Heads up: many models on this page are AI-generated or uploaded untested. They may be misconfigured for the intended application — check the dimensions and tolerances, and verify or edit the model before printing or relying on it.*
SG90 Twin-Groove Tendon Spool
A two-groove tendon spool that screws onto an SG90/MG90S servo horn. It pulls a flexor line in one groove and lets out an extensor line in the other, so one servo drives a tendon finger both ways. It is 37 mm across and 22 mm tall, with 16 mm drums, a Ø7.5 mm bore so a screwdriver reaches the horn screw, a Ø9 mm recess for the horn hub, M2 clearance holes at radii of 12 and 15 mm on four arms, and Ø1.6 mm tie-off holes.
Four-Finger Palm With Thumb Clevis
The palm of the 'SG90 Tendon-Driven Robot Hand' kit. It is a 90 x 80 x 8 mm plate with a thenar lobe that bolts to the Five-Servo Forearm Deck with 4x M3x16 bolts and nuts through Ø3.4 mm holes. Four finger knuckle clevises and one side thumb clevis each take an M3x20 socket head bolt and nylock nut as the pin, with 6.6 mm gaps for the 6 mm digit tongues. Extensor grooves are cut into the underside and slotted flexor ribs sit on top at 17 mm, so the 0.5 mm nylon tendons run to each finger at their fixed heights.
Wrist Tendon Guide Comb
Upright 80 x 20 x 24 mm comb for the 'SG90 Tendon-Driven Robot Hand' kit. It bolts to the Five-Servo Forearm Deck with 2x M3x10 bolts and nuts through Ø3.4 mm holes at (112, ±20), and runs 10 tendons of 0.5–0.8 mm nylon line through Ø2.0 mm guide holes. The guide holes sit at the flexor height (17 mm) and extensor height (5 mm) for each finger lane. Each hole has a 45° countersink widening to Ø5 on the spool side, so lines that come in at an angle don't fray on a sharp printed edge.
Five-Servo Forearm Deck
A 150 x 166 mm ribbed forearm deck that holds five SG90-class micro servos side by side at 36 mm pitch to drive the tendons of a five-finger robot hand. It has 23.4 x 12.6 mm servo pockets with open ear slots that accept a range of M2 tab-screw spacings, M3 clearance holes (3.4 mm) for a tendon comb and wrist mount, a 32 mm skirt with a 2 mm wall, and a cable notch.