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Step-up gears for a generator inside a 2 in tri-clamp cross: 42 : 15, module 1

Name: Step-up gears for a generator inside a 2 in tri-clamp cross: 42 : 15, module 1 dimension sheet
Creator: Xem Studio
License: https://creativecommons.org/licenses/by/4.0/

How do I speed up a small generator from a Stirling crankshaft inside a 2 inch tri-clamp cross? · Hardware · basis: ISO 53 basic rack (20°, addendum 1 m, dedendum 1.25 m), involute flanks as the spur gears on this site; centre distance m (z1 + z2) / 2; tooth counts set by the room in the cross; rotor-top holes from the 2208 listing

Long Earth Society build part. The gears that turn the generator in my sealed engine. The engines

Exact dimensions. Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part. Mating features

sizes: 3 in table

Notes

The crank gear (42 teeth, tip Ø44) sits on the −X crankshaft beside the crank, in place of one flywheel disc and just as heavy; the 15-tooth pinion turns with the motor's rotor. Centre distance 28.5 mm, ratio 2.8 : 1.
The pinion rides on an adaptor: a Ø18 × 2 flange bolted to the rotor top with four M2 × 4 (their heads on the flange's outer face) and a Ø6 stub through the pinion, which an M3 grub holds. The rotor's holes sit at r 6, inside the pinion's teeth, so the pinion cannot be bolted on directly.
Why 2.8 and not more: the motor's Ø27.5 can lies over the crank, so its axis has to be at least 13 + 13.75 mm above the crankshaft (the crank's con-rod eyes sweep R 13), and the crank gear has to turn inside the Ø47.5 bore. 42 : 15 at module 1 puts the can 1.75 mm clear of the crank and the gear tip 1.75 mm inside the bore.
Both gears are drawn at exact size with no backlash; their teeth are a mating feature (see Mating features).

Sizes

part	teeth	pitch_dia_mm	tip_dia_mm	width_mm	bore_mm
crank gear	42	42.0	44.0	12.0	3.0
pinion	15	15.0	17.0	10.0	6.0
adaptor			18.0	14.0

Mating features

Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.

feature	exact	mates with	fit	files
teeth	module 1, 20°, 42 T and 15 T at 28.5 centre distance, no backlash	each other	designed	all
crank-gear bore	Ø3	Ø3 crankshaft (M3 grub, radial from the rim)	slide	crank-gear-*
pinion bore	Ø6	adaptor stub Ø6 (M3 grub)	slide	pinion-m1-*
adaptor stub	Ø6	pinion bore	slide	pinion-adaptor-*
adaptor flange holes	4 × Ø2.4 on the 12 / 12 pattern	shcs-m2x4 into the motor rotor top	designed	pinion-adaptor-*
grub holes	Ø2.5 (M3 tapped)	set-m3x10 (gear), set-m3x3 (pinion)	designed	crank-gear-*
grub hole	Ø2.5 (M3 tapped)	set-m3x3 onto the adaptor stub (ends at r 6, inside the r 6.25 root)	designed	pinion-m1-*

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

ISO	ISO 53 cylindrical gears, standard basic rack (20°, addendum 1 m, dedendum 1.25 m), as the involute spur gears on this site	standard	dimensions are facts verify
GetFPV (product listing)	Tiger GB2208-80 gimbal motor: 27.5 × 23, 4.5 hollow shaft, stator 4-M3 on 19 × 16, rotor 4-M2 on 12 × 12	web	vendor page; dimensions are facts verify
Long Earth Society	Engine builds	web, video	LES site

Free files

★ Free files 3 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json

crank-gear-m1-42t-b3	crank gear: module 1, 42 teeth, 20° (pitch Ø42, tip Ø44), 12 wide, Ø3 bore, radial M3 tapped hole (Ø2.5) at mid-width	STEP · STL
pinion-m1-15t-b6	pinion: module 1, 15 teeth, 20° (pitch Ø15, tip Ø17), 10 wide, Ø6 bore, radial M3 tapped hole (Ø2.5)	STEP · STL
pinion-adaptor-2208	pinion adaptor: flange Ø18 × 2 with 4 × Ø2.4 on the 12 / 12 rotor pattern, Ø6 stub 12 long	STEP · STL