Compression spring OD8, wire Ø1, free length drawn 30 mm, 8 coils — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/compression-spring-od8-wire1-l30/  (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 8.0, width 8.0, height 29.99
- Helical compression spring, Ø8 outside, Ø1 wire, 8 coils, drawn at 30 mm (its working length in the mechanism).
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
OD  8 mm
wire  Ø1
coils  8
length drawn  30 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. 81: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_081.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/mutilated-gear-spring-rack-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/compression-spring-od8-wire1-l30/index.json
API: https://xemstudio.com/api/geometry?object=compression-spring-od8-wire1-l30