DIY Fine Countersink

Make a countersink (deburr) hand tool with fine pitch – ideal for finishing touches on your 3D prints.

This tool is basically a handle for an off shelf rotary boring cutter. They can be found with fine pitch and very sharp edges. Typical hand countersinks are design for wooden usage and they are not ideal for delicate 3D printed components.

Boring cutters could be very sharp so a cap is included :)

Print instructions

BOM

• 1 × Rotary boring cutter K1206M06 (⁕)
• 2 × M2.5 x 8mm Screw
• 2 × M2.5 Nut
• 1 × Self-tapping screw 2.9 x 19 mm (ISO7049 or similar) - optional

⁕) Design is based on 90° conical cutter with ∅ 6 mm shaft and ∅ 12 mm head. It could be found on aliexpress (e.g. link). You can select different one. Only limitations are dimensions of shaft and head (if you want to use cap).

Assembly instruction

There is gcode for Prusa Mini, however I suggest to slice it yourself based on your needs. No support necessary. Consider using brim for the cap.

There is one layer of filament covering holes on the holder and the back parts (this eliminates necessity of support). Use small drill bits and clean them before assembly.

There are two options:

A) Free rotary back part

• Put pin part between handle and back part.
• Tighten them together with self-tapping screw just enough that allows free rotation

B) Fixed back part

• Pin part is not necessary. There are holes for better alignment (use 10mm cutoff of filament as alignment pins)
• Parts could be screwed tightly or glue together.

How to fix cutter with M2.5 screws and how to use cap should be self-explanatory.