Centec 2 ballscrews

[jonnydeen]

i did a few drawings of my concept (has anyone seen this done before?)


the first 2 show the ball nut and a mount i designed to utilize the original leadscrew mount holes



i then proceeded to modify the old ballnut mount i designed into a ballscrew mount. notice how the new mounts are 0.01mm off concentric which i feel is negligible and with adjustment can be completely overcome


the screw mount was then further modified to allow attachment of a stepper via pulleys. it was also extended to clear the lip at the back of the knee (see second pic below)


and finally with a nema 23 added for good measure


still have to draw some pulleys, a ballscrew and a few other components. more to come soon


so...

any critical thoughts on this design?

[Jonathan]

I would mount the stepper motor to a block of aluminium since the posts are not particularly strong, wont conduct much heat from the motor and also look like a grandfather clock. Also you might have difficulty fitting the belt/pulley between two posts? It would certainly limit your choice of ratios.
Probably negligent, but instead of making the ballnut mount match the circular profile of the nut, I'd make the mount closer to a rectangle so it fixes to a greater area of the bed since that should be stronger.

[jonnydeen]

I would mount the stepper motor to a block of aluminium since the posts are not particularly strong, wont conduct much heat from the motor and also look like a grandfather clock. Also you might have difficulty fitting the belt/pulley between two posts? It would certainly limit your choice of ratios.
Probably negligent, but instead of making the ballnut mount match the circular profile of the nut, I'd make the mount closer to a rectangle so it fixes to a greater area of the bed since that should be stronger.

fair points, i will certainly be changing the ballnut mount but the screw mount is, although debatable in need of more thought (access to y axis gib screws has been somewhat compromised)

cost also needs to be taken into account so i may well use standoffs just to get the machine running and then cnc a new mount

[mikegcnem]

fair points, i will certainly be changing the ballnut mount but the screw mount is, although debatable in need of more thought (access to y axis gib screws has been somewhat compromised)

cost also needs to be taken into account so i may well use standoffs just to get the machine running and then cnc a new mount

Please you are back on your project In the meantime soldiered on and after a year. Just fitted a ballscrew to the feed of my Centec 2A. It was a 2 but I managed to get a 2A body that fits the base and as expected all the upper parts. Ran with a borrowed Stepper Motor and a battery drill. My electronics associate in this project is working on the controls. Only current problem is when doing some milling with the drill as power to form key shapes in end of 1/4 inch rod a possible vibration from the cut dislodged the circlip at the driven end. Looking to see if alternative ends possible.
Mike