Rolling parallel ruler blade 200 × 24 × 6 with lugs for a Ø3 axle — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/rolling-ruler-blade-200-d18/  (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 200.0, width 24.0, height 13.0
- 200 × 24 × 6 straight-edge with four lugs holding a Ø3 axle 8 mm above its underside and two 5 × 20 openings at x = ±60 (5 along the blade) through which the Ø18 rollers reach 1 mm below the blade; the rollers' rims do the guiding, the blade's long edges do the drawing.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
blade  200 × 24 × 6 mm
axle holes  Ø3, centre 8 mm above the underside
roller openings  2 × 5 × 20 mm at x = ±60
lugs  4 × 6 × 10 × 7 mm

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. 323: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_323.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/rolling-parallel-ruler-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/rolling-ruler-blade-200-d18/index.json
API: https://xemstudio.com/api/geometry?object=rolling-ruler-blade-200-d18