Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

608 Ball Chain Idler with matching Pulley Hack

by wulfdesign Feb 23, 2011
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Printed to my tantillus! Love it!

Sorry, but i don't think this is going to work, as i have spent a lot of time using ball chain as a drive mechanism for my machine "Makerap" http://www.thingiverse.com/thing:4142http://www.thingiverse.com/thi... . With the slightest resistance in movement the ball chain will loose steps.

Great design though:)

by Webca

also thought about using a cylinder rather than a sphere in the difference union on the pulley to get a deeper and less slip resistant grove for the ball chain to go into....

btw, your machine was one of the ones I looked at for inspiration on the design but went with the parametric OpenScad cause it was easier to change the design than going with some one elses design or my own having to rebuild it in Rhino every time I needed to change a parameter.

looks like the ball chain mechanism on the window blinds uses thinker twine.... I wonder how long mine will last once it gets built... also his uses a standard gear mechanism which is sleeved so the ball and chain has to go through it and cannot slip past... looks like that could cause a lot of wear after a lot of use. I think my design is better but I guess I could add a sleeve to it to keep it aligned and keep if from slipping if it was too loose.

Would it help any to just thread two ball chains next to eachother?

it may, I have this printed and ready to test. I have the steppers now but need to get/make connectors for my controllers and wire it up. hopefully in a day or two. if there is slippage your idea could provide a fairly easy solution.

thanks for your input...

yea, I was looking at all the other designs on this and found the ball depth didn't have enough bite.
unlike with the ones I printed up.
(side note: they took 3 days of printing, testing, reprinting to get them perfect for the first time).
I've seen blinds use a ball chains and they don't seem sli
p... so they must do something different.. I think a friend has one over at his house so I can take a look at his blinds this Sunday to see if what I've done is similar.

I'm hopeful and fairly confident.
one could also increase the depth so it doesn't have ANY choice but to follow the path... I th
ink what I've printed is a good compromise because making it that slip resistant may stall the stepper, break the chain, or break your extruder if something jams... think i'll take some slippage on the pulley over that. only testing will tell for sure. I've got my steppers on order so will find our
soon for sure.

Checking the blinds might be the answer:)

My pullies had a normal size of the diameter, but i think making them as big as possible will give the necessary grip needed.

I had a lot of problems with the ball chain breaking, but i used 3.5 mm ball chain, so any increase in size will take care of that;)

If you manage to get this foolproof i
t will be a great breakthrough in cheap drive-mechanism:)
Keep up the good work;)