Variable Speed Micro Drill

In my various hobbies and projects, I occasionally need to drill VERY tiny holes. Think wire-size bits and pin vise. Beyond tedious. So I decided I needed a micro drill.



For starters, I bought this Chinesium 12VDC motor and chuck. Chuck is good down to .3 mm! I figure for $11, what the heck, right? To my surprise, it works quite well, but it turns at about a bazillion RPM.



So, as the next step, I bought this (also Chinesium) variable speed DC motor controller. It uses Pulse Width Modulation (versus straight voltage control) so it provides reasonably constant torque.



The whole thing is powered by a 200 watt computer power supply I had laying around. I bent up a bracket to mount the controller to the power supply. It sits right above the fan on the PS and has a hole under it to provide a little extra cooling. Probably overkill no more than it'll be used, but figured it wouldn't hurt. Also added a switch to turn the PS on and off. The controller will turn the motor off with the pot all the way CCW, but again...belt and suspenders. I re-pinned the standard computer connectors as a way to plug the drill into the controller and be able to unplug it and store it separately. May also find other uses for the power supply and controller down the road.

Less than $20 and a couple of hours of my time which doesn't count cuz I had a ball doing it.

thats the kind of ingenuity and resourcefulness that I like . much more satisfaction in creating a solution rather than just throwing money at it.

peanut said:

thats the kind of ingenuity and resourcefulness that I like . much more satisfaction in creating a solution rather than just throwing money at it.

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Side effect of growing up on a farm with no money trees plus a life-long fascination with re-purposing stuff to do things it was never intended to do. Sometimes it even works!

I use the same (or very similar) PWM driver to diag externally variable displacement A/C compressors on vehicles.

Downeaster said:

Side effect of growing up on a farm with no money trees plus a life-long fascination with re-purposing stuff to do things it was never intended to do. Sometimes it even works!

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My one grandfather was a Polish immigrant farmer, and was a young man during the Depression. He was also an Army engineer during WWII in New Guinnea, and a general contractor after. We lived about 1/4 mile away from each other, so me and my sister spent summer days with them. I learned A LOT from that man!