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Insert the gripper motor and fit its horn unverifiedno source yet Unverified. Part of this step is not confirmed by any public source yet (see the sources below). Follow the upstream video for this joint and report what you find.
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Take the motor you labelled 6. src servos.yaml · leader/gripper — ID 6 · STS3215 1:147 · Feetech STS3215 servo, 7.4V, 1:147 gear (C046) F-002 · check — Each motor answers on its own ID 1–6, bottom joint = 1, gripper = 6; leader and follower motors are labelled and kept apart. Slide it into the leader holder and fix it with 2 small self-tapping screws Self-tapping screw. A screw that cuts its own thread into the plastic as you drive it. These are the smallest screws in the kit and hold each motor in its printed bracket. No public source confirms the exact size yet (D-001).Source: lerobot/docs/source/so101.mdx#joint-1 · waveshare.com src Fit the geared horn Horn. The metal disc that fits on the end of a motor; printed parts screw onto it. Each motor ships with two, one with gear teeth around its edge for the driven end and one plain disc for the other end.Source: waveshare.com · lerobot/docs/source/so101.mdx#joint-1 M3x6 screw. M3x6. A screw size. M3 means a 3 mm thread, 6 means 6 mm long. It has a machine thread and goes into the threaded holes of a horn; the same size holds each printed part to its horn.Source: mantech.co.za · lerobot/docs/source/so101.mdx#joint-1 src lerobot/docs/source/so101.mdx#gripper--handle — Leader: "Insert the gripper motor, secure it with 2 M2x6mm screws on each side, attach a motor horn using a M3x6mm horn screw." waveshare.com — Leader step 17: "the steering wheel is installed at both ends of the servo" instructions — LeRobot says "attach a motor horn"; Waveshare fits horns at both ends. Both listed; see D-006. Part identity inferred from STL file name (see part notes); confirmed only when Phase 2 places it in the assembly STEP. check — 2 M2x6 on each side; horn retained by its M3x6; cable connects to motor 5. Connect motor 6 to motor 5 with its cable. src check — 2 M2x6 on each side; horn retained by its M3x6; cable connects to motor 5. servos.yaml · leader/gripper — ID 6 · STS3215 1:147 · Feetech STS3215 servo, 7.4V, 1:147 gear (C046) Done when 2 screws on each side, the horn held by its screw, and the cable goes to motor 5.
lerobot/docs/source/so101.mdx#gripper--handle Leader: "Insert the gripper motor, secure it with 2 M2x6mm screws on each side, attach a motor horn using a M3x6mm horn screw." waveshare.com Leader step 17: "the steering wheel is installed at both ends of the servo" Notes: LeRobot says "attach a motor horn"; Waveshare fits horns at both ends. Both listed; see D-006. Part identity inferred from STL file name (see part notes); confirmed only when Phase 2 places it in the assembly STEP.
Check: 2 M2x6 on each side; horn retained by its M3x6; cable connects to motor 5.
Motor slot: gripper · ID 6 · STS3215 1:147 ·
7.4V servo on a 5V supply;
You need STS3215 motor, 1:147 gear, code C046 Feetech STS3215 servo, 7.4V, 1:147 gear (C046) servo-sts3215-c046-147 approximation3D stand-in Stand-in shape: the 3D geometry or placement is not measured from the real part.
Geometry: the upstream repo's own simplified body STEP/SO100/STS3215_03a.step (Apache-2.0, D-007) with its fused horn plates cut off and the datasheet ø6 x 3.4 boss added, posed on the embedded vendor model's transform; the vendor mesh is not redistributed.
details Leader holder Leader wrist roll (leader holder) wrist-roll-so101 details Horn with gear teeth (drive end) Servo horn, geared (drive side) servo-horn-geared approximation3D stand-in Stand-in shape: the 3D geometry or placement is not measured from the real part.
Ships with the servo. "Each servo is equipped with two steering wheels, one with gears and the other without" (Waveshare). Qty = one per servo for two arms. Geometry: drawn from the datasheet Accessories drawing: ø19.95 plate 2.5 thick, ø9 hub to 4.5 overall, ø3.2 centre bore, 4-M3 on ø14; the plate outline is drawn as the circle (the drawing shows a polygon whose side count is not dimensioned) and the 25T spline is not modelled. Placed on the embedded vendor horn's transform; the vendor mesh is not redistributed.
details Horn without teeth (idle end) Servo horn, plain (idle side) servo-horn-plain approximation3D stand-in Stand-in shape: the 3D geometry or placement is not measured from the real part.
Ships with the servo. Not fitted on motor 5 (one horn only) on either arm, hence 10 for two arms. Geometry: drawn from the datasheet Accessories drawing: ø19.95 plate 2.1 thick, ø9 hub to 3.1 overall, ø6.05 centre bore, 4-M3 on ø14; outline drawn as the circle. Placed on the embedded vendor horn's transform; the vendor mesh is not redistributed.
details Small self-tapping screw (motor screw) Motor-tab screw, M2-class self-tapping motor-tab-screw unverifiedno source yet Not checked yet: no public source confirms this. Treat it as a best guess and report what you find.
Sources disagree and no kit has been measured (D-001, open). Upstream default = the assembly STEP, which models 24 positions per arm: 22 x "Type I Cross Recessed Fillister Head Tapping Screw ANSI B18.6.4 1-42 x 0.1875 Type AB" (≈ ø1.9 x 4.8 mm) and, for the two screws that enter motor 1 from above, 2 x "0-48 x 0.1875" (≈ ø1.5 x 4.8 mm). Vendor/doc variants: LeRobot "M2x6mm screws (smallest screws)"; Waveshare "pointed screws". The Feetech datasheet gives no tab screw and ships "No Accessories". Qty = count used across the LeRobot steps (24 + 21 positions); a kit inventory settles the spec and count. Seating per screw is read from the STEP by the pipeline (shank through a hole of which printed part) and drives what the 3D view shows at each step.
×4 details M3x6 screw M3x6 screw m3x6 ×1 details Phillips screwdriver #0 · PH0 tool details Phillips screwdriver #1 · PH1 tool details Cables in the 3D view motor 5 → motor 6 wrist roll → gripper cable-wrist-roll-to-gripper approximation3D stand-in Stand-in shape: the 3D geometry or placement is not measured from the real part.
Sources (2) lerobot/docs/source/so101.mdx#gripper--handle — Leader: "Insert the gripper motor, secure it with 2 M2x6mm screws on each side, attach a motor horn using a M3x6mm horn screw." waveshare.com (retrieved 2026-09-07) — Leader step 17: "the steering wheel is installed at both ends of the servo"