steve/timing-belt

GT2 (2GT) open timing belt as a straight envelope: width and length as parameters, with common lengths as presets.

v1.1.0 Latest STEVE MIT 0

Open in STEVE

Isometric

Parameters

Preset15 sizes

Width4–15 mm

Length10–5000 mm

Detail

fullsimple

full: teeth. simple: a plain bar of the overall height, for big assemblies.

Defaults built

part.py 37 lines · Python · STEVE runtime · checked

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"""Open-ended GT2 (2GT) timing belt, straight, 2 mm pitch: length along X, centred on the origin, back of the belt up, teeth down on the XY plane. detail = "full": the teeth along the

length; tooth width is a proportion for looks, not for design (only the height and pitch are published). A belt over 500 mm carries teeth along 250 mm at each end, the middle at full

height: more teeth build too slowly for a belt. detail = "simple": a plain bar of the belt's overall height."""

import math

from steve import Model

width = 6 # mm Belt width

length = 300 # mm Belt length

detail = "full" # full: teeth; simple: a plain bar

# Handson Technology, GT2 belt data sheet: 2 mm pitch, belt height 1.38 mm, tooth height 0.75 mm.

HEIGHT = 1.38

TOOTH_HEIGHT = 0.75

PITCH = 2.0

TOOTH_WIDTH = 1.2 # a proportion for looks

TOOTHED_LENGTH = 500 # mm: the most of a belt that carries drawn teeth

model = Model()

if detail == "simple":

outline = [(-length / 2, 0), (length / 2, 0), (length / 2, HEIGHT), (-length / 2, HEIGHT)]

else:

back = TOOTH_HEIGHT

outline = [(-length / 2, back), (-length / 2, HEIGHT), (length / 2, HEIGHT), (length / 2, back)]

count = int(length // PITCH)

centres = [(i - (count - 1) / 2) * PITCH for i in range(count)]

if length > TOOTHED_LENGTH: # teeth at both ends, so an end view shows them

kept = int(TOOTHED_LENGTH / 2 // PITCH)

centres = centres[:kept] + centres[-kept:]

for x in reversed(centres):

half = TOOTH_WIDTH / 2

outline += [(x + half, back), (x + half * 0.6, 0.0), (x - half * 0.6, 0.0), (x - half, back)]

with model.sketch("belt_sketch", on="XZ", name="Belt section") as sk:

sk.polyline("outline", outline, closed=True)

model.extrude("belt", "belt_sketch", distance=width, both=True, name="Belt")

result = model.result()

"""Open-ended GT2 (2GT) timing belt, straight, 2 mm pitch: length along X, centred on the origin, back of the belt up, teeth down on the XY plane. detail = "full": the teeth along the
length; tooth width is a proportion for looks, not for design (only the height and pitch are published). A belt over 500 mm carries teeth along 250 mm at each end, the middle at full
height: more teeth build too slowly for a belt. detail = "simple": a plain bar of the belt's overall height."""
import math

from steve import Model

width = 6  # mm Belt width
length = 300  # mm Belt length
detail = "full"  # full: teeth; simple: a plain bar

# Handson Technology, GT2 belt data sheet: 2 mm pitch, belt height 1.38 mm, tooth height 0.75 mm.
HEIGHT = 1.38
TOOTH_HEIGHT = 0.75
PITCH = 2.0
TOOTH_WIDTH = 1.2  # a proportion for looks
TOOTHED_LENGTH = 500  # mm: the most of a belt that carries drawn teeth

model = Model()
if detail == "simple":
    outline = [(-length / 2, 0), (length / 2, 0), (length / 2, HEIGHT), (-length / 2, HEIGHT)]
else:
    back = TOOTH_HEIGHT
    outline = [(-length / 2, back), (-length / 2, HEIGHT), (length / 2, HEIGHT), (length / 2, back)]
    count = int(length // PITCH)
    centres = [(i - (count - 1) / 2) * PITCH for i in range(count)]
    if length > TOOTHED_LENGTH:   # teeth at both ends, so an end view shows them
        kept = int(TOOTHED_LENGTH / 2 // PITCH)
        centres = centres[:kept] + centres[-kept:]
    for x in reversed(centres):
        half = TOOTH_WIDTH / 2
        outline += [(x + half, back), (x + half * 0.6, 0.0), (x - half * 0.6, 0.0), (x - half, back)]
with model.sketch("belt_sketch", on="XZ", name="Belt section") as sk:
    sk.polyline("outline", outline, closed=True)
model.extrude("belt", "belt_sketch", distance=width, both=True, name="Belt")
result = model.result()

