Female MMCX connector Hex Nut Size?

Was wondering if i could get some help figuring out what size is that hex nut lol. Tried looking at some charts but not entirely sure. I think it’s an M2.5 but I could be wrong.
bought 3 pairs each of the mmcx, the shorter one doesnt come with a hex nut but seems to be the same thread size.

I would guess M6, but again, may be wrong. Easiest would be to take a caliper to it.

oh god this is confusing

Nah. It is just numbers describing what to use to hold the world together :smiley:

So, if you wanted to be absolutely sure, you need a pitch gauge:

And calipers:

It’s what’s called a M3 (3mm.) Hex nut. Which is 5.3 mm measured across the flats.
Based on your photo of the brass nut it measures 5.33 across the flats. A 5.5 mm socket gives you .17mm. over size clearance . It’s called a M3 because it fits a 3 mm bolt thread. Hex nuts are sized by the diameter of the threaded bolt they’re going on. When choosing a wrench you look for a M3 socket which measures 5.5 mm opening across the flats.
It’s that simple. Trust me. Oh yeah if it’s a Chinese product it’s a metric thread. I’m a retired plumber, steamfitter. I’ve likely installed a million nuts and bolts of various sizes.:sweat_smile:


Look at that chart you provided.
All the information is there.

d = diameter of bolt ( M3)
p = thread pitch ( 0.5 mm. peak to peak)
s = nut measured across the flats (5.5 mm)
m = height of nut (not very important) (2.4mm)

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thanks! appreciate it <3 was a little worried if i missed something lol

guess this chart makes more sense now.

Glad I can help. Never thought I’d be using my trade knowledge here.
Take the headphone adapter thingy with you to home depot or wherever to make sure it fits a nut. HD usually has brass metric nuts they might be located in those specialty bins
If you can’t find brass use stainless steel… That 4.9 mm measurement is misleading it likely refers to the amount of cosmetic round over they’ve machined into the nut. It’s kinda like equations , if you know the diameter of the bolt you can find the wrench size opening measured
across the flats. If you know the wrench size you can establish the bolt diameter.

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