Bridgeport CNC Series 1 vs Series 2

[jshank]

Hi,
I am looking for information as to what would be the best Bridgeport candidate for a cnc upgrade to be used in my home hobby shop. Searching through some of the past post it seems as though starting with a cnc machine and upgrading the electrical / control side of the machine would be the best approach as opposed to converting a standard machine.
What are the differences between cnc series I and series 2?
What are the differences between Boss 1 through Boss 9?
Any information on what to look for and what to avoid would be appreciated.
Thanks, Jeff

[wcarrothers1]

Don't forget about boss 10..

I can't tell ya what the difference between S1 and S2 might be.

How ever. After getting my S1 boss 10 setup for dirt cheep (ie less then most manual S1 or S2's) it was dirt cheep because of being CNC I guess.

But either way if I were to do a conversion it after getting mine I'd say look for a boss machine. If nothing else you will already have something that contains all the movement ball screw type parts. Long as the machine is in good shape that should get you off to a head start in the conversion.

I was planning on converting the drives of mine over to something (since my other machines run Mach3) but people here convinced me to at least try the old drives and I've kept them. Kinda a bonus seeing I can run 2 machines at the same time and if converted I could only run 1..hehe

They can be querky but do work and at least mine works very well. Consider what I paid for it, it works extreemly well.

Do some times wish it had some manual handles though...

b.

[jholland1]

Welcome jshank
I am a newbie on this forum also but have long association with step motor driven machines, mostly Bridgeport Boss.
History
In 1970's Bridgeport Machine employed Digital Equipment Corp (DEC) to design boards and software for an existing line of numerically controlled step motor driven machines using perforated tape as memory for parts program. The Bridgeport Operating Software System was christened Boss. Before Boss the nc machines totaled perhaps 1000. The Boss 3 machine hit the market around 1977. Memory was about 8K. The Boss 3 would drill holes, cut straight lines, do diagonal moves but would not cut complete circle. The Boss 4 followed with partial arc function. With the Boss 5 complete circular interpolation was possible. Boss 6 added more features and 12K memory.
Boss 3 and 4 frames were usually a modified v-ram Bridgeport frame. The knee had wider ways and was always chromed as were all Boss machines. The saddle was rectangular. Table was deeper and shorter than conventional BP. Ball screws were present x,y,z axes. These were called series 1 cnc machines. Serial numbers were stamped on forward section of knee. For production purposes most shops wanted a fixed vertical head and more clearance between spindle and table. This resulted in rigid ram introduction. It was much less versatile than v-ram since head would not swivel and tilt. Almost all rigid rams were Boss 5 or 6. The series 1 machines had working envelope of 18 inches x, 12 inch y, 5 inch z. Of course the knee on all could be elevated or lowered. A larger machine was introduced-the series II. Envelope was 30x15x5 inches. The knee had air assist to reduce load on leadscrew to elevate table. Series one machines scaled about 3000lbs. Series II about 5500 lbs. Step motors, drives etc were the same in series 1 and II. Total production of both series about 8000 machines. Lots of machines are still around.
POWER
Boss machines were built with multitap 3 phase transformer to allow input power ranging from 200 to 600 vac 3 phase. Below this transformer were 3 reactors which conditioned power for the step motors. In the lower right of transformer cabinet was 1 kva transformer partially dedicated to step motor power and control functions. In the control cabinet was a large card cage containing operating system boards using 5 and 12 volt dc power. A large power regulator system was to right of card cage. Above all of this a fixture holding 7 large dc capacitors for axis drives. 4 bridge rectifiers were heat sink mounted. One each for x,y,z axes and one for 12 vdc power. Also packed in were 2 transformers one each for 12 vdc and 24 vdc power. Wires were a confused mess and components hard to reach for repair. Step motor drive power was routed to swing out door on control cabinet. This had 3 SMD (step motor drive) cards. An additional card -ACC- was present to regulate dc power to drive components. Above and beneath these cards were extruded aluminum blocks which contain drive transistors. These take the shock load of power switching and have the shortest life of any solid state component. Fuses excepted. Most controls for step motors are designed to take step and direction signals from 5 vdc source. Boss does not. My company Slo-Motion Controls-Machinemaster-designed and sold kits that allowed pc to operate Boss using our boards. Others followed. Still other companies, notably Centroid, offered upgrades costing $12K to convert machine to dc servo motor drive with encoder feedback.
Entry level cnc knee mill
The Boss series is a great way to go. Lots of them with pretty cheap parts. Also user groups. You should have no problem finding a good machine at a good price. Were are here to help.
jh

[cut more]

More on Boss Series 1 vs 2
I have a series 2 Boss 8.
1 big difference between the series1 and series 2 is that the series 2 has box or square ways on the Knee, x and y axis. This is more rigid than the dovetail ways of the series 1.
I am not sure if the boss 7 has servo motors but my boss 8 and later Boss machines have servo motors instead of stepper motors.

I have seen quite a few Boss machines go for next to nothing, I was given 2 working series 2 machines.

I agree that the best route is to look for a machine that is already a cnc machine and that will save you a lot of time and money.

Cutmore

[jshank]

Thanks for the responses.
Am I correct in understanding that Bridgeport’s series 1 & 2 were being produced during the same time periods and that the different versions of the Boss controler were being fitted to either series 1 or 2 depending on the year of productions. With what version of the Boss controller did Bridgeport change form stepper to servo motors? Would it be correct to assume that the servo motors were better?
Jeff

[jholland1]

Shift from step motor to dc servo occured with Boss 8. This was an improved operating system due to encoder feedback which reduced positioning error. It was a more complicated system and they also have usually been converted to other controls if machines are still around. Bridgeport then began using mill frame from manual series one and driving with servo system and ball screws. The hardware is inferior to the Boss series made 10 years earlier. By late 80's BP had lots of competition and cost cutting was the mandate.
jh

[wcarrothers1]

I think they were most all special orders where you could mix and match what features you wanted with your model. I'm not sure why my particular machine was fitted with what at the time was the best controller yet on a S1 frame if the S2 was better.

But either way I think I got a pretty great deal on mine and glad the previous owner purchased what was the top end controller of the day..hehe

I do need to go through it and replace the wiring to the drive motors as they are really stiff after years of sitting and use.

b

[jshank]

Hi,
I now understand that Bridgeport Series 1 & 2 frames were made specifically for cnc operations and fitted with a Boss series (i.e. 1 - 10) controller somewhat depending on the year of manufacture as well as the purchaser specifications.
What are the Bridgeport V2XT series machines?
Jeff

[machintek]

Retrofitted by Bridgeport with a PC based control series 1 standard.

George

[jshank]

Are there and advantages to the V2XT?
Jeff

[machintek]

Small footprint. Servo motors. Many advantages to the PC based control. Can DNC from a hard drive. I would recommend the second generation with the BMDC.

George

[jeep534]

I own a boss 9 R2E4 series 1 machine (about 3000 pounds) the series 2 machines were almost double that size they are huge and my machine is not small. for conversion to mach 3 the stepper (boss 8) machines are easier to convert to mach 3 running on a PC. Hillbilly on the mach forums is selling a card and instructions to plug right into the stepper machines. (he has about 150 in the field) the servo machines you pretty much have to gut and start from scratch keeping only the servo's "ask Me how I know" (quoting poppabear)

I hope this Helps
Happy Hunting
archie =) =) =)

Hi,
I now understand that Bridgeport Series 1 & 2 frames were made specifically for cnc operations and fitted with a Boss series (i.e. 1 - 10) controller somewhat depending on the year of manufacture as well as the purchaser specifications.
What are the Bridgeport V2XT series machines?
Jeff