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Clearance-seal pistons Ø48.00 × 34 for a bored 2 in spool

Name: Clearance-seal pistons Ø48.00 × 34 for a bored 2 in spool dimension sheet
Creator: Xem Studio
License: https://creativecommons.org/licenses/by/4.0/

What piston fits a 2 inch spool bored to 48 mm? · Hardware · basis: Design values; leakage from plane Poiseuille flow in the clearance (Hagen–Poiseuille)

Long Earth Society build part. My clearance-seal pistons. 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: 2 in table

Notes

Ø48.00 × 34, no rings: the ground OD in the honed Ø48.00 bore is the seal. It is driven through a rod and a crosshead guided outside the cylinder, so it carries no side load and keeps its clearance.
Gamma piston: the Ø8 rod screws into the boss and is locked with an M8 nut on the boss end.
Beta piston: the displacer rod passes through a 6 × 10 × 10 sleeve bushing at the crown (its gland), and the hollow Ø10 piston rod screws into the boss until it bottoms.
Leakage loss in the cycle model (charged air, 600 rpm): 0.46 / 1.56 / 3.70 W at 10 / 15 / 20 µm radial clearance on the gamma.

Sizes

part	od_mm	length_mm	rod
piston-48-gamma-m8	48.0	34.0	M8 socket
piston-48-beta-gland	48.0	34.0	gland + M10 × 1 socket

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
OD	Ø48.00 × 34	honed bore Ø48.00 (clearance seal)	run	all
rod socket	M8 tapped (Ø6.8) z 8–20	Ø8 rod, M8 end	designed	piston-48-gamma*
gland seat	Ø10 × 10 at the crown	6 × 10 × 10 sleeve bushing	press	piston-48-beta*
tube socket	M10 × 1 tapped (Ø9.0) z 14–30	hollow rod, M10 × 1 end	designed	piston-48-beta*

Where the files are

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

Wikipedia	Hagen–Poiseuille equation: annular clearance leakage Q = π D δ³ Δp / 12 μ L	web	CC BY-SA 4.0 (text)
Long Earth Society	Engine builds	web, video	LES site

Free files

★ Free files 2 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json

piston-48-gamma-m8	clearance-seal piston Ø48.00 × 34: crown 6, skirt 3, boss Ø18 with an M8 tapped (Ø6.8) socket z 8–20 for the rod	STEP · STL
piston-48-beta-gland	clearance-seal piston Ø48.00 × 34 for a beta: Ø10 × 10 gland seat at the crown (6 × 10 × 10 bushing, the displacer rod's gland), Ø7 on, M10 × 1 tapped (Ø9.0) socket z 14–30 for the hollow rod	STEP · STL

Plain text: sheet.txt · JSON: /api/geometry?object=clearance-seal-pistons-48

Clearance-seal pistons Ø48.00 × 34 for a bored 2 in spool, isometric render of a generated part — Render of piston-48-beta-gland from the free STEP; not to scale.

Fits with

Free

2 in × 3 in spool with the bore finished Ø48.00 (bored and honed power cylinder), isometric render of a generated part

2 in × 3 in spool with the bore finished Ø48.00 (bored and honed power cylinder)4 sizes★ 1 file Free

Crosshead yokes with a Ø5 stub wrist pin: Ø6, Ø8 and hollow Ø10 rods, isometric render of a generated part

Crosshead yokes with a Ø5 stub wrist pin: Ø6, Ø8 and hollow Ø10 rods3 sizes★ 3 files

Questions

What clearance?

The fit class is a running fit to the honed bore; the leakage table shows what 10, 15 and 20 µm radial cost.