View Full Version : Dilemma with ball screw and motor mounting

12-08-2011, 09:31 AM
Morning all

Now my ball screw has come I have found a problem and Iím sure Iím not the first

I would like to mount the ball screw to the under side of the supported rail for safety as I do have little fingers to worry about but if I have to mount to the side I will

The machined end that connects to the stepper motor is 15mm long after bearing mount is fixed, my aluminium is 45mm thick and then the stepper motor is fixed to itís mount requires a extra 15mm to join to the coupler. So to start with Iím 30mm to short.

So as you see I need a extra 75mm

Now I have made my cnc an extra 100mm longer so the cutting front edge is not wasted by the gantry over hang

Length of bed is 1200+ 90 for the aluminium profile
Supported rails and ball screw is 1100mm long

To make up the extra length I was thinking of adding a extra bearing support with a 10mm rod 155mm long and connecting it with a extra coupler

I hope this makes sense and hopping the image I have attached improves my chances of sorting this problem out.


James and Luke :eek::eek:

12-08-2011, 10:04 AM
How do you take the photos such that the scratches don't show up on the aluminium?
An extra shaft with a bearing would work, but it's a lot of hassle. You could have one rigid coupling and one flexible to save a few pennies...probably no need for the extra bearing, not sure.
Why not put the shaft extension on the other end and move the ballscrew towards the stepper motor?

The simple answer unfortunately is you should have bought a longer ballscrew!

12-08-2011, 10:23 AM
like you said should have bought a longer ball screw in the first place

can you make two rigid couplings for me Jonathan ??

ball screw shaft size is 10 to coupler 10mm I could send you a drawing if you like


ps I did buy a bigger ball screw to start with but I am getting greedy on my cnc size to start with I wanted only a cutting length of 900mm:whistling::whistling:

12-08-2011, 10:38 AM
can you make two rigid couplings for me Jonathan ??

I can do, here's some I made earlier:


So either like that, or I could make the coupling and bar one piece if you let me know exactly how long the bar needs to be.

12-08-2011, 10:58 AM
:yahoo:they are fine 10 mm holes please