ISO 53 Involute Spur Gears, GT2/HTD Timing Pulleys & NEMA Motor Mount Engineering Guide
Parametric Formulas & Dimensional Allowances
Two gears will only mesh properly if their Metric Module (m) is identical.
Computes the exact Pitch Diameter (input as L) for any synchronous belt pitch (e.g., P = 2.0mm for GT2, 3.0mm for HTD-3M, 5.0mm for HTD-5M).
Standard Material & Tooling Tolerance Table
| Standard Frame / Drive | Body / Pitch Spec | Pilot Boss Bore (W) | Bolt Hole Circle / Pitch (H) | Fastener Size | Primary Automation Application |
|---|---|---|---|---|---|
| NEMA 14 Stepper Motor | 35.2 × 35.2 mm | Ø 22.0 mm | 26.0 mm Square Pitch | 4 × M3 Screws | Compact direct-drive extruders, lightweight pan/tilt gimbals |
| NEMA 17 Stepper Motor | 42.3 × 42.3 mm | Ø 22.0 mm | 31.0 mm Square Pitch | 4 × M3 Screws | 3D printers, desktop diode lasers, camera sliders, robotics |
| NEMA 23 Stepper Motor | 56.4 × 56.4 mm | Ø 38.10 mm (1.50") | 47.14 mm (1.856") Pitch | 4 × M5 Screws | CNC routers, plasma tables, benchtop milling machines |
| NEMA 34 Stepper Motor | 86.0 × 86.0 mm | Ø 73.03 mm (2.875") | 69.58 mm (2.74") Pitch | 4 × M6 Bolts | Heavy industrial CNC gantries, automated lathes |
| GT2 Timing Pulley (2mm Pitch) | P = 2.00 mm | Ø 5.0 / 6.35 / 8.0 mm | 20T (D_p=12.73) / 40T (D_p=25.46) | M3 Set Screw / Key | Linear motion belt drives, CoreXY 3D printers |
| HTD 5M Timing Pulley (5mm Pitch) | P = 5.00 mm | Ø 12.0 – 20.0 mm Keyed | 24T (D_p=38.20) / 36T (D_p=57.30) | DIN 6885 Keyway | High-torque CNC axis reduction drives, e-mobility |
Generate Custom 1:1 .DXF, .SVG & .PDF Files Using This Standard
Involute Spur Gear CAD
Generate 1:1 metric module spur gears with custom Pitch Diameter, Tooth Count (Z), and Center Shaft Bore in .DXF, .SVG, and .PDF for laser cutting, CNC, and waterjet.
NEMA Stepper Motor Flange
Generate 1:1 NEMA 17, NEMA 23, and NEMA 34 stepper motor mounting faceplates and bearing flanges in .DXF, .SVG, and .PDF with exact pilot boss bores and bolt hole pitches.
Timing Belt Pulley & Sprocket
Generate 1:1 synchronous timing belt pulleys and sprockets in .DXF, .SVG, and .PDF with sinusoidal tooth gullets, DIN 6885 shaft keyway bore, and lightening holes.
Ready-to-Cut Product Presets (Mechanical CAD)
48.0 mm Pitch Circle Diameter (52.0 mm Outside Diameter), Z=24 Teeth, Module m=2.0 mm, α=20°
NEMA ICS 16 Standard NEMA 17 Motor Faceplate (42.3mm Motor Body on 56x56mm Plate)
36-Tooth Synchronous Pulley | Pitch Circle Ø72.0 mm | Circular Pitch 6.28 mm | 3.0–6.0 mm Face Width
NEMA ICS 16 Standard NEMA 23 Motor Faceplate (56.4mm Motor Body on 68×68mm Heavy Plate)
Standard NEMA 34 Frame (86 × 86 mm Motor Face) with Ø73.0 mm Registration Pilot Boss
40-Tooth Synchronous Belt Driven Sprocket (Ø80.0 mm Pitch Circle, 6.28 mm Circular Pitch)
Shop-Floor Troubleshooting & Engineering FAQs
Why is the center pilot bore on a NEMA 23 mount 38.1mm instead of a round metric number?
NEMA (National Electrical Manufacturers Association) standards originated in imperial inches: the NEMA 23 pilot boss is exactly 1.500 inches (38.10 mm) and the bolt hole spacing is 1.856 inches (47.14 mm), whereas NEMA 17 adopted metric 22.0 mm pilot and 31.0 mm bolt spacing.
What is the best plastic for laser-cutting custom gears and timing pulleys?
Delrin / Acetal homopolymer (POM) in 3mm to 6mm thickness is the gold standard for laser-cut gears and pulleys. Unlike acrylic (which is brittle under tooth impact), Delrin has high fatigue resistance, natural lubricity, and cuts cleanly on CO2 lasers.
How do I prevent a laser-cut gear or pulley from slipping on a smooth shaft?
Our Timing Pulley Generator automatically cuts a standard DIN 6885 rectangular shaft keyway into the central bore so a machine key locks rotational torque positively.
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