It would depend on the Number of Teeth In your case (60 T @ 6° = 360°)  and the 'Outer Circle' diameter. You need to find the center to 'Move' the one pitch you have and 'Create a circular pattern'

An image would be good.

Is the belt you want on this site?  https://www.mcmaster.com/timing-belts

If it is, Select the Type , Size, Number of teeth. Then select the 'Product number' - 'Product Detail' - Download as a 'Step' file.

Image of single pitch

Intention is to be able to model the whole belt

Drive end will be 20T nominal outside 12mm diam

Shaft end will be 60T nominal outside 40mm diam

Drive to Shaft separation TBD

Was trying to draw up components so that I could

• select belt size
• allow for belt tensioning

Not sure I follow

• You need to find the center to 'Move' the one pitch you have and 'Create a circular pattern'

The one pitch needs to be 'deformed' to match the 6 degrees of arc else the next one pitch won't butt up to it (form a solid)

Found what you were referring to

https://designspark.zendesk.com/hc/en-us/articles/212638685-How-do-I-create-a-rotational-pattern-

getting close

Thanks

I am assuming it is similar to creating a 'Spur Gear'. The 'Pitch or Module' must be the same in both gears otherwise they would not 'mesh' together. Is it not the same that the belt would have to mesh with both wheels and the belt?

You can not have the 60 teeth on one wheel and 20 on the other unless they have the same 'Module/Pitch', which would be the same as the Pitch for the belt.

You need to draw this 'Pitch' shape on the 'Pitch Diameter' using lines drawn from the center to the outside edge, this will create it's own curve. Once you have the shape of one 'Pitch' you need to rotate it around the 'Pitch Diameter' using the center of it as the axis point. Use the 'Move' tool with the 'Create Patterns' option.

The 'Gears' in the image have the same 'Module/Pitch' so will mesh together.

Yes the 20T 'gear' is same 'Module/Pitch' so should be ok

And both 'gears' are described as GT2 types - so should be compatible with belt

Now that I've got a pattern - can't seem to pull it to make a 3D shape ??

Have you got a 'Surface' or just 'Curves'?

If no Surface then Select all of the 'Curves' and use the 'Fill' tool to create a surface. If that does not work then make sure that there are no gaps in the drawing. Zoom in to where one 'pitch' joins the next to check.

I've got a pattern with 60 component|surface s as below

no gaps as far as I can tell - have zoomed in to check

When you created the pattern you selected the Component.

Select the Solid or Surface within the Component to use as a pattern.

I would select one Surface and Copy/Move it with the center as the axis 6°. So there are two Surfaces. Trim the curves where they overlap. Now Move create pattern with 30 count. Trim overlaps. Then try to Pull.

You could try to select all of the Surfaces by dragging a box around them and use the 'Combine' tool. It may not work as each Surface is in a Component.

It may seem obvious but have you selected one surface and 'Pulled' that?