Contour Rotary Bit

Configurable rotary bit that features adjustable teeth for easily removing material in a specific way.  Can be used for repairing multi-layer FRP, cutting out sockets for drains or flush thru-hull fittings, flattening uneven surfaces, etc.

The small bits (teeth) can be any round grinding/cutting burs: diamond/stone (composite, glass, ceramic), carbide (metal), etc.  Thinner bits will make it possible to replicate contours of higher resolution.

Parametric, open-source, free.  Designed using ShapeScript.

Parts

• ? x drill bits (must be equal in length);

• 1 x bolt;

• 1 x washer;

• 1 x nut;

Printing

Use strong and rigid filament (e.g. PETG) — something that won't melt or break easily.  Keep it light yet strong — not more than 30% infill.  The bushing can be made out of anything rigid, ideally transparent (so that you could better see the target surface).  The gasket has to be made out of 100% TPU — it holds teeth (burs) in place once the cap is tightened.

Assembly

1. Slide small metal drill bits into the holes;

2. Attach the bolt, nut, and washer to the shaft platform and tighten them well;

3. Add shape-defining platform at the base of the bits (optional);

4. Tighten the round cap;

Usage

1. Secure the nut (shaft) inside your drill's/grinder's chuck;

2. Use bushing to ensure 90º alignment with the surface (optional);

3. Set your drill's direction to CW, and start carefully cutting the target surface;