Re: [CAD_CAM_EDM_DRO] Re: Taig CNC mill - Bridgeport

Guys,
I think you are missing what I am talking about. A Bridgeport Series 1 and 2 CNC were made by the thousands in the 80's. They
used stepper motors, open loop, 1/2 step unipolar drive. The two machines are identical except for the knee and table. The series
2 weighs about 1000-1500lbs more because of a larger envelope (something like 15 x 30 vs, 12 x 18 for the series 1) Most had a
rigid ram, but some had the regular V-ram style although these are much less rigid. Some have power drawbar, but most I have seen
have quick change Ericson 30 taper spindle.
These are not converted Bridgeports, they are dedicated CNC. No handwheels, ballscrews all around and 10 times better Z than
you get in ANY retrofit of a standard bridgeport head.
All you have to do is replace the stepper drivers with new ones, and put a phase converter on the spindle motor. That's it!
You can do the break by hand and blow shop air into the speed control when you want to change speeds, or it's just as easy to hook
up the air controls.
As Tim pointed out, the motors won't run at their OEM performance level, but so what? We're talking home shop here and 30 ipm
should be plenty
Someone tell me where else you can get a full size 3 axis mill for less than 2 grand?
The ONLY disadvantage is the size. Many guys may not have room. But I tell you I have a 10' by 20' with only a 7 foot ceiling
and I would never go back to my old JET. You guys with basement shops would have real trouble with it.
I don't care where you live, if you look around you will find one dead and rusting off in the corner somewhere. If you can't
find one for less than 2 grand you're not looking hard enough.
End of rant.