Biegelehre Improved - Through-hole component lead bending tool

Accurately bending leads on radial, through-hole components like capacitors and resistors has never been this fun! :D

Inspired by the fancy tools used by the talented Marco Reps in his GPS Nixie Clock video, I modeled a Biegelehre from scratch with some minor improvements from the standard injection-molded original form.

Improved? How?

Glad you asked! I've used an injection-molded version I found on eBay for a few years now and its pretty great, with a few quirks.

1. Bending leads at the same points was easy, bending leads straight and parallel not so much
2. The wider area sometimes didn't have the depth required for components with larger diameters, like big diodes

To address these two I made two changes.

1. Added “slots” along the sides for component leads, making parallel bending a lot easier
2. Increased the ‘depth’ of wider component segments while retaining rigidity

Some other tweaks were made for usability and general printability

1. Base supports were modified to expand from a thinner profile, making the underside much more printable by FFF printers
   • These changes may not be as useful/desirable for SLA printing, but they work great for FFF prints
2. Fine detailing was added to the individual lead slots to round them out a bit, helping leads find a center rather than just floating in the squared off bases
   • Test prints showed that these chamfers make pin bending a bit nicer when printed at 0.1 layer heights but they're barely noticable at larger layer heights

Otherwise, this model is very similar to the classic, well-worn (and super useful) design.

Printing Notes

All test prints were made with Prusament PETG on a Prusa MINI+ with stock firmware and mostly default printer settings in PrusaSlicer 2.4.2. Only perimeters and shell thickness were changed, to ensure rigidity - to 4 perimeters and 0.8mm top/bottom shell thickness respectively. No supports were used.

Printing at 0.1mm is recommended, although it take a lot longer than 0.2 or 0.25mm layer height prints - 6 hours at 0.1 DETAIL vs 2.5 hours at 0.25 DRAFT. I didn't test changing layer heights mid-print, which may actually work really well on this model since the increased layer heights only really matter for the top 5% or so of the layers.

If you find yourself assembling or repairing a lot of through-hole electronics though then I'd say the extra time for a higher detail print is worth it, since it definitely produces a substantially improved print.