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How do I properly attach ball bearings to threaded rods? Answered

Hi everyone
I wanted to attach 14 mm ball bearings to 5mm threaded rod but I notice I can't get them perpendicular to the rod and parallel to each other resulting in a massive wobbling...
Can you please help me figuring what am I doing wrong?
I wanted to create a miniature table saw attached to a drill or other motor.
The bearings would keep the blade attached to the plate.
I've uploaded pictures I hope can help figuring it out.

Thank you, everybody for your help!



Best Answer 3 years ago

You never had a skateboard? ;)

You need bearing spacers, that's what we called them back in the days.
Available as short "rod" to go between two barings or as a "washer" to go between nut and bearing.
They are designed for the inner diameter of the bearing.
If I take your last pic I would like this, from left to right:
Nut, nut, bearing washer, bearing, bearing washer, sprocket, bearing washer, bearing, bearing washer, nut, nut.
Double nut so you can lock them against each other.
This way all bearings and the sprocket will stay parallel to each other and aligned with the rod.


Answer 3 years ago

Hi Downunder35m

Thank you for your answer!

I fact I never had a skateboard :)

I'll check for those washers, thank you!

Josehf Murchison

3 years ago

Your question had me going there for a bit.

Those are called "Sealed Bearings", and they are meant to be press fitted onto a shaft.

There is a gap between the seal bearing's ID, (Inner Diameter) and the threaded rod's OD, (Outer Diameter), I can't tell from your pic but it can be as much as 0.01 of an inch, this can make the bearing out of center and wobble.

You can cure this three ways.

1. A tight fitting bushing between the bearing and the threaded rod. (This is called a threaded spacer.)

2. Self centering nuts. (Nuts tapered on one side like the lug nuts on a car wheel.)

3. Self centering bearings. (I know you can get these from a farm supply.)

jaypalJosehf Murchison

Answer 3 years ago

The PF-250 would match my project flawlessly!

Perhaps I'll consider it in a future upgrade.

I really miss my high school lathes... :)

Josehf Murchisonjaypal

Answer 3 years ago

I have a small drill press I bought for $30 I use as a lathe.

For small things under 1/2 inch it is perfect.

I have used it to make Armour Piercing Bullets, Firing Pins for rifles, and a number of other parts.

jaypalJosehf Murchison

Answer 3 years ago

Hi Josehf

Thank you for your answer!

I also thought about the difference in diameters but never considered it too seriously. Perhaps I should. I'd prefer to press fit, but I have no precision tools to create the rod. I'm going to check for 1) and 2).