linkages query ...

hello … i have an 8 bar and it becomes loose after about a min …

i normally get a screw, and use a kelp and a washer …

what do people use ?

Instead of keps, use nylock nuts.

By ‘kelp’, did you mean to say a Keps Nut? Whenever our team builds a linkage, we typically use the screw-spacer-nut method for the joints, but we always use Nylock Nuts so that the joints can be loose enough to spin freely, but will not loosen further or fall apart easily.

~Jordan

yeh we use kelp nuts … ok i will try nylock

thanks everyone

I’ve done a quick CAD of what I find works best.

https://dl.dropbox.com/u/80165681/help/front.jpg
https://dl.dropbox.com/u/80165681/help/side.jpg

That uses a 0.125" white spacer between the bits of metal and Nylock nut. Remember not to tighten the Nylocks too much. You want as little friction as possible while still being tight enough to prevent arm wobble.

Hope this was helpful.

thats great … :smiley:

i will do this today and see the difference

cheers

Here’s a variation of how I use Keps nuts as a joint:

https://vexforum.com/gallery/files/4/1/6/3/0/8/joint.jpg

The head of the screw is tightened against the bottom Keps nut. The two Keps nuts on the top are tightened against each other. There is a miniscule gap between the Keps nut and the top delrin mount between the C-channels.

You can experiment with putting the delrin mounts in on the inside of the C-channels and a nylon spacer in between. The point is that you can use 3 Keps nuts in accordance to delrin mounts to make a viable joint.

You could probably forgo the bottom Keps nut in this diagram, too.

Another variation is to use 2 Keps nuts, tightening them on either side of the top C-channel, and leaving a miniscule gap for the bottom C-channel. that is how we made our 6-bar earlier this season.