pypart.toml 137 lines · TOML

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name = "steve/timing-belt"

version = "1.1.0"

runtime = "steve"

license = "MIT"

summary = "GT2 (2GT) open timing belt as a straight envelope: width and length as parameters, with common lengths as presets."

description = """Open-ended GT2 timing belt, 2 mm pitch, straight, with its teeth. A belt over 500 mm carries teeth along 250 mm at each end. detail = simple is a plain bar of the overall height for big assemblies. Length along X, centred on the origin. See the README; not affiliated with any belt brand."""

tags = ["belt", "timing-belt", "gt2", "2gt", "power-transmission"]

changes = "Real teeth. detail = simple keeps a plain bar."

[parameters.width]

type = "number"

default = 6

min = 4

max = 15

unit = "mm"

label = "Width"

[parameters.length]

type = "number"

default = 300

min = 10

max = 5000

unit = "mm"

label = "Length"

[parameters.detail]

type = "choice"

default = "full"

choices = ["full", "simple"]

label = "Detail"

description = "full: teeth. simple: a plain bar of the overall height, for big assemblies."

[[presets]]

id = "GT2-W6-L50"

title = "GT2 belt, 6 mm wide, 50 mm"

params = { width = 6, length = 50 }

aliases = ["GT2 belt 50", "GT2 timing belt 50mm", "GT2 belt", "2GT belt", "2GT 6mm 50", "GT2", "belt profile=GT2; straight reference length=50 mm; simplified envelope"]

standard = "Handson GT2"

[[presets]]

id = "GT2-W6-L100"

title = "GT2 belt, 6 mm wide, 100 mm"

params = { width = 6, length = 100 }

aliases = ["GT2 belt 100", "GT2 timing belt 100mm", "GT2 belt", "2GT belt", "2GT 6mm 100", "GT2", "belt profile=GT2; straight reference length=100 mm; simplified envelope"]

standard = "Handson GT2"

[[presets]]

id = "GT2-W6-L150"

title = "GT2 belt, 6 mm wide, 150 mm"

params = { width = 6, length = 150 }

aliases = ["GT2 belt 150", "GT2 timing belt 150mm", "GT2 belt", "2GT belt", "2GT 6mm 150", "GT2", "belt profile=GT2; straight reference length=150 mm; simplified envelope"]

standard = "Handson GT2"

[[presets]]

id = "GT2-W6-L200"

title = "GT2 belt, 6 mm wide, 200 mm"

params = { width = 6, length = 200 }

aliases = ["GT2 belt 200", "GT2 timing belt 200mm", "GT2 belt", "2GT belt", "2GT 6mm 200", "GT2", "belt profile=GT2; straight reference length=200 mm; simplified envelope"]

standard = "Handson GT2"

[[presets]]

id = "GT2-W6-L250"

title = "GT2 belt, 6 mm wide, 250 mm"

params = { width = 6, length = 250 }

aliases = ["GT2 belt 250", "GT2 timing belt 250mm", "GT2 belt", "2GT belt", "2GT 6mm 250", "GT2", "belt profile=GT2; straight reference length=250 mm; simplified envelope"]

standard = "Handson GT2"

[[presets]]

id = "GT2-W6-L300"

title = "GT2 belt, 6 mm wide, 300 mm"

params = { width = 6, length = 300 }

aliases = ["GT2 belt 300", "GT2 timing belt 300mm", "GT2 belt", "2GT belt", "2GT 6mm 300", "GT2", "belt profile=GT2; straight reference length=300 mm; simplified envelope"]

standard = "Handson GT2"

[[presets]]

id = "GT2-W6-L400"

title = "GT2 belt, 6 mm wide, 400 mm"

params = { width = 6, length = 400 }

aliases = ["GT2 belt 400", "GT2 timing belt 400mm", "GT2 belt", "2GT belt", "2GT 6mm 400", "GT2", "belt profile=GT2; straight reference length=400 mm; simplified envelope"]

standard = "Handson GT2"

