I just finished soldering my custom guitar yesterday, and I strung it and plugged it in today.
As soon as I plugged it in, there was a ton of buzzing that decreased slightly when I put my hand on the jack plate or the lead, but was still loud. I have two metal toggle switches in my guitar and whenever I touched them, the buzzing worsened.
It's a Strat using S-Tastic Expanded wiring seen here (scroll to the bottom):
Hi minions - OK its noisy, but does the guitar work correctly in terms of the pickup sounds in each combination? If its not obvious, tapping the pup pole pieces with a screwdriver will tell you which are active, by a clear thump through your amp.
If the sounds are not right then its a matter of tracing an error in the wiring. But if it basicly works but is too noisy, then:
I notice that the diagram does not include the non-signal grounding to the pot cases and bridge. If you don't have this, then it will explain your problem nicely. All you need to add is a wire that goes from your SG ground point, to each pot case (by any route), and push/pull pots usually have a handy solder tap at the back of the switch to attach to. Also a wire from SG to the bridge is needed.
Do you have shielding on the back of the pick-guard and cavity? - highly desirable, and contact with this will ground the toggle switch cases, so touching them will not affect noise. If you don't have shielding, Id strongly advise it, at least to the pick-guard. This would mean disassembling, but you would be able to keep the wiring harness intact. But if for some reason you cant do that, then a grounded wire soldered to a washer around the toggle switch shafts will help.
tapping the pup pole pieces with a screwdriver will tell you which are active, by a clear thump through your amp.
I have done this and here is what I've found:
Sometimes the pickups do work, i.e. are active, and sometimes they don't. When they do work, the sound is faint. I'm not sure exactly as to the cause, however, the middle pickup works the least amount of the time.
I believe this may be due to either a faulty pot or solders on the pots because the middle pickup is wired to the push/push switches on the back of the pots.
Also, the volume pot does not work as a volume control, i.e. it is always on 10 regardless of where I turn it.
Well, from your initial descriptions, it seems there are some major issues with the basic wiring - beyond those related to shielding, or to the extra bare wires and wires to the pot cases (which do not carry the signal). This doesnt mean there is a huge difficult problem however - it could be just one wire missing or misplaced. My guess is that it is one of the wires on the diagram that connects to ground is not so.
SG is for star ground - just a point where all grounds connect. Actually, you can have sepearte wires from each grounded point to there, or run a wire that links them, or a combination - the point is that all points that need to be connected are connected.
If you pickups have two insulated wires plus bare, then the insulated wires follow the diagram and the bare wires go to ground (SG)
If you are stuck, how about some tests?, do you have a mulimeter? If so, set to resistance, using the 20k range, and connect across a guitar cord plugged into the jack. Set volume to max and select each pickup one at a time. The reading should be about or slightly less than the Ohms the pickup, ie probably 5k to 10k depending what you have. Parallel settings should be a half of that, series settings of two pups should be x2 ish. If you get much higher readings (maybe need to go up to the 200k or 2000k range), then you have missing connections in your guitar.
If the single pickup readings are OK, then sweep the volume control from max to min. the Ohms reading should firat rise to about 1/4 of the pot resistance (eg 125k ish for a 500k volume pot) then fall to zero at min volume.