Follower arm · Step 24 of 26 · F-063

Install the gripper claw

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Slide the gripper claw down into the slot in the gripper body from the top, so it stands at a right angle to the body.
src
- orientation note — Perpendicular to the gripper body, slid in from the top (Waveshare).
- waveshare.com — Follower step 18: slide F10 from top to bottom into the F9 slot
- parts.yaml · moving-jaw-so101 — Moving jaw (gripper claw)
Screw it on with 4
M3x6
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
on each side.
src
- lerobot/docs/source/so101.mdx#gripper--handle — Follower: "Install the gripper claw and secure it with 4 M3x6mm screws on both sides."
- check — 4 M3x6 on both sides; claw slid into the slot from the top.

Done when The claw is in its slot from the top, with 4 screws on each side.

lerobot/docs/source/so101.mdx#gripper--handleFollower: "Install the gripper claw and secure it with 4 M3x6mm screws on both sides."

waveshare.comFollower step 18: slide F10 from top to bottom into the F9 slot

Orientation: Perpendicular to the gripper body, slid in from the top (Waveshare).

Check: 4 M3x6 on both sides; claw slid into the slot from the top.

Motor slot: gripper · ID 6 · STS3215 1:345 · 7.4V servo on a 5V supply; 12V servo on a 12V 5A+ supply (optional variant);

The motor you labelled 6: STS3215 motor,

1:345

Gear ratio. The number on the motor's label, such as 1:345. The motor inside turns 345 times for one turn of the output. The follower arm uses 1:345 at all six joints. The leader arm mixes 1:191, 1:345 and 1:147, so check the label before fitting a motor.Source: lerobot/docs/source/so101.mdx#step-by-step-assembly-instructions · SO-ARM100/README.md#sourcing-parts

gear, code C001. details

Gripper claw (the moving jaw)Moving jaw (gripper claw) moving-jaw-so101 details
STS3215 motor, 1:345 gear, code C001Feetech STS3215 servo, 7.4V, 1:345 gear (C001) servo-sts3215-c001-345
approximation3D stand-in
Stand-in shape: the 3D geometry or placement is not measured from the real part.
Qty 7 is the two-arm build (6 follower + 1 leader). A 12V variant with 30 kg.cm stall exists for the follower only and needs a 12V 5A+ supply (README). Includes two horns and a 3-pin cable per the assembly texts; kit contents are not itemised upstream. Geometry: the upstream repo's own simplified body `STEP/SO100/STS3215_03a.step` (Apache-2.0, single solid drawn to the datasheet, D-007 for where they differ) with its fused horn plates cut off and the datasheet ø6 x 3.4 output boss added, posed on the embedded vendor model's transform; the vendor mesh is not redistributed.
details
M3x6 screwM3x6 screw m3x6 ×8 details
Phillips screwdriver #0 · PH0 tool details
Phillips screwdriver #1 · PH1 tool details

Sources (2)

lerobot/docs/source/so101.mdx#gripper--handle — Follower: "Install the gripper claw and secure it with 4 M3x6mm screws on both sides."
waveshare.com (retrieved 2026-09-07) — Follower step 18: slide F10 from top to bottom into the F9 slot