[[presets]]

id = "GT2-W6-L500"

title = "GT2 belt, 6 mm wide, 500 mm"

params = { width = 6, length = 500 }

aliases = ["GT2 belt 500", "GT2 timing belt 500mm", "GT2 belt", "2GT belt", "2GT 6mm 500", "GT2", "belt profile=GT2; straight reference length=500 mm; simplified envelope"]

standard = "Handson GT2"

[[presets]]

id = "GT2-W6-L600"

title = "GT2 belt, 6 mm wide, 600 mm"

params = { width = 6, length = 600 }

aliases = ["GT2 belt 600", "GT2 timing belt 600mm", "GT2 belt", "2GT belt", "2GT 6mm 600", "GT2", "belt profile=GT2; straight reference length=600 mm; simplified envelope"]

standard = "Handson GT2"

[[presets]]

id = "GT2-W6-L750"

title = "GT2 belt, 6 mm wide, 750 mm"

params = { width = 6, length = 750 }

100

aliases = ["GT2 belt 750", "GT2 timing belt 750mm", "GT2 belt", "2GT belt", "2GT 6mm 750", "GT2", "belt profile=GT2; straight reference length=750 mm; simplified envelope"]

101

standard = "Handson GT2"

102

103

[[presets]]

104

id = "GT2-W6-L1000"

105

title = "GT2 belt, 6 mm wide, 1000 mm"

106

params = { width = 6, length = 1000 }

107

aliases = ["GT2 belt 1000", "GT2 timing belt 1000mm", "GT2 belt", "2GT belt", "2GT 6mm 1000", "GT2", "belt profile=GT2; straight reference length=1000 mm; simplified envelope"]

108

standard = "Handson GT2"

109

110

[[presets]]

111

id = "GT2-W9-L300"

112

title = "GT2 belt, 9 mm wide, 300 mm"

113

params = { width = 9, length = 300 }

114

aliases = ["GT2 9mm belt 300", "GT2 9mm belt"]

115

standard = "Handson GT2"

116

117

[[presets]]

118

id = "GT2-W9-L500"

119

title = "GT2 belt, 9 mm wide, 500 mm"

120

params = { width = 9, length = 500 }

121

aliases = ["GT2 9mm belt 500", "GT2 9mm belt"]

122

standard = "Handson GT2"

123

124

[[presets]]

125

id = "GT2-W9-L1000"

126

title = "GT2 belt, 9 mm wide, 1000 mm"

127

params = { width = 9, length = 1000 }

128

aliases = ["GT2 9mm belt 1000", "GT2 9mm belt"]

129

standard = "Handson GT2"

130

131

[[presets]]

132

id = "GT2-W6-L300-simple"

133

title = "GT2 belt, 6 mm wide, 300 mm, simple (no teeth)"

134

params = { width = 6, length = 300, detail = "simple" }

135

aliases = ["GT2 belt simple"]

136

standard = "Handson GT2"

137

name = "steve/timing-belt"
version = "1.1.0"
runtime = "steve"
license = "MIT"
summary = "GT2 (2GT) open timing belt as a straight envelope: width and length as parameters, with common lengths as presets."
description = """Open-ended GT2 timing belt, 2 mm pitch, straight, with its teeth. A belt over 500 mm carries teeth along 250 mm at each end. detail = simple is a plain bar of the overall height for big assemblies. Length along X, centred on the origin. See the README; not affiliated with any belt brand."""
tags = ["belt", "timing-belt", "gt2", "2gt", "power-transmission"]
changes = "Real teeth. detail = simple keeps a plain bar."

[parameters.width]
type = "number"
default = 6
min = 4
max = 15
unit = "mm"
label = "Width"

[parameters.length]
type = "number"
default = 300
min = 10
max = 5000
unit = "mm"
label = "Length"

[parameters.detail]
type = "choice"
default = "full"
choices = ["full", "simple"]
label = "Detail"
description = "full: teeth. simple: a plain bar of the overall height, for big assemblies."

