Sharpness Tester

Compare knife sharpness, similar to (but not the same as!) the Brubacher Edge Sharpness Scale (BESS).

Printing

• Material: PLA
• Infill 15%
• 0.2mm layers
• No supports
• No brim

Parts

• 2 M6 x 25mm Hex bolts (30mm is fine too)
• 2 M6 wingnuts
• 4 M6 washers
• 2 pieces of wire, 3cm long
• 0.2mm monofilament fishing line
• kitchen scale - bonus points if it has a peak hold function

Usage

• Place the monofilament in the gaps, tighten the wingnuts
• There should be a little slack in the monofilament, it should not be tight
• Place the assembly on a kitchen scale, tare 
• Gently place the blade on the monofilament, holding the knife at the tip and the tail
• Slowly increase pressure on the knife, watching the scale
• When the filament breaks, the max readout on the scale is the blade's sharpness
• Test each blade several times at several different points
• Calibrate with a new razor blade and the back of a butter knife
• Keep a small closed container with a small hole in the top to collect filament pieces