# How to design a precision (small) axle?

For a mechanical design, I would need a small/light axle, having high precision (as less loose as possible and reduced drag). With precision, there is not a very strict definition, however, I target ~0.2º of radial rotation (axial movement is not that an issue).

The length of the axle is around 24mm, on which I would attach a few elements (~50g).

The first idea is to use a bearing on each side of the axle, but I am not sure what is the good practice for attaching the bearing.

Following is my current sketch:

The closest example of what I am doing is the axle in the actuator of a Hard-Disk, however, the bearing there is internally tapped for fixation. Most of the bearing I found on the market are not tapped. My feeling is that tapping the bearing is not a good idea.

My question is:

What are the commonly use pieces, practices, terms and fixations for this type of problem?

I understand is a quite broad question, but either I miss terminologies and in any case I did not found answers online. Also, I do not need a deep answer, but some indications of where to look further.

Others possible tags: axle, matched-set

• Do you mean "axle" ? Further, what is the actual problem you are trying to solve? Commented May 25, 2017 at 13:30
• What is wrong, in your opinion, with tapping the bearing? It is tapped early in its manufacturing process before being assembled and even, before hardening. Commented May 25, 2017 at 13:46
• You can thread the axle and use a nut and locking washer, you can put a groove in the axle and use a circlip - just two possibilities. Commented May 25, 2017 at 14:24
• Take a floppy drive or a CD ROM drive apart; the bar upon which the head slides is very precise, hard, and should be what you need. As for affixing the bearings, the usual approach is a minuscule amount of super-glue.
– SF.
Commented May 25, 2017 at 15:14
• Press fits are quite common, so is Loctite on a less precise fit. Commented May 25, 2017 at 21:33