HTD crank and linkage: webs, link web, con-rods, clevis and Ø12 shafts for a 3 in cross crankcase — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/htd-crank-linkage/  (CC BY 4.0)
Basis: Exact geometry; designed running gaps between every moving plane
Catalog version: 2026-10-20

Sizes: see table below
- Built-up crank on Ø12 shafts in 6001 bearings: web A (displacer throw r 4) – Ø5 pin through the displacer con-rod's 625 – link web – Ø5 pin through the piston con-rod's 625 – web C (piston throw r 20). The displacer pin leads the piston pin by 90°.
- Planes along the shaft (x): web A disc −9.5..−3.5, displacer con-rod −2.5..2.5, link web 3.5..9.5, piston con-rod 10.5..15.5, web C 16.5..22.5: 1.0 between every rod and web (designed). Pins are Ø5 × 16 dowels pressed in the webs.
- Con-rods 60 (displacer, to the clevis on the rod) and 237 (piston, down through the reducer to the piston's cheeks); every eye runs on a 625. Sweep radius 31 (piston eye) inside the 3 in cross bore Ø72.9.

part  role  size
crank-web-r8-b12  displacer web  r 4
crank-web-link-r8-r20  link web  r 4 / 20
crank-web-r20-b12  piston web  r 20
conrod-60-625  con-rod  60.0
conrod-237-625  con-rod  237.0
rod-clevis-6-pin5  rod clevis  Ø6 rod, Ø5 pin
shaft-12x76  shaft  76
shaft-12x210  shaft  210

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 8 parts): https://xemstudio.com/files/hardware/htd-crank-linkage/index.json
API: https://xemstudio.com/api/geometry?object=htd-crank-linkage