Oblong endless rack and pinion (mangle rack) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/mangle-rack-oblong-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design following Brown No. 119 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- The rack is an endless oblong loop of teeth; the pinion, turning always the same way, meshes with the top straight and drives the rack one way, rolls round the half-gear end and comes back along the bottom straight driving it the other way. Its shaft moves up and down 20 mm in a slot as it changes sides.
- Module 1, 20 T pinion; straights 12.57 mm: the rack bar's stroke is the straight length plus the end travel. Drawn with the pinion mid-way along the top straight, its Ø6 axle in the 6.2 mm slot of the catalog guide plate (slot turned vertical).
- Brown's No. 119 (oblong endless rack on a bar, pinion shaft guided by a slotted bar); the mangle rack of Nos. 197–199 is the same idea in a frame.
- Parts (each has its own page): oblong-endless-rack-m1-20t-ends, spur-gears-module-1, slot-guide-plate-90, dowel-pins-metric.
- Brown's movement No. 119 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
pinion  20 T, module 1, Ø6 axle
rack straights  12.57 mm
shaft travel  20 mm, in a 6.2 slot
rack stroke  ≈ 32.57 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. 119: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_119.html

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/mangle-rack-oblong-mechanism/index.json
API: https://xemstudio.com/api/geometry?object=mangle-rack-oblong-mechanism