Copper pipe (ASTM B88 Type L and M), 1/4 to 2 inch — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/copper-pipe-type-l-m/  (CC BY 4.0)
Basis: ASTM B88: OD = nominal + 1/8 in for all types; Type L and Type M wall thicknesses
Catalog version: 2026-10-20

Sizes: see table below
- OD is nominal + 1/8 in: 1/2 in pipe is 15.88 mm (0.625 in), 3/4 in is 22.22 mm, 1 in is 28.58 mm. Fittings grip the OD; a printed adapter that slips over the pipe uses OD + 0.3 mm.
- Type L (blue) wall: 1/2 1.02, 3/4 1.14, 1 1.27 mm. Type M (red) is thinner: 0.71, 0.81, 0.89 mm. Type K (green) is thicker still and rarer.
- Why it's here: copper's conductivity makes 3/4 and 1 in Type L tube the hot and cold heat-exchanger walls on the LES Stirling heads; 1/4 and 3/8 are regenerator and transfer tubes.

nominal_in  od_mm  type_l_wall_mm  type_l_id_mm  type_m_wall_mm  type_m_id_mm
1/4  9.53  0.76  8.01  0.64  8.25
3/8  12.7  0.89  10.92  0.64  11.42
1/2  15.88  1.02  13.84  0.71  14.46
3/4  22.22  1.14  19.94  0.81  20.6
1  28.58  1.27  26.04  0.89  26.8
1-1/4  34.93  1.65  31.63  1.07  32.79
1-1/2  41.28  1.52  38.24  1.24  38.8
2  53.98  1.78  50.42  1.47  51.04

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: Copper tubing — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Copper_tubing
- Copper Development Association: Copper Tube Handbook (dimensions table) — PDF — CDA publication [verify license at link] — https://www.copper.org/publications/pub_list/pdf/copper_tube_handbook.pdf
- Long Earth Society: Engine builds that use these parts (videos and write-ups) — 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/copper-pipe-type-l-m/index.json
API: https://xemstudio.com/api/geometry?object=copper-pipe-type-l-m