Tackle beam 240 × 20 × 12 with Ø3 sockets every 5 mm — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/tackle-beam-240-sockets/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance
Catalog version: 2026-10-20

Overall (mm): length 240.0, width 20.0, height 12.0
- 240 × 20 × 12 bar with a row of Ø3 × 8 deep sockets on one face every 5 mm (x = −115 … 115): block stems and rope ends plug into it at any 5 mm position. Overhead it is the beam; turned over it is the floor plate.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
bar  240 × 20 × 12 mm
sockets  47 × Ø3 × 8 deep, 5 mm pitch

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Henry T. Brown (1868, public domain): Five Hundred and Seven Mechanical Movements — scan on archive.org — web — Publisher's page; dimensions are facts — https://archive.org/details/fivehundredseven00browiala
- 507movements.com: Brown's movement No. 12: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_012.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/single-fixed-pulley-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/tackle-beam-240-sockets/index.json
API: https://xemstudio.com/api/geometry?object=tackle-beam-240-sockets