Kitsmith SO-101

Bill of materials

Quantities are for the two-arm build unless a part says otherwise. Names match the upstream STL/STEP files; vendor numbers are on the kits page.

Printed parts

PartQtyArmsAlso known as
Base 1follower, leaderbase; base F1 (Waveshare)
Base motor holder 1follower, leaderBase_08p; first motor holder (LeRobot); base motor bracket F2 (Waveshare)
Motor holder (base side) 1follower, leadershoulder motor holder (LeRobot); shoulder motor bracket F4 (Waveshare)
Motor holder (wrist side) 1follower, leadermotor holder 4 (LeRobot); elbow motor bracket F7 (Waveshare)
Under arm (forearm) 1follower, leaderforearm (LeRobot); forearm F6 (Waveshare)
Upper arm 1follower, leaderupper arm (LeRobot); upper arm F5 (Waveshare)
Rotation/pitch (shoulder) 1follower, leadershoulder part (LeRobot); shoulder F3 (Waveshare)
Wrist roll/pitch (wrist holder) 1follower, leaderWrist_Roll_Pitch_SO100; wrist holder (LeRobot); wrist bracket F8 (Waveshare)
WaveShare controller mounting plate 1follower, leaderdriver board bracket F11 / L12 (Waveshare)
Seeed Studio controller mounting plate unverifiedno source yet1follower, leader
Leader handle approximation3D stand-in1leaderhandle (LeRobot); Leader joystick L11 (Waveshare)
Leader trigger 1leaderfollower trigger (LeRobot); Leader trigger L10 (Waveshare)
Leader wrist roll (leader holder) 1leaderleader holder (LeRobot); Leader wrist L9 (Waveshare)
Moving jaw (gripper claw) 1followergripper claw (LeRobot); Follower gripper F10 (Waveshare)
Follower wrist roll (gripper body) 1followergripper (LeRobot, Gripper/Handle step 1); Follower wrist F9 (Waveshare)

Servo parts

PartQtyArmsAlso known as
Feetech STS3215 servo, 7.4V, 1:345 gear (C001) approximation3D stand-in7follower, leaderST3215 Servo; SCS215
Feetech STS3215 servo, 7.4V, 1:191 gear (C044) approximation3D stand-in2leaderST3215 Servo; SCS215
Feetech STS3215 servo, 7.4V, 1:147 gear (C046) approximation3D stand-in3leaderST3215 Servo; SCS215
Feetech STS3215 servo, 12V, 1:345 gear (optional follower variant) approximation3D stand-in0followerST3215 Servo; SCS215

Electronics parts

PartQtyArmsAlso known as
Motor control board (Waveshare bus servo adapter) approximation3D stand-in2follower, leader
Power supply, 5V (for 7.4V servos) 2follower, leader

Hardware parts

PartQtyArmsAlso known as
Servo horn, geared (drive side) approximation3D stand-in12follower, leader
Servo horn, plain (idle side) approximation3D stand-in10follower, leader
Table clamp 4follower, leader

Cable parts

PartQtyArmsAlso known as
USB-C cable 2follower, leader
3-pin servo bus cable unverifiedno source yet6follower, leader

Fasteners

IdSpecQtyWhere used
m2x6 M2x6 screw1Handle to leader holder (LeRobot: "1 M2x6mm screw").
notesOnly the handle screw keeps this id. Motor-to-bracket screws are motor-tab-screw (D-001, open). Its hole is known: Handle_SO101.step and Wrist_Roll_SO101.step share one authoring frame, and the handle's single r=1.1 (M2 clearance) hole lies on the axis of an r=0.6 pilot hole in the holder (D-005).
Sources (3)
motor-tab-screw unverifiedno source yetMotor-tab screw, M2-class self-tapping45Servo body to printed brackets: 4 per motor, 2 for motor 5 (22 per arm), plus the two that hold the base motor holder to the base (LeRobot "one on each side"; they thread into the base, not the servo). 24 per arm.
notesSources 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.
Sources (4)
m3x6 M3x6 screw96Horn retaining screw (one per driven horn) and printed part to servo horn.
notesQty = count used across the LeRobot steps (follower 50 + leader 46). Horn screw confirmed by the Feetech datasheet drawing ("M3X6 machine-thread screw" at the 25T output). The assembly STEP models 45 "DIN EN ISO 7045 - M3 x 6" pan-head screws: 40 printed-part-to-horn (4 per horn side) and one horn-retaining screw (motor 5); the other five horn screws are not modelled, so the pipeline adds one on each geared horn axis (approximation).
Sources (4)
m2.5x4 unverifiedno source yetM2.5x4 pan-head screw (ISO 7045)4Controller board to its mounting plate, with the M2.5 spacers (STEP only).
notesOnly source is the assembly STEP; no assembly text mentions them. The M2.5x4 screws earlier logged under D-001 are these, not motor screws.
Sources (1)
spacer-m2.5-h6 unverifiedno source yetHex spacer M2.5 female-female, 6 mm, pass-through4Between controller board and mounting plate (STEP only).
Sources (1)
m3-nut unverifiedno source yetM3 hex nut2Two nuts modelled in the assembly STEP, seated in pockets of the follower gripper body on its drive-horn side, 8 mm apart below the claw screws; no text describes their use, and no step lists them.
Sources (1)
  • SO-ARM100/STEP/SO101/SO101 Assembly.step — Hexagon Nut DIN 934 - M3 and DIN 555 - M3, one each; placement check: both inside Wrist_Roll_Follower_SO101 pockets (pipeline hole test), absent from the leader holder