Are taper lock pulleys a good choice for ball screws?

[routercnc]

The other thing to think about is for an axis with double ballscrews you need to be able to square the gantry. This might mean being able to rotate one ballscrew very slightly by hand (without the pulley secured) until the gantry is square, so a key way or D flat would not work as this puts the pulley at a fixed location on the ballscrew. A simple pair of grub screws allows the pulley to sit at any angle on the ballscrew.

Also on the inertia side I did the calculations for machine design years ago and the mass of the gantry was a pretty small part of the motor requirements. The acceleration of the ballscrew was a large part of the motor requirement, and this in turn related to the ballscrew inertia. Inertia relates to having mass a long way from the axis of rotation, so heavy pulleys will have an effect. If you want to pocket them out then removing mass furthest out makes the biggest difference. And larger pulleys are significantly worse as inertia relates to the square of the radius so goes up quickly.

[dazp1976]

The other thing to think about is for an axis with double ballscrews you need to be able to square the gantry. This might mean being able to rotate one ballscrew very slightly by hand (without the pulley secured) until the gantry is square, so a key way or D flat would not work as this puts the pulley at a fixed location on the ballscrew. A simple pair of grub screws allows the pulley to sit at any angle on the ballscrew.

Also on the inertia side I did the calculations for machine design years ago and the mass of the gantry was a pretty small part of the motor requirements. The acceleration of the ballscrew was a large part of the motor requirement, and this in turn related to the ballscrew inertia. Inertia relates to having mass a long way from the axis of rotation, so heavy pulleys will have an effect. If you want to pocket them out then removing mass furthest out makes the biggest difference. And larger pulleys are significantly worse as inertia relates to the square of the radius so goes up quickly.

If I had the knowledge and tools I'd prefer to drill/tap a longish threaded hole into end of the ballscrew and bolt on a pilot bore pulley. Use say 5mm high tensile. Guess it depends on machine size wether it would hold.

[JeffZ]

The other thing to think about is for an axis with double ballscrews you need to be able to square the gantry. This might mean being able to rotate one ballscrew very slightly by hand (without the pulley secured) until the gantry is square, so a key way or D flat would not work as this puts the pulley at a fixed location on the ballscrew. A simple pair of grub screws allows the pulley to sit at any angle on the ballscrew.

Shouldn't it be possible to auto-square using 2 drivers and adjustable endstops?

[routercnc]

Shouldn't it be possible to auto-square using 2 drivers and adjustable endstops?

Yes but you likely need to square it when you first build it.

[JAZZCNC]

Shouldn't it be possible to auto-square using 2 drivers and adjustable endstops?

Yes and No.?

The problem with using the switches to get the square is you are applying twisting forces on the gantry/linear bearings/ball screw combination causing friction that will very quickly rob power and lead to stalls or missed steps and excessive wear.!.

You need to set the gantry as close to square as possible mechanically ie: loosening pulleys and plates etc so there are no twisting forces on the linear bearings and ball screws. So having setscrews rather than key ways allows you to turn the ball-screw and have it spin in the pulley for fine-tuning because the belt pitch won't allow fine-tuning.

Then if required only use the switches for the very fine tuning.

[JeffZ]

Yes and No.?

The problem with using the switches to get the square is you are applying twisting forces on the gantry/linear bearings/ball screw combination causing friction that will very quickly rob power and lead to stalls or missed steps and excessive wear.!.

You need to set the gantry as close to square as possible mechanically ie: loosening pulleys and plates etc so there are no twisting forces on the linear bearings and ball screws. So having setscrews rather than key ways allows you to turn the ball-screw and have it spin in the pulley for fine-tuning because the belt pitch won't allow fine-tuning.

Then if required only use the switches for the very fine tuning.

Ah, that makes sense. Thank you for explaining.

[johnsattuk]

The other thing to think about is for an axis with double ballscrews you need to be able to square the gantry. This might mean being able to rotate one ballscrew very slightly by hand (without the pulley secured) until the gantry is square,

Which is what I do with my twin screw router