Bridgeport Series II CNC milling machine

i am thinking of getting a Bridgeport Series II CNC milling machine which is currently running with a 286pc serial cable and bobcad cam produced files via a floppy. still under power but has not been used in 5 years. i am looking to use it for 2nd ops.
a few questions:
1 - to see if my cam supports it what is the controller for this machine?
2 - what is this machine worth?
3 - how difficult to retrofit with linux cnc? thanks!

Are you sure that is a series II ? I thought they had #40 taper spindles with a bigger quill.

Stepper motors? Stay away unless you convert to servos. Money and time pit!

Ed.

That is what the seller is saying. I have never dealt with a Bridgeport before only a Tormach cnc mill.


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atex57 said:

Are you sure that is a series II ? I thought they had #40 taper spindles with a bigger quill.

Stepper motors? Stay away unless you convert to servos. Money and time pit!

Ed.

Click to expand...

It appears to be a "Series II Special", the base, knee and table of a Series II, fitted with the 2HP head used on the Series I.

Might be a good candidate for a control retrofit, but unless you want to make it a hobby, likely $15k from Centroid. Otherwise, definately a money pit.

Dennis

Thanks for the replies. You are correct I do believe it’s a series 2 special. What attracted me to it was that it’s already cnc and can be fed via rs232 serial to a pc bypassing the stock controller.


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If you are looking for a production machine I would look elsewhere, time invested converting this is production money paying already working machine.

Marko

cncbuilt said:

Thanks for the replies. You are correct I do believe it’s a series 2 special. What attracted me to it was that it’s already cnc and can be fed via rs232 serial to a pc bypassing the stock controller.

Click to expand...

You might be able to "feed it via rs232 serial," but you would still be relying on the ancient stepper motor driver boards, which I understand are problematic on old Bridgeport machines.

Dennis

Modelman said:

You might be able to "feed it via rs232 serial," but you would still be relying on the ancient stepper motor driver boards, which I understand are problematic on old Bridgeport machines.

Dennis

Click to expand...

Thanks guys for the tips. He went down to $1500. It I think I will pass on it. I don’t want to end up with a basket case to deal with.


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I have had a 1981Boss 6 Series II machine since 1985 that is still running with it's original controls and pretty much everything else original. It is rock solid as machines go. I run it daily. Connecting it to a computer, only means someone worked out the 4-wire connection to DB-25 transition so it could be connected to a serial port. I did that to mine many years ago so I could get rid of the teletype, then used various "dumb" terminals to interface with the machine until I got into EZ-CAM programming software. So much easier to create a program and post process it than to type the whole thing into the machine memory. My take on this setup is the owner uses something like EZCAM or BOB-CAD and post processes the machine file to suit the BOSS 6. While this is pretty standard practice with these "non-conversational" machines, it seems very old-timey to some. Most Cad-Cam programs don't necessarily come with the post processing file to do justice to the BOSS 6, but they are available. For the $1500 price, I would jump at the chance myself, especially if it came with the programming computer itself. If the owner is running EZCAM, up to Version 6 or so will run on almost anything - I used a 286 with Windows 3.11 for Workgroups until a few years ago, then went to Windows 98, now running the same program under xp. Doesn't do 3d, but 2-1/2D is fine for me. BTW Spindle taper is NMTB 30 or Erickson QC-30, which is pretty much identical. As far as the stepper motors go, they were so over built, I have never had one fail, and I have had a BOSS5 since 1981. The top rapid travel for the BOSS 6 was 100 IPS, and you could program that as a feed if you dared. The Boss5 was 30 ips top programmable feed, with 50ips rapid, I think. The spindle on the BOSS6 is larger diameter than the BOSS5, but most of the top end is almost identical to a BOSS5. My machine had an air-pressure assisted table elevating screw, which is about the only thing that no longer works.

I own one Bridgeport Series II CNC and two Bridgeport Series I CNC machines. All three have BOSS 6 controls and all three are running under all original equipment with a windows 7 notebook attached via RS232 for programming. These machines are built like brick sh*t houses and are every bit worth the $1,500 the seller was asking for the one mentioned above and I wouldn't hesitate purchasing it if it were in my general vicinity (mid west).

It should be noted that these units use the Erickson Quick Change 30 spindle which is NOT compatible with nmtb30. There is a slight variation between the two that prevents tool holders of one from being used with the other.

I see a lot of people bash these machines however I have to believe they have never been exposed to one. They are heavy duty work horses. It is possible to retrofit these machines with a simple breakout board and control them via LinuxCNC or Mach3/4 without changing out the existing drivers and steppers which we intend to do. Fact of the matter is we haven't yet because it is not the challenge everyone wants to suggest programming these machines if you do so through modern software and load the resulting G code through the RS232. Works like a champ for us and is quite painless.

Fredhh47, I would love to stay in touch with you as it is always worth while to have working relationships with others that have the same vintage equipment. If you would like to do this please let me know and we'll pass private information for communications.