index  >  Toothed Belts  |  Imperial sizes  |  Metric sizes

Toothed Belts

Imperial sizes

For animatronic work the sizes most likely to be used are MXL and XL.
These are still widely available although a shift to metric belts is occurring.
" is used to denote inches so 3" is 3 inches and 1/16" is one sixteenth of an inch.
MXL
The tooth pitch is 0.080" and the belts come in various lengths and widths.
The belt width will be in sixteenths of an inch.
Shown here are two sizes of pulley, one with two flanges and one with only one.
The pulleys normally have a width to take 1/4" belts.
Also shown are two MXL belts, both have a width of 3/16" and one has 64 teeth and the other 106 teeth.
Sometimes the sizes are printed on the belt.
A common material is polyurethane with polyester threads in them for strength.

XL
XL is the next size up.
The tooth pitch is 0.2" and the belts come in various lengths and widths.
Shown here are two sizes of pulley, one with no flanges and one with one.
The pulleys normally have a width to take 3/8" belts.
The belt size is normally printed on the belt.
Shown are two XL belts,-
one printed 100XL031 has a length of 10" (ie 50 teeth) and a width of 0.31",
the other printed 70XL031 has a length of 7" (ie 35 teeth) and a width of 0.31",
A common material is rubber with polyester threads in them for strength.


Metric sizes

There are a number of different metric tooth forms and pitches, don't get them mixed up.
T2 and T5 belts have (always?) steel cores in them for strength, they are very strong but are far too stiff for ordinary animatronics work.
Nearly the same pitxh as MXL is 2GT, don't get them mixed up.
2GT tooth pitch is 2mm (millimetres), the width normally 6mm, and again they come in various lengths and widths.
The material will be rubber with poyester cores for strength.
2GT is becomming widely available because it is used on a lot of hobby 3D printers.
On the left is 2GT belt (black) and pulley and on the right an MXL belt (orange) and pulley.
You can see the teeth on the two belts do not match up.