I've searched a column drill as the "Proxxon Bench Drill Press TBM 115" but it's a little too expensive. I've found also a vertical stand for Dremel alt 50€, but it was a model with a single metal column as rail, similar to the most you can see with a "drill stand" search, and it had a low precision in horizontal movement of the bit. In fact you felt the head moving of about a millimeter, which is a lot when your bit is so narrow. So I decided to build it by myself.
The slide is a "macro rail" for photography which you can find on eBay at about 10$, but I already had a couple of them. The other parts you need, other than the drill, are only:
- a strong spring (but also a big elastic is good)
- some wood boards
- some screws
- a nail
- 5 inch of a little aluminium cilindrical bar (as the ones of the TV antennas)
- a wood base
- and two inches of aluminium pipe (this also isn't so essential)
Behind the rail you find the hole for 1/4" screw, I've inserted a gum disc to make the rail fixed on the column, and avoid mutual rotation.
It could be useful know that in the two more very little holes are two hex screws which loosen or harden the rail flow. You would set them to increase the precision and to slow down the drill when you release the lever.
The little nail you see it's to stop the drill at the resting position, so that the spring remains with the right tension.
In the hole of the little knob I've screwed the blocking hex screw. To avoid it unscrews you can add a drop of glue before screwing it. You can remove it to loosen the spring and disassemble everything.
You could extract or insert more the bar so that you can choose the right high of the drill over the base. Unscrewing the side hex screw you can let the toothbrush making some turns. Each turn raise or lower the rail of about 1 centimeter, this is the step at which you can set the high of the drill in the resting position.
If you want to use various dimensions bits, I suggest to add an addictional thick wood plate under the bit, and glued it on the base with a double-side scotch tape, so you can change it when the hole becomes too large.
Of course if you want to make everything prettier you could paint with black the wood parts.
You will see that the precision and stability of this tool is impressive. The only improvement I could think is to give more distance between wood column and drill, so that you can work on bigger objects.
[UPDATE: I've built a block to add distance between column and drill, so you have more space for pcb, and I also made a more nice base. I explain you the updates in next few steps]
I've drilled six holes to link sturdily the column. On the bottom surface of the board I've drilled with a cone bit the grooves to keep inside the screw heads.
The holes are not centered on the short side of the board because pulling the toothbrush (or the lever, as you wish) you make a vertical force which has to be opposed by a larger base.