Shafts anchored in what?

GridBot
1

Hi there,

I’m gathering parts to build a GridBot 2. And I will sure have questions along the way when I assemble it.
In fact I already have a question.

How are the 400x8mm shafts anchored into the “z-plates”? Are they just stuck in the holes?

2

Hi @Stout. Looking forward to see your build as it progresses. Yes, the shafts are press-fit into the matching 8mm holes in the Z mounts. While they are tight and won’t move, the weight of the bed and gravity does the rest. This is more true with the Z lead screw. It is only anchored at the bottom. The shafts ensure perfect Z motion while the screw only acts as a pusher. Earlier designs had the screw constrained top and bottom, and this often led to an over-constrained setup that would bind.

3

Hi Stewart,
Thanks for the detailed explanation. Then I don’t bother to worry about that anymore.

I’m probably making the Z mounts in aluminium or 6mm routed acrylic glass.

Do you suggest I should start a new build thread here?

4

I’ve made the brackets out of laser-cut acrylic and 3D printed plastic, but never something a rigid as aluminum. I would be concerned that unless parts fit exactly, they won’t at all. A lot of the Z axis parts are press-fit, so having some give is important.

Please start a new thread with an appropriate title when you’re ready to start posting pics and other progress.

5

I will. I’m currently summing up the parts. Some are still in the post enviroment. I will do some slight modifications to the original GridBot.

How are the x & y timing belts secured?

In the BOM it says lead screw guide. Is it the bronze nut that you mean or is it a guide at the foot of the lead screw?

I saw that you added a direct drive test in the Experimental. Is it something you working on now or can I grab the step files and print it?

6

The X/Y belts are looped through the center block as shown in the CAD and secured to itself (teeth face each other when properly routed) with two small zip-ties at each end.

I built 3 experimental direct drive systems. All worked well. I haven’t blessed any of them yet. I even started a 2.5 build with a different gantry setup.

This works, but I want to improve cooling.

At the moment, I have four GridBots in four different drive configurations.

7

Thanks for quick response. :grinning:

I’ll print it out and give it a try. Are you using a pancake stepper?

8

Yep to reduce mass. The drive I chose has reduction gearing.