2020/2040 V-Slot OpenBuilds Counterbore Hole Jig

The primary function of this jig is to help align and create counterbore holes in OpenBuilds V-Slot rails to create blind joints.  The counterbore holes are created using a two-stage drill bit, which creates a 5mm hole and a 9.0mm counter bore.  The jig can be used for 2020 or 2040 V-Slot rails and allows for several positional alignments. The hole placements when aligned to the edge of the V-Slot railing will have a 10.0mm offset from the edge with the holes spaced 20.0mm apart. 

I found the drill bit by searching Amazon.com for the following:

Cobalt Two Stage Step Drill Bit M5(5.5-9.0) See image for reference.

Usage:

1. Start by mounting the jig at the end of the extrusion so the drill bit can be adjusted for depth.
2. Adjust the bit to cut even with the center hub of the extrusion.
3. Mark the depth of the bit with a marker or tape.  (See Image)
4. Mount the jig at the location where you want to drill.  I recommend using two mount points to have a firm connection to the rail.
5. Place the drill bit in the chuck of your drill, and adjust it so the mark created in step 3 is even with the chuck.
6. Drill the holes. 
7. Adjust the drill depth as needed.

Overall Impression:

I felt the jig works for my needs, however when drilling the bit tends to catch.  In addition, the bit has a slight tapper which I personally don't like, but it does not detract from the intended purpose.  This model is not intended to be used for designs which you would like to add rollers to, as it will cause them to skip since the counterbore cuts into the v-slot.  This issue can be seen in the provided images.

Printer Settings:

Layer Height : 0.4

Infill : 50%

Material : PLA

Supports : Yes