Update 4/17/17 - I have added a center beam for non-conductive plastic which removes the countersinks for the threaded inserts. I have also tweaked the conductive plastic design to slightly reduce the threaded insert countersink. I noticed some were loose after cleanup.

This was inspired by NA8E's morse code key http://www.thingiverse.com/thing:630117. I created this in Solidworks from scratch and went through 4-5 versions before settling (for the moment) on this one.

Similar to the NA8E key this one uses bearings and a precision fit shoulder bolt to support the main beam for smooth operation. This one uses all brass 4-40 hardware and brass inserts for the plastic to keep from stripping out or pulling out.

Another feature of this key is the center beam can be printed from conductive plastic to make connections to the top contact at the rear of the beam. It also has gap adjust and spring tension adjust.

The hardware necessary for this includes:
2 686-ZZ Bearings 13mm OD, 6mm ID, 5mm Thick
1 6mm dia x 45mm shoulder bolt
1 M5 x 0.8 nylon insert nut (McMaster 90576A104)
4 4-40 narrow brass hex nuts (McMaster 95130A110)
3 Screw to expand brass inserts for 4-40 (McMaster 92395A315)
1 4-40 round head brass 5/16" screw (McMaster 94070A107)
1 4-40 round head brass 5/8" screw (McMaster 94070A112)
2 4-40 round head brass 1" screw (McMaster 94070A115)

Check my personal site K5ABL.com for availability of printed keys, customized keys with call sign and hardware kits only.