I'm learning guitar, been playing for a few months now. I have a used Ibanez RG170R and it works great except I cannot for the life of me figure out how the whammy bar is supposed to attach to the bridge. From what I hear most of them just screw in, but this one has no threads... I can put it into the socket, but it doesn't fasten or lock or anything-- i.e., if I were to turn the guitar upside-down it would just fall right out, and if I hold the guitar upright (in playing position) it's so loose it just rotates so it's pointing straight down.
Am I incorrect in assuming that it's supposed to fasten somehow? All I can think of is to wrap a peice of tape around it so it fits more snugly into the socket... It's unlikely that I'll use it all that much, but it would be nice to know how it's supposed to work.
It sounds like your guitar's bridge might be missing a piece. Post some pictures and we can help you more efficiently.
"Maybe this world is another planet's hell?" - Aldous Huxley
I know on my Fret-King's Wilkinson trem, there is a tiny pressure screw that you tighten from the side. Otherwise, it would act much like you describe.

Look closely- if you see a screw that looks like it would not attach the bridge to the body, that could very well be a pressure screw like in my Wilkinson.
Sturgeon's 2nd Law, a.k.a. Sturgeon's Revelation: “Ninety percent of everything is crap.”

Why, yes, I am a lawyer- thanks for asking!

Log off and play yer guitar!

Strap on, tune up, rock out!
Your guitar, since it doesn't have an Ibanez "Standard" screw in tremolo arm, was made during or after 2002 and will have a FAT-20 trem, which has a push-in arm.

What you most likley need need is the trem arm bushing, a common point of failure on Ibanez push-ins.

Call Rich at Ibanezrules.

“Ignorance more frequently begets confidence than does knowledge.”
Charles Darwin
Ah, that makes sense. It does look like I may be missing a piece. I couldn't find a pressure screw like dannyalcatraz suggested, so that must be it. Thanks for the help!
I'm pretty sure it just slides in and out like that. That's how it always was on the RG120 I bought new way back when I was first starting.
Spin 'round carousel when your horse isn't screwed in.

My band:
Fractured Instinct
(For fans of Death/Groove/Prog Metal)

Ibanez RGA42E
Ibanez S420
LTD H-301
Ibanez RG520
Peavey Predator USA
Douglas Grendel 725
Line 6 Pod HD500X