Shimano TL-PD63 alternative SPD pedal cone tool

thingiverse

If you've dismantled a set of Shimano M324 pedals and found you really don't want to pay for the special tool to hold the outer cone while you tighten the locknut, give this a try. It's designed to fit as snugly as possible round the 13mm head of the cone and still allow you to get your 10mm socket down the centre to tighten the locknut. I've tried to make it as tight as possible in the recess of the pedal housing to avoid it slipping during use, so depending on your printer accuracy you might need to, er, hammer it on. Bear in mind it is plastic after all, so you might need to print a new one for the other side. I'd suggest a good amount of infill to give it strength. It worked well for me though.