This 3D model uses readily available replacement parts for rotary knife sharpeners (such as those from Horl) to cost-effectively build your own rotary knife sharpener.

• Plate1 – The rotary sharpener itself, printed without supports but assembled from two parts using adhesive and clips
• Plate2 – The same design as a single solid object, printed with supports (which can be tricky when printing threaded features) – not yet tested (feedback welcome)
• Plate3 – Knife holder at 20° – the standard angle for knives in Europe (robust)
• Plate4 – Knife holder at 10° – extra sharp but more delicate
• Plate5 – Knife holder at 15° – the compromise between 20° and 10°

Replacement discs are required for the rotary sharpener; for example, you can find a “rotary sharpener replacement disc set” on Amazon for just under €10.

The knife holders have a high side and a low side, with the latter designed for narrow blades.

Fifteen magnets, each 6 mm in diameter and 2 mm thick, are needed for the knife holder.

Underneath the knife holder, there are cutouts for anti-slip rubber pads (e.g., those used on Ikea cabinet doors; hot glue works as well).

Caution

Rotary knife sharpeners like the one from Horl use ball bearings. This means the discs rotate, but the roller/handle itself does not; the handle is held stationary.

In my version, however, the handle rotates along with the discs. This approach also works and is significantly cheaper to build.