Drilling Into Half Inch Diameter Tubes

It didn't take long before my new old drill press was put to work doing something that was difficult without the tool: I needed to drill a total of eight holes through three half inch diameter aluminum tubes, perpendicular to the tube's axis.

Because the surface is curved at the point where drilling starts, it takes a skilled hand to perform the task via freehand held drill and workpiece. I did not have such skills in my hands. Putting the workpiece in a vise helps, but still difficult for me to keep a hand held drill on center. What I needed was a way to hold both the workpiece and the drill bit in rigid relation to each other, meaning a custom workholding solution bolted to the drill press table.

It was built using a very cheap Harbor Freight vise. Its jaws were removable and I designed and 3D printed replacement jaws with a V profile to better hold a round object. The other benefit of 3D printed plastic jaws compared to metal jaws is the reduced chance of marring workpiece surface.

The next step is to bolt this vise onto the drill press table. I saw mounting slots on both the table and the vise, and their slots were in the same pattern. I naively thought this was a standard form factor and they will easily line up.

When I put my vise on the table, I found that they did not.

Fortunately even though they did not actually line up, they left enough room for me to use a smaller bolt to try to make things work. In this case, my stockpile of 1/4"-20 bolts.

The slots are too wide for the typical 1/4"-20 washers I had on hand for this bolt, but again I could turn to my 3D printer for custom solutions that help me bolt the vise to the drill press at the location I needed.

It took some adjustment to bolt the vise exactly where it needs to be. (Tip: double check to make sure the drill press table isn't itself moving!) But once everything was tightened down, the jig made drilling the holes I needed very simple.

Public Onshape CAD file for this project are available here.