Hey guys.

I've had an Epiphone SG Special for a while now, and although it's a cheap guitar it's the nicest guitar in it's price range. This isn't my main guitar, but I would love it to be one of my main ones.

The main problem is the neck. It doesn't let the tuning hold that well due to the bolt-on. (The necks bends when I hold a chord too tightly).

So if I glue on the neck joint, and then bolt it back on, will that help at all?

If not then I wont bother, but if it'll help secure up that joint, then it'll make this guitar great.
If the neck is bending when you grip the neck tightly, 1) you're obviously holding the neck too tightly and need to loosen your grip and 2) the truss rod must be really loose if there is that little resistance. Neither problem will be solved by gluing the neck in place.
It's not the act of gripping, it's the fact that the neck bends easily in the joint, I just tend to play a bit over the top. No point playing an SG gently...

I suppose it's not the neck bending, it's the neck leaning?
sounds like the bolt holes are too big for the screws so there is play. i would maybe put a little gorilla glue on the screws when you put them in. tighten them, then the glue will expand and hold. i love that stuff. but it will still look like a bolt on, the bolts will be glued in place and have no play