What Herb said...and plenty of nuts bolts & washers. Do you have a proper center bearing yet? I can recommend something but it seems that when I do that any more, some whippersnapper has a "better" idea. Let me know if you want my idea.
A 3/8" Phono Jack male & female (if you can find 1/2 " it would be better) for a center pivot with track wiring capability. One of these could be modified for a gearbox but I have always used "armstrong" turntables.