Hose barbs for 2, 3, 4, 6 and 8 mm ID tube — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/hose-barbs/  (CC BY 4.0)
Basis: Barb geometry rule: shank Ø = tube ID, three 2.5 mm ramps to tube ID + 1.2 (the designed stretch), hex base AF = ID + 6
Catalog version: 2026-10-20

Sizes: see table below
- Each barb has a 14 mm shank at the tube ID, three ridges (at 2, 6 and 10 mm from the tip) that ramp over 2.5 mm from the ID to ID + 1.2, and a 4 mm hex base; overall 18 mm.
- Sizes: 2 mm (ridges Ø3.2, Ø1 bore, 8 AF), 3 mm (Ø4.2, Ø1.5, 9 AF), 4 mm (Ø5.2, Ø2.5, 10 AF), 6 mm (Ø7.2, Ø4.5, 12 AF), 8 mm (Ø9.2, Ø6.5, 14 AF).
- The +1.2 on the ridges is the designed stretch of the tube; the shank is the tube ID, exact.
- The can-engine cap's transfer port is an integral Ø4 barb with the same profile as barb-4mm.

barb  shank_mm  ridge_mm  bore_mm  hex_af_mm
barb-2mm  2  3.2  1  8
barb-3mm  3  4.2  1.5  9
barb-4mm  4  5.2  2.5  10
barb-6mm  6  7.2  4.5  12
barb-8mm  8  9.2  6.5  14

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: Hose barb — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Hose_barb
- Wikipedia: Push-fit fitting — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Push-to-connect_fitting
- McMaster-Carr: Tubing (free STEP per part, for your own design use; no redistribution) — STEP, PDF — McMaster-Carr site terms [verify license at link] — https://www.mcmaster.com/products/tubing/
- Long Earth Society: Engine and rig builds — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 5 parts): https://xemstudio.com/files/hardware/hose-barbs/index.json
API: https://xemstudio.com/api/geometry?object=hose-barbs