Need Help!- Bridgeport series 1 cnc???

[Siddhi69]

I have been doing a bunch of reading and studying before I posted here. I just cannot find the answers I am looking for. Mostly because I am new to CNC and bridgeport mills. Maybe I am not searching for the right questions because I do not know what to ask. So please be patient.

I have a 1978 bridgeport series 1 with a 2J head and a 2 axis hurco km-1 cnc. Everything works but the hurco does not have a controller for it. The person I got the mill from said it went bad and so he just wired in a couple of switches to move the bed manually by holding a switch one direction or the other. I have taken one of the servo motors off to get the specs for it.

Seeing how it is hard to get parts for this older cnc (controller), I am thinking about changing out the servo motors for stepper motors. I have read all about the differences between servos and steppers. I am only a hobbyist and I plan to use this machine for my custom knife/sword making hobby.

The servo motors are electro-craft. The specs are as follows:
Part #703 02 049
max terminal voltage: 45v
max continuous speed: 1400 rpm (no load)
max peak torque: 2000oz-in
max peak current 45 amps
mac continuous stall torque: 427oz-in
mac continuous current 9.6amps

So here are my questions that I hope to get help with:

1. What would be a good replacement stepper motor size for these servos I have?

2. I would like to by a 3 axis kit and cnc the z axis as well. If I by a 3 axis kit can I still use it as a 2 axis until I get the z axis installed? I am not to worried about speed. Only durability and reliability.

3. Where is a good source for finding a kit? Are the ones I see on ebay worth the money or should I only buy from a reputable dealer?

4. What frame size are the electro-craft servo motors? I have tried to figure this out, but have not been able to find a suitable answer. I measured the distance from mounting screw to mounting screw and it is 2 1/8" (center) apart. I think it might be a nema 42 but I would like to know for sure before I buy motors and have to retrofit the frame to fit.

Well I hope I have given enough information. If not please ask and I will answer this best I can.

Thanks in advance!

[Perfect Circle]

Here is a good retrofit for that Hurco.
MachineMate Inc - CNC Description
Good Luck~!

[Siddhi69]

Perfect circle- Thanks for the reply, however that is a little bit out of my price range. I would like to stay under $1000 if I can help it. Hence the reason for going to steppers.

-Barry

[Perfect Circle]

Yeah that is a little high....for the diy.
Sorry I can't be of more help I'm sure someone here has all of the answers.
Good Luck~!

[ichudov]

Servo motors are superior to stepper motors. I recommend not swapping them.

I was in your situation as I had a Bridgeport Series II Interact 2 with a non-working control.

I junked the control and made my own using EMC2. It works great, as EMC2 has native support of servo motors and analog drives.

i

[Siddhi69]

Do you happen to have any more info on how I could go about setting this up? If I can get a controller to work with my motors that would be the easiest for me. Any info would be much appreciated.

[ichudov]

my conversion is documented here:

Bridgeport Series II Interact 2 CNC Mill

[Siddhi69]

That is very interesting. I would love to tackle something like this but I am not sure there is enough information for me to pull off this upgrade. After reading you documentation it sounds pretty involved. I do not have very much linux experience. Although I use it from time to time at work my knowledge is very limited.

If I was to take a shoot at this same retrofit what would it take? From what I can tell is the following (let me know if I am on the right track):

1. PPMC drive to interface from the motors (my dart controller and the encoders I will need to get) to the pc.

2. I am guessing that I can use the current dc motor drives I have to power the motors. They are dart controllers model #253G-200C. I do not know much about them but they do power the servo motors now. So I guess they will work.

3. Then setup a pc with some flavor of linux. It looks like from the EMC2 site they us Ubuntu and have a live cd that I can load to install both Ubuntu and the EMC2 software.

So far seems pretty straight forward. I looked on John's website for the PPMC. Will I need everything from this webpage?

Analog Servo Control (PPMC) : Pico Systems


If not what particular parts will I need to complete the PPMC drive to work for 3 axis?

Thanks for the reply.

[ichudov]

You have a good summary. You will probably be able to reuse the drives and encoders, though I cannot be sure. I think that hurco motors are Electro-Craft.

No conversion like this is simple and straightforward for someone who is doing it the first time. It always involves time and effort. Out of cheap, quick, and good you can pick any two.

In the end, my conversion worked out great for me.

EMC2 runs from Ubuntu Linux.

i

[Siddhi69]

Yeah the hurco motors are electro-craft. I just today found the specs for those motors. I have been looking for a while now to find more info on them. I even called hurco and they told me they had no info on them. I even called electro-craft but they were not any help either. I found someone online that was selling the same model # as mine and they had specs for them posted. So I hope they are correct. I posted them in my first post on this thread.

As far as the PPMC drive will I need everything from that webpage to complete the interface? What are the components needed for the PPMC drive? Are there other PPMC drives available that will work as well. The price of John's pico system PPMC is kind of pricey for something that I will be attempting.

[ichudov]

You can do a conversion using other interfaces, such as Mesa cards. You can join EMC-Users mailing list and ask some questions.

Do not expect any first time conversion to be cheap, quick and good.

i

[Siddhi69]

LOL! How about cheap and good? I can deal with it taking a while.

I will join up at EMC and check it out.

Thanks for the info. I might pick your brain a little more latter if I do go this route.