Rhombic frame head for the 2 in tri-clamp beta: gear-shaft walls on a clamp-on cap — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/rhombic-frame-head/  (CC BY 4.0)
Basis: ISO 2852 cap face; 625 bearing (5 × 16 × 5) pockets on the rhombic gear centre distance 66; heights and planes from the rhombic kinematics in tools/rhombic_geom.py
Catalog version: 2026-10-20

Sizes: see table below
- An ISO 2852 cap face for the 2 in ferrule, a Ø50.8 pedestal clear of the clamp, and a 96 × 87 × 4 platform at 14 mm with a Ø24 rod window on the spool axis.
- Two walls, 5 mm thick and 96 wide, stand on the platform behind the spool axis (y -31..-26 and -61..-56); each has two Ø16 through pockets for 625 bearings (fit: press) at x ±33, 62 mm above the face: the two Ø5 gear shafts, 66 mm apart, the meshing distance of the module 1.5 × 44 T gears.
- The gears hang in front of the front wall on the shaft ends; links and yokes are in front of them on the rod axis. At 62 mm the gears, the lower links and the lower yoke all stay above the platform through a full turn.
- The rear wall's shaft collars and the 1 mm spacers between gear hubs and front bearings hold each shaft axially.

feature  size_mm  position_mm
ISO 2852 face  2 in (Ø64 rim)  z 0
platform  96 × 87 × 4  z 14..18
walls  96 × 5, to z 75  y -31..-26, -61..-56
625 pockets  Ø16 through  x ±33, z 62
rod window  Ø24  on the axis

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

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/rhombic-frame-head/index.json
API: https://xemstudio.com/api/geometry?object=rhombic-frame-head