29 January 2010
Author: Giorgos LazaridisHomemade Foot Pedal For PCB Drills
This is the easiest project that i have upload to this site so far. I made this in a hurry out of some old materials that i found in my junk-yard. This is very handy though. I make my own PCBs and i do a lot of drill-job. A medium size PCB may have more than 100 holes! Although i have a dremel and a horizontal drill base, i find it easier and much much faster to drill the holes with an old 12 V pen-style mini drill that i have since i was 16.
So, back from the dead, this drill will regain the place that it deserves... and that place is over the workbench. This drill had a rocker switch on top of it. To center the drill in a hole quickly, i used to turn off the drill, place the bit in the center of the hole, and then turn it on back again. With the turn-on and off, i had always success in centering the hole without damaging the copper nearby by accidentally touching the rotating drill on a wrong point. But this turn on and off procedure was done with my thumb, and it was rather uncomfortable. After some 50-60 holes, my thumb was already hurting.
With no further ado, i present you the worklog. First of all, i had two pieces of thick (10mm) white acrylic glass cut into half, about 21mm each. The one is the base and the other is the pedal. I found two old (and a little bit rusted) hinges. Using a small piece of wood, i had them aligned in position, about 30mm away from the edge. This distance is selected on purpose for anatomical reasons. Then, i marked the holes of the hinges, drilled and made threads for M3 screws. I fixed the hinges with the screws and washers:
The hinges are now fixed on the base. I had to fix the pedal on the hinges as well. I placed the pedal perpendicular to the base and attached to the hinges. Then, i marked the holes of the hinges on the pedal piece. I drilled another 4 holes and made again threads for M3 screws. Here is a tricky part. I had to use screws with thin head, countersink screws actually. This is because when the hinges are closed, the screw heads on top will touch the screw head on the bottom and will cause problems.
The pedal needs of-course a switch to operate. I had an old (i do not know from where) push-button with a rather strong spring, perfect for the job. The base for the switch is made of 4 acrylic glass pieces. One has the hole (12mm) that the switch-top will be screwed to. This piece is made of 4mm acrylic glass, drilled with my favorite cone drills. The second piece is made of 10mm acrylic transparent glass. using a 15mm drill and a jig-saw, i made place inside this piece for the switch to fit in. Then two identical pieces goes at the bottom of the switch base as spacers. All these pieces are glued together using the special acrylic glass glue. The base now is a fixed piece. The switch is put in the base from bellow, and fixed with it's screw from above.
Now i had to attach this piece to the base of the pedal. I used long alen-screws M4mm to fix it. I drilled 5mm diameter to the switch piece. Then, i placed this piece on the pedal base and marked the holes. I drilled and made threads on the base. The can now be fixed tightly. First, i had to deal with the electric connections. I used an old power supply that i found again from the same junk-yard that i found the other pieces. I cut the positive wire and passed it through the switch. When i soldered all the wires, i fixed the switch to the base of the pedal.
The Pedal Is Ready
As i told in the beginning, this is the easiest project i have posted so far. The pedal switch is ready to be used. The construction looks very solid. The material that i used may come from my junk-yard, but this pedal will last a lifetime. As i hear some strange sounds from the bearings of my beloved drill, i am sure that my new drill will inherit this pedal. Or maybe, i will make a proportional pedal, if i find a reason for this... Here is an overall photo from this project: