Ball Screw

I am using a threaded rod as an axle for a vehicle that I am creating for a project. I need that axle to go through a wooden piece and therefore I need bearings. I did some research and I found these things called “Ball Screws”. I am still not 100% sure if they are what I am looking for. So could someone please explain what are ball screws and do they act as basic bearings for threaded rods.

By bearings I mean: bearings used on shafts (Versa bearing) that are used to hold the shaft in place while the shaft can still spin.

If Ball Screws are not used for that purpose then what could I use for bearings for a threaded axle.

Thank You

ball screws are not bearings,
as the threaded rod turns a rotationally fixed ball screw will move forward or backwards along the rod

Thank You , so in that case do you know of anything else that would act as a bearing for threaded rods?

I would just use a standard bearing that is the right size for the rod. Alternatively you could make a threaded bushing that threads onto the rod and sits in the bearing.

don’t know about a specific cots part you can buy for it, but you can attach a ball screw to a bearing or something like that in a sketchy way but i can’t guarantee it’ll work well. i found this thread just now, maybe it’ll help . Why do you need to use a threaded rod?

Would having a standard bearing work? Since its threaded and not a circle or hex??

Its for a project - threaded axle because I am using wingnuts on the axle as brakes

If your not going for super precise placement it would work with maybe a little rattle. If you need a more precise fit I would recommend using the bushing method.

Alright thanks a lot!

I just found these on VEX

could they work with a hex bearing?

The standoffs will not work as bearings. Us a standard bearing as other people have suggested

Could a threaded rod go in a standoff and then a standoff inside a bearing?

How long does your mechanism need to work for?

What size is your threaded rod?

My mechanism is just an axle (threaded rod) I just need a way to have it go through plywood and still spin - so have like a bearing maybe?

Threaded rod that I want to use is 1/4 inch

axle for a vehicle

How long does it have to work properly? A few hours so you can demonstrate it at school to get a mark? Days, weeks or months of continuous operation?

Well I just need a design, I am not going to actually prototype it, probably weeks I would say.

However would the standoff into bearing work?

My suggestion is to buy 1/4" solid rod, and use a die to cut threads in the end as long as you need for the wing nuts, but not so long as to have threads in the bearing, or at least not in most of it. If you have a bench vise, you can get a tap & die set starting around $30, or individual die and handle for probably half that.

Also - you may find that a bronze bushing is adequate for your need, rather than a full bearing. These are available at most hardware stores. The bronze is impregnated with oil, so its self lubricating; you just want to make sure the shaft is smooth to begin with where it meets the bushing: I’ve found a minute or two with a piece of ~100 grit sandpaper will do the trick.
[added even later]: I meant the bronze bushing to be used in conjunction with solid shaft, not with threaded rod. Threaded rod spinning in a bronze bushing with any load will cause rapid bushing wear.

1 Like

Thank You

If you use a ball bearing for 1/4" shafts, you could put the 1/4" threaded rod directly in it. The inner race of the bearing is meant to spin with the shaft. It is also much harder than your threaded rod so it will take much longer than weeks to damage the bearing or the threaded rod.

The “outside diameter” of the hex standoff is likely to be some weird size that you can’t get a bearing for.

Just don’t use solid brass or bronze bushings as bearings. The threaded rod will chew it up pretty quickly.

Hmm okay thanks. I mean I could use a band saw and then make the shaft really small so that it only covers a bit of the threaded rod. Then use that shaft; tap it, put the threaded rod into it. Next have the shaft in a bearing.

Would that work?