Bridgeport power table feeds, AKA more masochism, AKA The Next Big Thing

 The old Bridgeport power table feeds came in several different models.  Mine is the first one they came out with, which is the Model 6F, generation A.  First, right, okay.  Wanna bet the serial number is dumb too? 😂

So this beast consists of...

1. The motor/control assembly:

elegant, wot? >_<

 Note the shaft passes through (as it does all with power feeds) for the handle and dial.  This will come up later.

 This unit contains the oil-filled gearbox on top - note sight glass - and below that, the electrical box with a speed control knob and a fast-traverse switch.  The motor is at an angle behind it.  Why at an angle?  Who knows?  Perhaps to make it less obvious and so make the whole box less bulky looking... maybe.  Maybe it was just convenient.

  The direction lever passes through the gearbox (where it engages or disengages the motor) and enters the electrical box on the bottom via an o-ring, where it actuates forward or reverse motor directions.

 The motor is of the "field-wound DC" type, which just means it's a normal commutator-and-brushes DC motor, but the field is provided by a separate winding, not permanent magnets.  Any DC motor drive will have a field output, usually adjustable as some percentage of the line voltage.

 The limit switches are also wired back to the motor drive, which means that fat cable between the two units has a lot of wires in it.

 The reason any restoration job is so dire is that Bridgeport, in their infinite wisdom, put the gearbox above the electrical housing containing the switches and speed knob... the gearbox full of oil... the gearbox full of oil with 1970s (Buna-N? Neoprene?) O-rings and seals.  So of course oil leaks into the electrical box of the motor assembly, destroying wire insulation, the potentiometer, and most likely the pushbutton and limit switches too.

2.  The motor drive (electronic PCB) is located in a separate box, mounted to the column:

could they locate the power switch
in a more inconvenient place?!?

The electronics are from 1972.  That's too old for the aluminum electrolytics in it, for starters.  It's possible other things are wrong too.  The stud-mount SCRs and rectifiers are obsolete as hell.  OBTW, it plugs into 120, doesn't pull much current.

 None of that matters because, ta-da! this kind of motor control is still needed today, so suitable drop-in motor drives are available (I like Minarik, not sure if still in business) for $50 - $100 new, cheaper used.

 Instead of external limit switches, it has a moveable rod mounted on the table, with adjustable stops on it, which in turn pick up a whatchamacallit on the saddle when the limit is reached.  That fixture also provides for physical stops mounted in the front t-slot.

in lieu of any guidance from
Bridgeport, I'm calling that
thing 'Fred'

 One end of the rod is attached to the direction-selecting handle on the power feed. When the rod moves, it pushes the handle toward center-off.  The actual switches are inside the electrical box.  That shaft through the gearbox into the electrical box always ends up leaking oil (after thirty years or so) through its o-ring seal, because all they had in 1972 for oil seals was neoprene or Buna-N (AFAIK, plz correct me if I am wrong).  Both exhibit aging (AFAIK).  Viton does not.

The other end of the rod used to hang out into free space, which bugged me until I fabricated a little support for it, mounted into the front t-slot.

 "Why not just replace the funky old Bridgeport power feed with a modern Servo or Chinesium Servo clone?"

 That was my first question to my benefactor, from whom I purchased the mill at a steal.  Despite being a professional machinist and tool & die maker, he hadn't gotten it done in a lot of years so I figured Something Was Up.  He patiently explained that Bridgeport, in their infinite wisdom - again - had made the lead screw shaft differently, depending on if it was with or without a factory power feed.  All of the aftermarket power feeds are designed to "drop in" (with some fiddly work) on tables that never had a power feed.  So none of the aftermarket  units will fit the shaft of a Bridgie that previously had a factory feed on it.

 My benefactor had already started on an adapter to help with this.  I have it, and it still needs a spot of work including some broaching for a key.  However, I looked at the whole situation, including the fact that the drive itself was Tango Uniform, and decided the shortest path would be to rebuild the factory unit; rebuild it mechanically, replacing o-rings and/or gaskets, and of course replacing the actual motor drive electronics.  The new board being smaller than the old board, it will fit neatly inside the stock enclosure.  In fact, that's where it's been stashed for years, so it wouldn't get lost or broken knocking around the shop.  I have written destructions from someone else who did this, including illustrations, wiring diagram (!!) and the like.

 Okay, so I'm still working on the outriggers for the hoisting cart, and those are mostly waiting for money and steel, as usual.  But once that's in the bag, this is The Next Big Project.  I might actually have to write down an order of battle for this one instead of just winging it with most of the stuff kept in my head. That trick only works on really good days, now. >_>