Stirling shafts and rods: Ø3 rods, Ø5 / Ø8 D-flat crankshafts, Ø5 tube rods, Ø3 pins, thrust spacers — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/stirling-shafts-and-rods/ (CC BY 4.0) Basis: The shelf's interfaces: Ø3 displacer rods and pins, Ø5 shafts in 625 bearings, Ø8 in 608s, 5 mm tube piston rods with a Ø3.4 bore; D-flat 0.5 mm as on motor shafts so grub screws bite and the shaft cannot slip Catalog version: 2026-10-20 Sizes: see table below - Every rod here is a solid model: you choose walls and infill. For shafts that carry load (crankshafts, pins) print 100 % infill or 6+ walls, lying flat (the D-flat side down on the bed gives a flat, accurate grub face and puts the layers along the shaft, which is how it bends). - Which rod goes where: Ø3 rod: displacer rod from the displacer cap through the guide, bushings or the piston's crown bushing to the rod clevis or rhombic upper yoke. Ø3 crankshaft: in the crank head's 623 towers with the Ø3-bore crank discs. Ø5 D-flat: in the 625 crank stands and rhombic plates, carrying crank discs and the nut flywheel (b5). Ø8 D-flat: in the tri-clamp crank frame's 608s with the crank webs and flywheels (b8). Ø5 tube: piston rod from the piston plug, around the displacer rod. Ø3 pins: crank, wrist and link pins. - Printed Ø5 / Ø8 crankshafts in bearings run fine at a few hundred rpm. - Thrust spacers set the 1 mm gaps along the shaft (tower · web · rod · web · tower · flywheel): stack 1, 2, 3 and 5 mm pieces to fill a gap. - Lengths: 2 in gamma crankshaft Ø5 × 100 between two 625 stands with the flywheel outside; tri-clamp crank frame Ø8 × 80; rhombic gear shafts Ø5 × 80 (one × 120 to carry the flywheel); displacer rod = displacer cap to clevis plus stroke, cut a 150 or 200 to length. - LES: the shafts the engines turn on. part dia_mm length_mm feature fits steel equivalent Ø3 rod 3.0 100 — displacer rod; rod clevis; displacer cap music wire / drill rod Ø3 h6 Ø3 rod 3.0 150 — displacer rod; rod clevis; displacer cap music wire / drill rod Ø3 h6 Ø3 rod 3.0 200 — displacer rod; rod clevis; displacer cap music wire / drill rod Ø3 h6 Ø3 crankshaft 3.0 40 — crank head 623s; crank-disc-b3 drill rod Ø3 Ø3 crankshaft 3.0 60 — crank head 623s; crank-disc-b3 drill rod Ø3 Ø3 crankshaft 3.0 80 — crank head 623s; crank-disc-b3 drill rod Ø3 Ø5 crankshaft 5.0 80 D 0.5 625 stands; rhombic gears; crank discs; flywheel b5 Ø5 h6 ground rod Ø5 crankshaft 5.0 100 D 0.5 625 stands; rhombic gears; crank discs; flywheel b5 Ø5 h6 ground rod Ø5 crankshaft 5.0 120 D 0.5 625 stands; rhombic gears; crank discs; flywheel b5 Ø5 h6 ground rod Ø5 crankshaft 5.0 150 D 0.5 625 stands; rhombic gears; crank discs; flywheel b5 Ø5 h6 ground rod Ø8 crankshaft 8.0 80 D 0.5 crank frame 608s; crank webs; flywheel b8 Ø8 h6 rod Ø8 crankshaft 8.0 100 D 0.5 crank frame 608s; crank webs; flywheel b8 Ø8 h6 rod Ø8 crankshaft 8.0 120 D 0.5 crank frame 608s; crank webs; flywheel b8 Ø8 h6 rod Ø5 tube rod 5.0 80 Ø3.4 bore piston plug; rhombic lower yoke; flexure stack A K&S 5 mm brass tube Ø5 tube rod 5.0 120 Ø3.4 bore piston plug; rhombic lower yoke; flexure stack A K&S 5 mm brass tube Ø5 tube rod 5.0 160 Ø3.4 bore piston plug; rhombic lower yoke; flexure stack A K&S 5 mm brass tube Ø3 pin 3.0 12 — crank / wrist / link pins dowel 3 m6 Ø3 pin 3.0 16 — crank / wrist / link pins dowel 3 m6 Ø3 pin 3.0 19 — crank / wrist / link pins dowel 3 m6 Ø3 pin 3.0 20 — crank / wrist / link pins dowel 3 m6 Ø3 spacers 3 1 / 2 / 3 / 5 — between bearings, webs, rods, flywheel washers Ø5 spacers 5 1 / 2 / 3 / 5 — between bearings, webs, rods, flywheel washers Ø8 spacers 8 1 / 2 / 3 / 5 — between bearings, webs, rods, flywheel washers 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, 32 parts): https://xemstudio.com/files/hardware/stirling-shafts-and-rods/index.json API: https://xemstudio.com/api/geometry?object=stirling-shafts-and-rods