This is a cheap and easy to make knob, using just an ordinary plastic soft drink bottle top, a bolt, a nut and two washers.

It is especially suitable for projects where a bolt needs to be turned to adjust something.

I'm actually surprised that a similar instructable has not yet been published, as it seems such an obvious idea. My sincerest apologies if it has indeed previously been published and I missed it.

Step 1: The Parts

The picture shows all the parts necessary. Actually bigger washers would be better for a tighter grip on the bottle top.

Step 2: Preparing the Bottle Top

Just drill a hole in the centre of the bottle top the size of the bolt you're going to use.

Step 3: Assembly

The first picture shows the order in which the parts fit together. Then just tighten the nut very tightly. A lock nut is preferable, and you can of course also add glue to help avoid slippage. I usually use an ordinary nut, and lock it by damaging the bolt's thread beforehand with a metal punch (second picture).

Step 4: Finished

The first picture shows the finished knob. You can of course also use different size tops (second picture) for the appropriate torque/control you need.

<p>There's soo many articles on what to do with plastic bottles out there, but hardly any on reusing the caps! Great little instructable this, can't believe I never thought of it. Thank you for sharing this </p>
<p>Guy90, thanks. And it's also very satisfying to find a use for common items like these. It seems a shame to just throw them away. </p>
Excellent re-purpose! I'll be using this for my homemade pinhole cameras. Thanks for sharing your idea.
<p>Much appreciated, Uncle Kudzu!</p>
<p>This is a great idea. I think I would pack the empty bottle cap with an epoxy putty for a permanent fill to make it a real handle cap/knob. Thanks.</p>
<p>Catlinsdad, you're quite right, using epoxy putty or glue to fill the cap should work very well.</p>
Great job repurposing a simple item. I wish I had thought of it. It's so obvious now that you point it out.
<p>24Eng, yes, it has always bothered me that bottle tops just get thrown away, and this is at least one way in which to use them again.</p>
<p>I did a variation a wood insert once, worked great, very durable.</p>
<p>Thanks very much for your comment, BeachsideHank!</p>

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