Any ideas for lightweight chainlink?

I'm building a project where two stepper motors control the exact position of a pointer (over a map). I need the pointer to be hanging from the two stepper motors, with the extra chain (or string, if that'd be better) hanging down the other side, so the entire contraption will look like a big 'M' (where the tops are the motors and the middle is the pointer)

Because I need to control exact positions I think the best plan will be to have the two stepper motors fitted with spur gears and use thin bike chain over them to move the pointer. Bike chain would be good, except that it's too thick (it'd obscure the map too much in my opinion) and might be too heavy (there'll be ~3m of the stuff on either side).

So, my question is: does anyone have any good ideas for reasonably lightweight chainlink (or some other non-slip linkage) and where I could by it (preferably here in the UK)?

lemonie6 years ago

What about fishing / strimmer - line?
Multiple wraps around a drum should do you.

Exactly what I was going to say. Multiple wraps would prevent slipping.
seandogue6 years ago
There are plastic timing/drive chains available for this purpose. Search MCmaster or similar parts sites.
frollard6 years ago
like this? done with string :)