Bills of materials
The parts lists per C beam
Some parts from your leadscrew (i.e. a bearing, the motor couplers, and an 8mm shim) can be reused.
Some extra parts – namely 6mm and 1mm spacer plates – are provided for free.
The ballscrew bearing is attached to the ballscrew with machined ends, and thus included in the ballscrew’s price.
Covid-19 and some history of trial and error with leadscrews, led to ball screws
Compared to leadscrews, ballscrews are quite simply the best thing since sliced bread.
Over the past 2 years, we tried out leadscrews in all shapes an forms.
First the 8mm Openbuilds leadscrews. They were fragile, and often got bent during transport, installation, or even packing. And at 1500mm they whip when rotation speeds are set high. They were not cheap either. And the supplier was far away, creating supply chain problems during the first Covid-19 wave in March and April 2020.
Then, we moved to a supplier nearby of standardized trapezoidal TR10 leadscrews. They were somewhat less fragile than the 8mm Openbuilds ones, yet, customers still regularly reported bends. Whip also still exists. Plus, the TR10x2 had a very low pitch, resulting in slow homing movements, much to the frustration of some customers who need machine for production purposes rather than private or hobby use.
So now we are moving towards these options:
- TR12 as standard (TR12x3) as have a better pitch than the TR10x2’s and as the 12mm makes them less subject to bending. These don’t have machined ends, so the standard holes in the workbee plates need to be enlarged slightly to 12-13mm opening. We provide 12mm bearings that fit the workbee plates, but there is a little downside: they do not have a plastic or metal dust cover, so they may need to be replaced over the lifespan of your machine when dust clogs up.
- 1204 ballscrews as upgrade. These have yet better pitch than the TR12’s and have machined ends so the standard bearings can be used (with dust covers) and they have precision M10x1 thread to put them under tension with a thrust bearing
This tutorial describes the installation of ballscrews, after removing the leadscrews.
1. Attach the bearing holder to the custom aluminium bearing nut
Important: NEVER remove the ballscrew bearing from the screw! There are tiny little metal balls that will fall out and that are impossible to put correctly in again – it will require to buy and ship a new ballscrew bearing
Use M4x14mm screws to squeeze the ballscrew bearing on the ballscrew bearing holder
2. Prepare the Y plates
Simply attach the ballscrew bearing holder to the Y plates, but this only needs to be done at 1 side (in contrast to the leadscrew nut blocks that needed 2):
The Y plates then need 7mm extra space, in order to accommodate the bigger diameter of the ballscrews (bearings) compared to the leadscrews (nuts) + to leave some space to let them move freely:
Add between each linear bearings and the Y plate a 6mm spacer plate and a 1mm spacer plate:
And then bolt the Y plate again to the linear bearings (that now have 7mm extra space)
3. Attach the ballscrew to the end plates (Y axis)
Then at the other side:
Before the Y end plate:
Take a 10mm collar with the two precision hex screws:
4. Prepare the X plate
Simply attach the ballscrew bearing holder to the X plate, but this only needs to be done at 1 side (in contrast to the leadscrew nut blocks that needed 2):
You can still use the spacer that you used before:
The X plate then needs 7mm extra space, in order to accommodate the bigger diameter of the ballscrews (bearings) compared to the leadscrews (nuts) + to leave some space to let them move freely:
Add between each linear bearings and the X plate a 6mm spacer plate and a 1mm spacer plate:
5. Attach the ballscrew between the Y axis plates (X axis)
At the 8mm side, proceed exactly as you did before for the 2 Y axis ball screws
For the 10mm side: also proceed exactly as you did before for the 2 Y axis ball screws