First off the fork im looking into rebuilding is a Spinner Edge 4. Its a bike that at this point I don't want to put much money into. The fork feels unresponsive, it suspends then doesn't seem to bounce back as fast as some forks I use. I am a very competent mechanic, but typically deal with road and rigid MTN bikes.
So could someone explain to what purpose you overhaul forks. Hubs are obvious why overhauling/rebuilding is necessary, but I cant see why forks need to be overhauled, something about seals and things. Or if that's just the way some forks feel? I understand some use oil and some are air. So what I like to call "technical general" info or "low down" on forks and function internally would be excellent. I know some forks are just disposable but the one I have is hardly used. Any info is greatly appreciated. Please no "get a new fork" or "take it to a shop" suggestions since I have plenty of suspension forks laying around but want to get into this, Im long over due. Thanks all! I also posted in the Mechanics forum.

I'm not familiar with what an Edge 4 is; but I'm looking at the Spinner site now at an Edge AL1 and have to assume it's just a newer Edge. This appears to be a base no-hydraulics fork. What you would find if you opened it up is a spring or spring/elastomer stack and grease lubing the bushings - - much like lower-end RSTs (which I am familiar with). Since there are no hydraulic (rebound damping) circuits to go bad, there are no shim stacks, o-rings, cartridges or any of those other Swiss-watch parts to service inside. If any dirt has gotten past the stanchion wiper seals, the grease can get gunky and can start gumming up the works but that's about it.

SOOOO . . . if you want to tear it down: pull it apart; clean out all the old grease; clean and relube the wipers (since you don't have replacement seals; and regrease with a good-quality NLGI 1 grease. NLGI is a lighter than NLGI 2 automotive chassis grease and is approximately what the consistency found in Manitou PrepM grease. It is generally sold in automotive and industrial settings as a cold-weather grease.

I like Amzoil Snythetic Multi-Purpose NLGI 1 grease; it's light, slippery and I get a whole grease-gun tube for less than a few piddly ounces of PrepM (if you can even find it). [I learned way too much about greases when I was looking to rebuild a downhill fork to sell.]

Good luck.