Bridgeport Disassembly

March, 2006.

As part my scraping of a worn Bridgeport milling machine back to original precision, I had to disassemble the machine components. Disassembling a Bridgeport mill is also sometimes necessary to move it into a small shop space or through a low doorway, or when using small vehicles.

Until I can get my photos and detailed descriptions posted here, let me just leave you with a list of the disassembly steps I used:

• Table: The table is the most complicated. The disassembly order is: nut on right handle, handle, knurled stop, scaled dial, cap screws on bearing plate, bearing plate. Do this on both ends. Remove table gib screw and table gib. Attach hoist (I used a sling through eye bolts on T-nuts on the table). Slide table horizontally off dovetails.

  You can also slide the table onto a sturdy workbench instead of hoisting; crank the knee up or down to match the bench height.

• Saddle: To get the saddle off, first remove the crossfeed ("Y" axis for the CNC-minded) leadscrew bearing plate capscrews and the plate itself. Remove the yoke capscrews, yoke, and both leadscrews. Remove the saddle gib screw and gib. Slide off saddle (I could just lift it solo, like a sack of cement).

• Knee: Swing ram around to provide clearance. Crank knee up completely. Remove gib screw and gib. Hoist knee off dovetails.

• Ram and Turret: I've not removed the ram and turret, but I am told there's just a spider under the 4 bolts on the turret after you remove the bolts. To hoist, I would use a 5/8 lifting eye in the threaded hole on top of the ram. Or a sling snugged fore and aft.

If you have no hoist, you can improvise lifting heavy pieces by clamping on lumber or SuperStrut with C-clamps, like a medic's stretcher, and having sturdy human helpers lifting on each stretcher corner. Like a king in a sedan chair.

Don't mar any precision surfaces. On most components, almost all surfaces are precision!

The gibs and ways will be quite a mess with oil or grease. The knee will likely be filled with old chips. Kerosene, nitrile gloves, and a carton of paper towels are good for cleaning the components. The big polyethylene mortar mixing tubs sold at the building supply store are a good "wash basin".

Be prepared for surprises. I discovered the overworn saddle gib on the old machine I bought had been shimmed ... with a rough piece of metal pallet strapping.

If you want to refinish or paint an old machine, it is best done while disassembled.