Very happy with this creation, it's a 35:1 print-in-place dual stage planetary gear system (sun 1 : ring 2). The really cool thing is that the rings won't shift without the inner gears being turned, so no back-driving; the arms are locked if the dial isn't turned.

Saw the 'Falcon Clamp' by tmackay on TeachingTech and realized I could make something similar - but more to my liking. I used:

• Satisfying Dual Stage Planetary Gears OpenSCAD script by Snaxxus to generate the gears.

• Print In Place PCB-Holder / Gripper by Turbo_SunShine for the arms.

• Sketchup 8 to put it all together.

PRINT INSTRUCTIONS

• 0.4mm nozzle

• 0.2mm layer height

• 3 perimeters

• 5 layers top and bottom

• 15% infill

• no supports

For ‘cracking’ the print for the first time, I insert a scraper between the top and bottom rings to separate them apart - I find this manages to take care of the majority of the needed ‘cracking’.

Thanks to the suggestion by Joe Programmer; the upper sun gear is now supported off a post that comes up through the lower sun gear. I've only made this edit to the version of the clamp with a Hex-dial. The first layer of the support post and the bottom sun gear are connected with tabs to ensure adhesion to the build plate. That's what I cut post-print in the above video.

DIALS

rev 3

Rounded Hex-Dial for improved grip while maintaining ease of rotation.

rev 2

Improved grip via a Tri-Dial. 

rev 1

Original design came with a simple Round Dial.

STANDS

Honestly, I've come to find that designing a suitable stand for my Mantis Clamp to be one of the biggest challenges for this project.

rev 5

Tension Stand generated with slightly deeper part trays and a ‘jaw’ that is 0.5mm smaller than the mantis clamp. Thus, the ‘jaw’ has to flex open to grip the clamp in position.

rev 4

Wedge Stand added based on TeachingTech's comments about the Mantis Feet not working out so well. Uses a progressively tighter grip socket to hold the Mantis Clamp in place with friction. Bonus: includes two small and shallow part trays!

rev 3

New stand concept that I've dubbed Mantis Feet (super original, I know). Note that these do not work with the version(s) of the Mantis Clamp that have removable supports under the arms.

rev 2

Version of the stand with PiP locking functionality! I print the locking stand at 100% infill. As well, there's a little bit of built-in support at the top end of the locking mechanism barrel that needs to be snipped off post-print.

EDITS

[2025-01-13] I've designed a new version of the clamp with hinged pads at the tip that allow for secure holding of small PCBs. I call this version the Mandible Clamp … just because. 

[2025-01-10] Thanks to various upgrades to my 3D printer (and PrusaSlicer's Arachne engine) I've successfully printed the 0.10mm backlash model, it's no longer experimental :) 

[2024-05-03] Thanks to discussions with @VaguelyUseful, I've now also added an experimental version of the Mantis Clamp that reduces the backlash down to 0.10mm. Good luck to those who attempt this version!

[2023-03-10] Owing to several comments that there's too much play (backlash) in the gears, I've uploaded a version of the Mantis Clamp that reduces the backlash from 0.25mm to 0.20mm. I still recommend the 0.25mm backlash though - to better avoid a fused print.

[2023-02-23] In response to Invalid_Maus's comment about the round dial version of the Mantis Clamp still having removable supports under the arms, I've uploaded a new file that turns the supports into a strengthening feature of the arms instead.

BONUS

OMG!!! TeachingTech talked about the Mantis Clamp!!!