Another 60/40 post

OK i got my ebay 60/40 about a week ago and i have been putting it together slowly. I have found i have had to run it at half the speed they say it should run to stop it grinding and stopping. So anyways i just been down to the cave to have a better look . I took the stepper motor off the X and the axis is very very stiff to move over by hand ( had to use 2 hands to push it ). This must the making the motors lose torque and stall im thinking?

So i removed the locking nut off the spindle and undid the bolts on the runners, pushed the X over again by hand AND n change sill as stiff. So i started pulling it back and the outer bearing fell out on the side from the motor fell out ( inner one still in place ) and wow the X slides so easy now. i can push it with 2 fingers.

So the outer bearing cant be lined up with the spindle so when its pressed in the spindle is binding on the bearing. Im Glad it was easy to find. All i have to do now is work out how im going to fix it. Also i think it may be the same one the Y as well.

Any one any ideas ?

Thanks mick . may help some one else having the same problems

this is what im talking about . I guess im gonna have to remove material from both side to minimize the slop it the bearing. I think it cant be much i need to remove

Attachment 13226

Before I get the grinder out do you think it could just be an alignment problem. It's out in the up down axis. Do you think I could have some movement on the ball screw mount to square things up?

I did this same thing today, but different conclusion.

First off, I can just about push my main axis carriage along the ballscrew. BUT (others will tell me if I'm wrong here) being able to push along the ballscrew shows how very low friction they are. The fact that a little more preload on the bearing stops this, does not mean a big problem, what is important is how easy it is to turn the ballscrew.

Anyway, I had been plannig to take the balls out of my ballnut (from the videos eddy pointed out), but I decided that the axis felt OK mechanically and now I think that it is a driver problem.

For info, at the motor end there is a floating bearing. At the other end are 2 standard roller bearings which take the load in either direction.


edit: just noticed you were talking about 6040 X axis, not British. My cross axis is easier to push than the long axis, as it should be given the lower inertia. Doesn't change what I wrote above about my machine, but you may well have an alignment problem with yours.

My thought is that mine only got very tight when the ball screw was attached to bother fixed bearing. The outer bearing when It pops out you can see it's lifting up higher than the hole by about. 0.25 mm, you can get it back in the hole only by using the locking nut to pull it into places but then the ball screw is very tight in the bearing. Can't be rite forcing the bearing over the shaft into the hole, it's putting downwards force on the screw. Making it squeezes up on the bearing. Hope that makes sense. Lol

yeh, that's wrong. my bearings slide in and out nicely.

Eddy had similar problems with bent ballscrews, and bent spigots.

OK so today i striped mine down and rebuilt it, it runs nice and smooth now and I can run it alittle faster but it still stalls if i run it at recommended speeds . I personally feel this steppers are not upto the job ..i have some nema32 450 i could try on it just to see if that changes things. what do you think?