—already approaching half the diameter of a 0.1 mm drill bit.
In the mechanism’s layout. a collet is mounted in the milling machine’s spindle to transfer rotation to a second spindle.. That second spindle is paired with a runout-compensating drill chuck. and the motion is controlled through a lever and counterweight that let the user make small. low-force movements.. A dial indicator provides a direct readout of how far the bit’s descended. turning a “feel” job into something you can measure.
The build itself leans into precision and practicality: most parts were machined out of steel or brass. while the handle was made of titanium to reduce weight.. But when the finished device was mounted to the milling machine. the measured runout was severe—enough to derail confidence in the mechanism right away.
After “much investigation and reworking,” the issue wasn’t the drill-press-style motion system after all.. The problem turned out to be a damaged collet locating pin, not a fault with the drilling mechanism.. With that fixed, [Mike] ran a first test: drilling a 0.1 mm hole 1.8 mm deep.. He then escalated the challenge by drilling six 0.1 mm holes in the end of a thin steel wire.
The outcomes weren’t perfectly uniform. but the imperfections were subtle enough that it took a scanning electron microscope to see them at all.. That level of restraint is also part of the trade-off: the mechanism “won’t help much” with very fine drill bits. the way an ordinary tool won’t magically prevent breakage.. Still. if the goal is a precisely placed hole. the project suggests the path forward is controlling where the bit ends up. not just how fast it spins.
There are also a couple of practical realities attached to this kind of work. If the bit does break in the workpiece, the source notes you might be able to dissolve it with alum. And for when drilling needs to be guided more directly, it points readers to a “periscopic drilling camera.”
What emerges from the testing is a tight cause-and-effect chain: the measured runout looked severe once the attachment was mounted. the team investigated and reworked. the culprit was identified as a damaged collet locating pin. and only then did drilling tests proceed—starting with a 0.1 mm hole 1.8 mm deep and expanding to six 0.1 mm holes in thin steel wire.
For a look at the device in action, the build is shared in a video: https://www.youtube.com/watch?v=KrStsdNG5go
precision drilling drill press 0.1 mm milling machine attachment runout collet scanning electron microscope alum