Re: [CAD_CAM_EDM_DRO] Bearing question for ballscrew conversion

cadman@... wrote:

> As I layout my design for the ballscrew conversion, I'm wondering if I
> need "Angular Contact" bearings at both ends. I'm thinking that only
> one end needs to have two angular contact bearing with a clinch nut.
> The other end can have a regular "single" bearing and let the lead
> screw "float" here.
>
> What does the group think about this? I have a crude ASCII art
> picture below.
>
>
>
> //////// ////////
> | | | |
> |bearing| |bearing|
> | plate | | plate |
> | | | |
> ---| | | |------
> | | | | | |
> | ------ | | --------- |
> |_| | | | | | |_|
> | XX | | | | // | \\ |
> | | |angular contact bearings-->| | |--
> | | | __________________________| | | |<---nut
> ------------------ -----------------______
>
> ______
> ------------------__________________________-----------------
> | | | | | | |
> | | | | | | |--
> | XX | | | | \\ | // |_
> |-| | | | | | | |
> | ------ | | --------- |
> | | | | | |
> ---| | | |------
> | | | |
> | | | |
> | | | |
> \\\\\\\ \\\\\\\
>
>
> It would be hard to design a clinch nut at both ends of the screw. I
> would need to use shims or something to get the spacing correct.

This is normal practice. There are some reasons to use angular contact
bearings at both ends, mostly to prevent whip at very high speeds.
You have to be very careful to never compress the screw, however.
This can be tricky under varying temperature, heating of the screw,
etc. On small machines, I think the constrained bearing at one end and the
simple bearing at the other is the best choice, as you've shown it.

Jon