[[presets]]
id = "GT2-W6-L50"
title = "GT2 belt, 6 mm wide, 50 mm"
params = { width = 6, length = 50 }
aliases = ["GT2 belt 50", "GT2 timing belt 50mm", "GT2 belt", "2GT belt", "2GT 6mm 50", "GT2", "belt profile=GT2; straight reference length=50 mm; simplified envelope"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W6-L100"
title = "GT2 belt, 6 mm wide, 100 mm"
params = { width = 6, length = 100 }
aliases = ["GT2 belt 100", "GT2 timing belt 100mm", "GT2 belt", "2GT belt", "2GT 6mm 100", "GT2", "belt profile=GT2; straight reference length=100 mm; simplified envelope"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W6-L150"
title = "GT2 belt, 6 mm wide, 150 mm"
params = { width = 6, length = 150 }
aliases = ["GT2 belt 150", "GT2 timing belt 150mm", "GT2 belt", "2GT belt", "2GT 6mm 150", "GT2", "belt profile=GT2; straight reference length=150 mm; simplified envelope"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W6-L200"
title = "GT2 belt, 6 mm wide, 200 mm"
params = { width = 6, length = 200 }
aliases = ["GT2 belt 200", "GT2 timing belt 200mm", "GT2 belt", "2GT belt", "2GT 6mm 200", "GT2", "belt profile=GT2; straight reference length=200 mm; simplified envelope"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W6-L250"
title = "GT2 belt, 6 mm wide, 250 mm"
params = { width = 6, length = 250 }
aliases = ["GT2 belt 250", "GT2 timing belt 250mm", "GT2 belt", "2GT belt", "2GT 6mm 250", "GT2", "belt profile=GT2; straight reference length=250 mm; simplified envelope"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W6-L300"
title = "GT2 belt, 6 mm wide, 300 mm"
params = { width = 6, length = 300 }
aliases = ["GT2 belt 300", "GT2 timing belt 300mm", "GT2 belt", "2GT belt", "2GT 6mm 300", "GT2", "belt profile=GT2; straight reference length=300 mm; simplified envelope"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W6-L400"
title = "GT2 belt, 6 mm wide, 400 mm"
params = { width = 6, length = 400 }
aliases = ["GT2 belt 400", "GT2 timing belt 400mm", "GT2 belt", "2GT belt", "2GT 6mm 400", "GT2", "belt profile=GT2; straight reference length=400 mm; simplified envelope"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W6-L500"
title = "GT2 belt, 6 mm wide, 500 mm"
params = { width = 6, length = 500 }
aliases = ["GT2 belt 500", "GT2 timing belt 500mm", "GT2 belt", "2GT belt", "2GT 6mm 500", "GT2", "belt profile=GT2; straight reference length=500 mm; simplified envelope"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W6-L600"
title = "GT2 belt, 6 mm wide, 600 mm"
params = { width = 6, length = 600 }
aliases = ["GT2 belt 600", "GT2 timing belt 600mm", "GT2 belt", "2GT belt", "2GT 6mm 600", "GT2", "belt profile=GT2; straight reference length=600 mm; simplified envelope"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W6-L750"
title = "GT2 belt, 6 mm wide, 750 mm"
params = { width = 6, length = 750 }
aliases = ["GT2 belt 750", "GT2 timing belt 750mm", "GT2 belt", "2GT belt", "2GT 6mm 750", "GT2", "belt profile=GT2; straight reference length=750 mm; simplified envelope"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W6-L1000"
title = "GT2 belt, 6 mm wide, 1000 mm"
params = { width = 6, length = 1000 }
aliases = ["GT2 belt 1000", "GT2 timing belt 1000mm", "GT2 belt", "2GT belt", "2GT 6mm 1000", "GT2", "belt profile=GT2; straight reference length=1000 mm; simplified envelope"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W9-L300"
title = "GT2 belt, 9 mm wide, 300 mm"
params = { width = 9, length = 300 }
aliases = ["GT2 9mm belt 300", "GT2 9mm belt"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W9-L500"
title = "GT2 belt, 9 mm wide, 500 mm"
params = { width = 9, length = 500 }
aliases = ["GT2 9mm belt 500", "GT2 9mm belt"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W9-L1000"
title = "GT2 belt, 9 mm wide, 1000 mm"
params = { width = 9, length = 1000 }
aliases = ["GT2 9mm belt 1000", "GT2 9mm belt"]
standard = "Handson GT2"

