Securing low-speed rotating assembly

[norry]

I think I may know the answer to this one, but can't hurt to ask the experienced guys first.

So my girlfriend's brother made her a nifty little setup to hold her knitting yarn - it rotates to dispense the yarn. Works well, but the rotating assembly is secured to the base with a bolt, a few washers, a nut, and then a nut with 'ears' on it you can turn by hand. The problem is that this tends to come loose as the device rotates. She could set it up to turn the other direction, but (a) prefers it the way it was, and (b) wouldn't this end up tightening it until it wouldn't turn well?

The solution I had in mind was to remove the nut with the ears, put on a second nut identical to the first, allow just a bit of slack, and then tighten the two nuts together such that the second one would prevent the first from loosening or tightening. Would this work? Or is there some alternate way I should be fastening the whole thing together?

Thanks in advance!

 

[e-tek]

No fun having to match wits with the brother - eh?!

I think you've got it right though. - or you could use a nyloc nut.

 

[buildmyown]

or if im reading this right drill 2 of the flats on the existing nut for 2 small set screws.

 

[Alchymist]

If this is set up so that the bolt is vertical with the head down, and the wingnut is to add/remove spools, just add another nut under the wingnut. Adjust the plain nut where wanted, then tighten the wingnut down on it. Finger tight should keep them from rotating.

 

[kbs2244]

Maybe file off the threads onthe bolt.
It goes so far and then spins.

 

[machine_punk]

or just locktite

 

[rockchucker]

Loctite or Double Nut.

"Set it and forget it!"

 

[1967marti]

you need to drill a small hole through the bar after the first nut and use cotter pin.

 

[norry]

Thanks for the ideas, guys!

You know, Alchymist, I was wondering about something you mentioned in your answer, which was the orientation of the bolt. The bolt's head should be at the top, right? In other words, as the device rotates, if the threaded end of the bolt is facing upright and the nut is resting on the device, that would tend to tighten or loosen it on the bolt. But if you flip the whole thing, and the threaded end faces down, then the bolt head is resting on the device and motion shouldn't tend to tighten or loosen it. Or am I missing something?

Oh, and E-Tek, her brother's a great guy. He and I were hanging out last weekend. I'd be totally fine with having him for a brother-in-law. But at the same time, I can't let this little mechanical challenge defeat me, either... =)

Thanks again!

 

[Alchymist]

1 picture would solve a lot of questions.....

 

[1967marti]

unless something it touching the bolt in question or there is quick stop and go's of the shaft, then it is the vibration that is turning the nut. If you ever work on rotating assy's that can cause grave damage if they fail (car spindles, throttle links, etc) they will all have a mechanical pin of some sort that can't remove itself.

 

[porphyre]

Nobody's suggested replacing the entire assembly with something ball-bearing based??? Comeon! Y'all could tig something together in 10 minutes and it'd last 100 years!

Anyway, doublenutting sounds like the way to go. Cotter pin is a good idea, but it'd be harder to execute. You may also want to check the hardware store for nylon or HDPE washers. Put that between the rack and the nuts and it'll spin more smoothly.

Damn... that sounded dirty.

 

[NASTYZEN]

Weld it!

 

[hawkeye2]

Can you replace the bolt with a lazy Susan bearing?

 

[Alchymist]

Nobody's suggested replacing the entire assembly with something ball-bearing based???

Hell, we're not even sure what the assembly is......

 

[Jack Burton]

I think I may know the answer to this one, but can't hurt to ask the experienced guys first.

So my girlfriend's brother made her a nifty little setup to hold her knitting yarn - it rotates to dispense the yarn. Works well, but the rotating assembly is secured to the base with a bolt, a few washers, a nut, and then a nut with 'ears' on it you can turn by hand.

What do you mean a "few washers"?

...put on a second nut identical to the first, allow just a bit of slack, and then tighten the two nuts together such that the second one would prevent the first from loosening or tightening...

A jam nut. They don't have the same profile as a regular nut but anyways, for future reference, that's referred to as "jam nutting".

If it works to her satisfaction, then leave it alone. If you wish to out-do her Brother then make a decent drawing and lets us look at it. Words are meaningless without a drawing.