I got a RGB rotary encoder, it looks like it's from sparkfun. it doesn't seem to have a screw and a nut like most potentiometers. i was wondering how someone would mount a knob like this to a panel?
on the product page there are versions of the knob with the screw mechanism, but mine is like the following photo:
According to the spec sheet (from Sparkfun's product page: http://cdn.sparkfun.com/datasheets/Components/Switches/EC12PLRGBSDVBF-D-25K-24-24C-6108-6HSPEC.pdf, see section 3-9) this should have a nut (or at least a threaded bush under that knob) for panel mounting. All the other pictures show a threaded bush.
Are you absolutely sure yours has not got this? Perhaps a picture of your Rotary Encoder (without any knob mounted) could shed some light on this.
Pots come with different outlines and options. Generally, a pot like this with no bushing would be supported by the PCB that it is mounted on, which is then attached to the case. That is very common in consumer applications.
aarg:
a pot like this with no bushing would be supported by the PCB that it is mounted on, which is then attached to the case. That is very common in consumer applications.
Quite so, which is why I would be surprised at Sparkfun selling such a product to a hobbyist - after all, we don't usually mount the components on a sub-chassis and then just expose the spindle through a main panel.
So is this a Sparkfun item or just one that resembles it, but is actually an end-of-HD-TV-run from some Far Eastern factory selling them off?
If it is not a threaded bush type component then there will be difficulties mounting it to a panel, I fear 
OP where's that photo?
Ralph_S_Bacon:
If it is not a threaded bush type component then there will be difficulties mounting it to a panel, I fear
Nothing is difficult to mount when using JB Weld...
If the OP's board really does look like the one pictured, then four small threaded standoffs JB'd to the plastic of the LED surround (at each corner with the molded "dot") could make for easy attachment. Alternatively, the screw holes in the PCB could be used, along with some kind of plastic reinforcement bracket to keep it from bending.
Seriously - this doesn't look like it would be that difficult to mount.
/a picture of the OP's board would be helpful, tho.
If this is important to you, then it's time to learn Eagle and design your own PCB. I use PCBs all the time as mounts or even front panels. (OSHPark helpfully warns me that I didn't put any copper on those.)
If it's not important or it's temporary, use hot glue.
Yes, this was designed for a PCB, really.
But you could use strip board or mounting board (with just solder holes) and then drill and mount some stand-offs on that to mount to a front panel.
Frankly, if it were me I'd just buy one with a screw thread rather than all that faffing about, but that's just me being lazy. 
The first photo is most certainly not intended to mount by screwing to a panel, as the whole idea is that the circular NeoPixel display be visible.
mrtunes:
Ok - that's a bit different from the original one posted. Here's what I would do:
First, solder your wires to the board from the rear of the PCB.
Then, on the panel where you have your hole drilled for the shaft, epoxy a couple of pieces of plastic the width of the PCB, so that the PCB fits flush to the top of the plastic pieces (or near enough). The best way to do this would be to insert the shaft thru the hole, position the PCB, and mark with a pencil or sharpie each edge (or an outline) of the PCB. Then measure the PCB, and verify the markings. Then cut/trim the plastic pieces and fit them in place on the panel. If you are careful with the epoxy, you could even position the plastic pieces using the PCB as a guide, until it sets (just don't get any on the board, shaft, etc).
Once the epoxy has set up, put the shaft in place, then use a small piece of plastic as a bracket and screw it down over the back into the plastic side pieces. The first pieces of plastic are to keep the board from rotating, while the backing piece of plastic is to keep the module from falling out of the panel or otherwise becoming loose.
Variations of this idea are also possible (perhaps a couple of plastic tubes mounted so that a couple of zip-ties could be used to secure things). Alternatively, you could goop it on with some silicone (or as mentioned by others, hot glue). If you don't think you'll need to replace the part, drill the hole in the panel slightly smaller (use a drill the next barest amount down in size, then ream the hole slightly larger), and press fit it in, then use dots of epoxy along the edge of the encoder/pot and panel.
thank you for all the responses. i think i will have to order the ones with the screw mounts since I ended up with this because i relied on my local shop. especially after reading cr0sh's post, i can see just how much work this could end being!