[[presets]]
id = "GT2-W6-L300-simple"
title = "GT2 belt, 6 mm wide, 300 mm, simple (no teeth)"
params = { width = 6, length = 300, detail = "simple" }
aliases = ["GT2 belt simple"]
standard = "Handson GT2"

README.md 13 lines · Markdown

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Timing belt (GT2)

Open-ended GT2 (2GT) belt, 2 mm pitch, straight. Length along X, centred on the origin, teeth down on the XY plane. Tooth pitch and height are published; the tooth's width and taper are proportions for looks, not for design. A belt over 500 mm carries teeth along 250 mm at each end, because more take too long to build. detail = "simple" is a plain bar.

Source

Handson Technology, GT2 belt data specs: pitch 2 mm, belt height 1.38 mm, tooth height 0.75 mm, as hosted at https://naylampmechatronics.com/img/cms/000117/000117 gt2-belt-B.pdf. MISUMI's catalogue gives the same 0.75 mm tooth height for 2GT (https://uk.misumi-ec.com/pdf/fa/2014/P1_1381-1382_F19_EN_001.pdf).

Some sellers list a 1.52 mm belt height for GT2 belts. Width and length are the belt's designation. Preset lengths: step.parts catalogue metadata (MIT, library/NOTICE.md). GT3, HTD3M and HTD5M belts aren't offered yet: no table read gives their overall height.

# Timing belt (GT2)

Open-ended GT2 (2GT) belt, 2 mm pitch, straight. Length along X, centred on the origin, teeth down on the XY plane. Tooth pitch and height are published; the tooth's width and taper are proportions for looks, not for design. A belt over 500 mm carries teeth along 250 mm at each end, because more take too long to build. `detail = "simple"` is a plain bar.

## Source

Handson Technology, *GT2 belt* data specs: pitch 2 mm, belt height 1.38 mm, tooth height 0.75 mm, as hosted at
<https://naylampmechatronics.com/img/cms/000117/000117%20gt2-belt-B.pdf>. MISUMI's catalogue gives the same 0.75 mm tooth height for 2GT
(<https://uk.misumi-ec.com/pdf/fa/2014/P1_1381-1382_F19_EN_001.pdf>).

Some sellers list a 1.52 mm belt height for GT2 belts. Width and length are the belt's designation. Preset lengths: step.parts catalogue
metadata (MIT, `library/NOTICE.md`). GT3, HTD3M and HTD5M belts aren't offered yet: no table read gives their overall height.

Use this part

STEVE

Open in STEVE

Open it in STEVE The STEVE runtime runs in STEVE: open the part there, or download the code and bundle.

Get the code

curl -o part.py "https://pythonparts.org/p/steve/timing-belt/v/1.1.0/raw/part.py"

Raw files, bundle and API

part.py
pypart.toml
README.md
bundle.tar.gzthe package, as published

curl "https://pythonparts.org/api/v1/parts/steve/timing-belt/1.1.0"

The version's JSON (parameters, presets, files); add /build?name=value for a build at other values.

About this part

steve72 parts

Profile

License: MIT

Permissive: use, change and sell it; keep the copyright notice.

Runtime: STEVE
Requirements: None stated in the code
Built with: CadQuery 2.9.0.dev0
Published: Nov 5, 2026
Downloads: 0
Builds: 0
Stars: 0
Bundle: 0b91f060ee35…

#belt #timing-belt #gt2 #2gt #power-transmission

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Open-ended GT2 timing belt, 2 mm pitch, straight, with its teeth. A belt over 500 mm carries teeth along 250 mm at each end. detail = simple is a plain bar of the overall height for big assemblies. Length along X, centred on the origin. See the README; not affiliated with any belt brand.

Timing belt (GT2)

Source

1.1.0 Latest Nov 5, 2026 · 1 hour ago Compare with 1.0.0

Real teeth. detail = simple keeps a plain bar.
1.0.0 Nov 4, 2026 · 3 hours ago

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