View Full Version : Retrofit questions Boss 5,6

11-21-2007, 11:09 PM
This was posted at the Bridgeport mill forum and suggested I post here.


I have two Series 1 BPT's, one BOSS 5 and one BOSS 6. I've had the BOSS 5 since 1982 (bought used) and bought the BOSS 6 new in 1984ish (last of the steppers). Both are pretty much box stock, so you can imagine the pile of bad transistors and bridge rectifiers I have. I buy the transistors by the dozen at my local elex supplier.

I got used to replacing the transistors, but my BOSS 5 now has a bad ERS board, and the BOSS 6 now has a bad ZDI board (I think). I'm considering (strongly) replacing everything from the steppers out. I'm pretty good with electronics, mechanics and computers, but I have hundreds of hand written Gcode programs I run production with, and can't afford the time to rewrite them all. All my programs are on disc (hard/floppy) and I load them via RS232 at a rockin' 1200 baud using good old PC-TALK. Will the aftermarket software (Mach3, etc) load these old programs directly (without a bunch of edits) and be runable, or am I looking at a lot of rewrites? Any recommendations on which software package would be the most compatible with my old programs?

The BOSS 6 machine has Haas rotary table as a 4th axis. I use M51 to turn control over to the Haas, then the Haas signals the BPT when it's done. Do the newer software packages support M51? I have a production part I have run for 15 years with that setup, and would hate to not have it work. OR...Can I control this Haas stepper directly as a "true" 4th axis, and eliminate its control as well?

Should I bite the bullet and fix what I have or end the insanity and pull the plug on the BPT controls? With 2 machines, obviously price is an object, but it seems like a financially sound move (read that affordable) to consider products such as Mach3, CNC4PC C11G board and Gecko drives.

I design in AutoCAD 2002LT and would love to be able to dump the files into something compatible. Thanks for any insight you could send my way!


11-26-2007, 03:15 PM
I have done 2 Ajax retrofits on Boss 8.0 machines
But these had the Dc servos on them
Total cost per machine came out to about $6000 ea
We started having major problems from the old electronics
It finally became a nightmare, didn't know when it would go down
or if it would come back
Dont know if the Ajax can run steppers
I would look around and see who makes controllers,
power supplies, and driver cards for steppers in your
power requirements for the motors you have
Do a search for Keling Inc for parts and stepper world has a
good tutorial for how to power steppers
Servos cost too much for that old machine
Run the motors you have and upgrade the electronics
Those old Boss machines had good Iron
But the old electronics really are a PITA!!!
Might help

11-26-2007, 06:16 PM
Thanks for the response. Didn't realize that they didn't get it right by the time they got to the BOSS 8! I couldn't see myself buying any other brand, since my co is IN Bridgeport, but the manufacturer shot themselves in the foot when it came to support. I was lucky to have a couple of friends who worked at BPT Machines, and as a result, learned how to fix these things myself. You are right about the cast iron. They made the best machines...mechanically. I have a 1940's vintage BPT mill...it's older than me but is still accurate!

Thanks for the leads on the stepper stuff. The motors themselves seem to be fine. Neither machine ever lost a step. They would just quit whenever they felt like it...especially when hot. If properly matched, the new stepper drives available should be infinitely more reliable than the original electronics...someone correct me if I'm wrong there! The big thing is the elimination of almost everything in the big cabinet, and replacing it with a PC. I think my cell phone has more computer power than the LSI-11 based system! If nothing else, diagnosing a problem should be simple by comparison.

Thanks again.