Project 003 · Mechanical Design · Precision Machining · Drawing No. SE-001

Stirling
Engine
Design

Recreated a full 39-part Stirling engine in SolidWorks — modelling each component to precise dimensions with formal GD&T tolerances, producing a complete assembly drawing package (SE-001 through SE-003), and machining multiple parts on a lathe, CNC, and milling machine.

Timeline

Sep 2025

Drawing Package

SE-001 Assembled View · SE-002 Exploded View · SE-003 BOM

Tolerances

X.X ±0.1 · X.XX ±0.01 · X.XXX ±0.003 · Angles ±0.5°

Software

SolidWorks · Scale 2:3 Assembly / 1:4 Exploded

The Project

Full CAD Recreation of a Thermodynamic Engine

The Stirling engine was selected because it contains a wide variety of mechanical sub-systems — pistons, displacers, crankshafts, connecting rods, flywheel, bearings, and a burner assembly — requiring a different modelling approach for each and tight dimensional control across all mating interfaces.

Each of the 39 items in the BOM was modelled individually before being brought into an assembly, forcing attention to fit, clearance, and interference conditions across the full mechanism. The work was then documented to formal engineering drawing standards with a title block, tolerance stack, and drawing number series.

Machining

Shop Floor Execution

Multiple components were physically machined — not just modelled — putting the CAD work into real production context:

Lathe: Turned cylindrical features (shafts, pistons, cylinders) to precise diameters with surface finish control and tight roundness requirements
CNC: Introduction to Tool pathing and propper CNC use for 2D profiles, pockets, and drilled patterns
Milling machine: Faced stock, learned terminology, and produced flat reference surfaces to drawing dimension

Drawing SE-001 · Assembled View

Complete Assembly

Stirling Engine assembled view drawing SE-001 by D.Halvorssen

SE-001 · Assembled view · Scale 2:3 · Drawn by D.Halvorssen · 9/26/25

What This Demonstrates

Professsional Skills

Formal drawing standards: Producing a 3-sheet drawing package with title block, revision, drawing numbers (SE-001/002/003), and explicit tolerance callouts is what is expected in aerospace and product development.

DFM awareness: Machining parts after modelling them closes the loop — learning quickly where CAD assumptions fail in contact with real toolpaths and material behavior.

Multi-machine proficiency: Lathe, CNC, and mill are the core triad of a precision machine shop — grasping how each works allows me to improve my designs and make them feasible.

Drawing SE-003 · Bill of Materials

39-Item Component List

Item	Part Name	Qty	Item	Part Name	Qty
1	Base Plate	1	21	Flywheel Shaft	1
2	Bearing Block	1	22	Connector Link Pin	1
3	Base Plate Socket Head Cap Screw	2	23	Flywheel Set Screw	1
4	Base Plate Socket Countersunk Head Screw	2	24	Bearing Block Shaft	1
5	Bearing Block Bearing	2	25	Crank Web	1
6	Burner Bottle	1	26	Crank Web Set Screw	1
7	Burner Cap	1	27	Crank Web Shaft	1
8	O Ring	1	28	Gudgeon Block	1
9	Connector Link	1	29	Gudgeon Block Pin	1
10	Cylinder Plate	1	30	Gudgeon Block Screw	1
11	Displacer Cylinder	1	31	O Ring Power Cylinder	1
12	Displacer Cylinder Screw	4	32	Power Connector	1
13	O Ring Displacer Cylinder	1	33	Power Cylinder	1
14	Displacer Piston	1	34	Power Cylinder Screw	2
15	Displacer Piston Cap	1	35	Power Piston	1
16	Displacer Rod	1	36	Transfer Guide	1
17	Dowel Pin	2	37	Transfer Guide Bearing	1
18	Flywheel	1	38	Wick	1
19	E Clip	1	39	Air Chamber Plug NPT Fitting	1
20	Connector Link Bearing	1

Results & Takeaways

What I Learned

Modelling a complete mechanism teaches you to think in assemblies from the start. Every geometric decision on Part 1 affects how Part 22 fits, and cascading errors are expensive to fix late. The drawing package formalized this — writing tolerances forces you to decide exactly what matters dimensionally and what doesn’t.

Time on the machines built respect for tolerances that CAD makes look easy. A 0.003” fit demands real attention to setup, tool selection, and cutting parameters.

Relevant To

Any role requiring engineered-to-drawing mechanical components — aerospace structures, turbomachinery, or precision instrumentation — directly benefits from the CAD to shop floor experience and formal drawing discipline this project developed.

The formal drawing package (title block, revision, tolerance callouts, numbered BOM) matches industry documentation standards expected in any engineering environment.

StirlingEngineDesign