Drill Press File Jig for Pointing and Chamfering

This jig makes it easier to create a point or chamfer on the end of round stock using a drill press. It holds a file or a piece of wood with sandpaper on it at a specific angle so it can be presented to the spinning workpiece.

Fits files up to 0.8" (20mm) wide and 0.16" (4mm) thick, which fits the random 8" mill files I have sitting around.

The angles on the STL filenames are based on the included angle they produce on the end of the work. In other words:

• The 60 degree models produce a 60 degree point (that is, the file is held at 30 degrees to vertical.)
• The 90 degree models produce a 90 degree point (that is, the file is held at 45 degrees to vertical.) You could also describe this as creating a 45 degree chamfer.

Additionally, there are versions for an M6 screw and a version for a ¼"-20 screw. I recommend using brass, nylon, or printed screws to avoid bearing a steel screw tip hard against the teeth of your files, which could possibly dull them somewhat -- the noise a steel screw makes while tightening down on file teeth is… concerning.

Printing instructions:

• Print two of the same model to hold each end of the file.
• PLA, PETG, or other decently rigid filaments should work fine
• 0.2mm - 0.3mm layer height
• Print on its side (this is how the STL is naturally oriented.)
• Should not need infill or perimeter count above what you use for general purpose prints.

How to use:

You need two prints, one to to support each end of the file.

Put your file in the jig as pictured. Your file handle may have to be removed to avoid interfering with the table. For safety it is probably best to still cover the point of the file tang with something like a smaller block of wood.

If you are converting the entire end of the work to a point, it may be good to rough it out using a file by hand or belt sander first so you do not have to do all the work on the drill press. The easiest way I have found for roughing a point on a small metal rod is to chuck the workpiece in a cordless drill and spin it while pressing it against a belt sander. Run your drill in forward or reverse as appropriate so the rotation of the work and the direction of the belt oppose each other.  This can get you very close, this jig lets you further flatten the cone and true the angle.

Now, chuck the work in the drill press and tighten it. Set the height of the table so that the work contacts the file at the right height, but also that you will not run the file into your chuck jaws. Make sure there is enough clearance between the file and your chuck and its jaws.

Run your drill press at a low RPM setting. File away from you, on the right hand side of the part, with your file tang towards you. (Drill press spindles turn clockwise looking down at the table; this arrangement means the work is spinning towards the cutting side of the file teeth, and you are pushing in the direction the the file cuts.) 

Use gentle pressure and slow filing strokes. Radial stress on the drill press spindle is not good for the bearings, although I do not think doing this from time to time carefully will noticeably shorten the life your drill press. Additionally, going slow and gentle reduces the chance of getting things out of concentric and introducing wobble, which is harder to recover from.

Please note, filing or sanding parts in the drill press (or against a belt sander for that matter) has the potential to make them HOT. Be careful when handling them immediately after working on them. Do not overheat your file, either.

In my case, I used a file in the jig to establish the correct angle. Then, I used a paint stir stick (cut to fit into the jig) with 400 and 1000 grit sandpaper applied to refine it. I finished by making a few 60 degree holes in basswood and putting metal polish in them, and just briefly running the workpiece tip in the holes.

Disclaimer: Power tool safety is your own responsibility. Read and understand all safety instructions for your tool. Wear your PPE, which for a drill press is at least safety glasses and hearing protection. Do not do anything that feels unsafe.