Pickup Polarity Question

I built a parts caster and wanted to use some pickups I have laying around. I have a Keystone bridge and a Fender 62' neck. I wired it up, and they are out of phase with each other. The middle position is less than 1/2 the volume of either pickup individually. Is it simply a matter of reversing the wires of one of the pickups wired to the pots, or are the 2 not compatible?

Yes.

The neck pickup usually has one wire connected to its case, that is cold/ground. Test ground continuity with meter. Some neck pickups are 3-wire and can be easily reversed.

The bridge pickup is usually grounded via a separate wire to the mount. It grounds the pickup base and bridge plate. So it should be easiest to reverse the bridge pickup.

Usually the Keystones have a dedicated bridge plate ground. You have 3 bridge pup wires right ??

Switch the black and white (coil wires), the blue is the base plate ground and remains on the back of a pot.