Should I add a second rod?

I’ve made a double size plotter using bits from an MakeBlock plotter contrololled by an Arduino + other stuff I’ve bought. I near to switching it on but I have a question which someone here might be able to answer (or send me to a forum which could answer it).

The x-axis has two belts. One connected direct to the motor and one connected via a rod. Should I add a second rod at the far end to keep the motion smooth/correct/something? I’m worried that since the rod is long it may twist causing the “other” belt to drag.

(I’ve just noticed that the rod seems bent. I stood on a chair to take the photo, I’d better check it really isn’t bent!)

I can’t see any advantage in a second shaft connecting the drive belts at the other end of the frame. Toothed belts don’t stretch and if they are installed correctly I would not expect any variation between the ends.

There seems to be a lot of slack in the belts in your photo. There should be as little slack as possible to avoid backlash.

…R

Robin2:
I can't see any advantage in a second shaft connecting the drive belts at the other end of the frame. Toothed belts don't stretch and if they are installed correctly I would not expect any variation between the ends.

There seems to be a lot of slack in the belts in your photo. There should be as little slack as possible to avoid backlash.

...R

Thanks for the reply.

I thought that maybe with two rods the tendency to twist would be halved. I'll try your suggestion of just one rod and see how it goes.

Yes, the belts are slack because I have not yet tightened them up properly. I also need to straighten the one rod that is there.

giovanniguerra:
I thought that maybe with two rods the tendency to twist would be halved.

What tendency to twist?

Have you detected any?

If it ain't broke don't fix it :slight_smile:

...R

Nice looking project. If you think the single rod will cause a problem, put a bushing in the middle to hold it in position. You have lots of room for that!

Paul