Bridgeport Series 1 CNC Retrofit

I've recently been researching into this generation of the Bridgeport machine family. The Series 1 CNC/NC machines were built in the 80's with different variations of the control systems. There was a model fitted with Boss controls, which had stepper motors and there were machines fitted with Heidenhain controls, which were servo driven. I liked the idea of the Heidenhain machines with servo motors on all axis as these seemed to be a very robust system.
I'd grown tired of manually milling as it takes me an age to complete a job with any kind of accuracy, so I'd been looking for a cnc alternative when I found this:

Original image provided by seller.

The machine in essence is mechanically a full Series 1 CNC, however its given the name MDI due to its limited control capabilities. The machine was designed to be a point to point numerically controlled version and all 3 axis shared a single servo drive, which switched to drive a single axis independently. This presents a fairly major problem when it comes to diagonal and circular paths!! However, having the intention to retrofit the machine to new controls, this specimen is absolutely perfect.

There are some really nice features on the series 1 cnc. The head has variable speed in 2 ranges. The speed is accessed from a switch on the front panel, which then operates a dial pneumatically. There is a spindle brake, also driven by pneumatics. Each axis can be traversed by a joystick, which makes long moves very easy. There are handwheels that can be made use of to manually position any axis and the coordinates are displayed on the main control panel. There is also both spray and flood coolants, and a lubrication system piped through to all oiling points.

For now the machine will keep its original control system while I get some other projects up to date, but the end goal is to update the motion control to mach3 or possibly linux cnc.

For now, here are some pictures of the trauma the bridgeport experienced while trying to force it through a 4ft x 7ft doorway.......

Where's your head at?

looks like its been sick on itself...

The troublesome lump!

Carefully lifting the head

Back together

Mug is in the shot for size comparison

Whilst learning to program the machine and running some test programs I was experiencing some problems. One of which was the motor overload for the feeds was tripping out. I stripped various mechanical and electrical components down trying to eliminate numerous possibilities, but eventually put it down to the table feed motor. The current it was drawing was way in excess of the overload, therefore causing it to trip. The motor is currently awaiting repair / replacement, which ever is financially viable.

By the time I'd taken almost everything apart the old dear was looking quite dirty and neglected, so I set about a cleaning and oiling operation:

Looks a lot better don't you think?

So here we go... I've been pondering over this retrofit for well over a year now. The power supply design for the new servo drives really got me confused. I have had a lot of help from some really great guys on the electronics forums, and now I have a working system, subject to some more testing.

From this:

To this!  The partially completed control:

Just to prove that all the hard work was worth it. Dry run: