bridgeport series 1 cnc help

[pyroboby]

Hi all,
First post here, so bear with me. I bought the above mentioned machine for less than a 1000 dollars, only problem the shop had was the y axis quit working. Instead of replacing the board for the y axis i would like to retrofit it to run on a pc. I would like to keep the original stepper motors.

I am eyeing mach3 as control software but after that, im lost on what i need. Any help would be appreciated. Thanks

Rob

[ETChipotle]

What kind of bridgeport series 1 CNC do you have? Is it one of those cool BOSS machines? All the smart folks on here will want to know what model so they can make recommendations.

Congratulations and have fun!!!

[pyroboby]

Yes, its one of the boss ones. Dont know which but from what ive read, it doesnt matter if you plan to retrofit the machine. It has a rigid ram head on it.

[John Bennett]

If it has smooth round motors it is a Boss 8 and up with servos, if it has wavy heat sinks it is a Boss 6 and down.

[pyroboby]

Yes, it has stepper motors. I'm looking at doing the Ajax retrofit that uses mach3. I'll to dig into it Monday when it gets delivered. I can't wait!

[pyroboby]

Ok guys, I've had the machine and it is a BOSS 4 5 or 6 control. It has the original stepper motors. What do I need to get this up and running with new controls. As stated earlier in the thread, I would like to use mach 3 with a pc.

I will admit I really dont know anything about wiring on this machine as it did not come with a book. Is it plausible to keep the original steppers and retrofit. I dont think my original plan to use an ajax kit will work as it says the drives are for servos. While I'm sure this stuff isnt complicated, it seems so from my eyes at the moment. Hopefully you all can give me some wisdom and direction. Thanks again.

[HawkJET]

Originally Posted by pyroboby Is it plausible to keep the original steppers and retrofit.

Yes! I have done just that, as have many.

You will need a PC and Mach3, a BreakOut Board (BOB), and stepper motor drivers. I used my own design BOB but there are several that are suitable. My stepper drives are Compumotor ZETA drives, but the most popular seem to be Gecko. With Geckos, you will also need a power supply.

When I started my retrofit, I removed all the electronics and cabinets. The only things I kept were the steppers and limit switches.

It would be great to see a picture of your machine!

[keebler303]

I have a BOSS 5. I am running it on mach3 with the original steppers and drives. I am using the "Hillbilly" BOB. He is a member here.

Your Y axis problem is most likely an easily replaced transistor. Search here and you will find lots of discussion on the transistors. Factory one was a 2n6547 I believe.

I have a couple threads here with ome details about the conversion to mach, you can search for those too.

These are really nice machines, you'll be happy once its up and running.
Matt

[Alxw]

Hi I'm also new to CNCzone.

Just wondering why one would replace the drives when keeping the stepper motors? Is there an obvious reason for this?

It seems like an extra expense if theoriginals could be used or am I missing something? (probably!)

I have my eye on one of these machines (Boss 4/5/6) but want to have a plan in place to retrofit it.

[HawkJET]

Originally Posted by Alxw Just wondering why one would replace the drives when keeping the stepper motors?

The power transistors in the old drives are the weakest link in the entire machine. They were manufactured in the late 70s and 80s. The technology was nowhere near what it is now. Today's drivers can easily handle more voltage and current and are exponentially more reliable. Also, back in those days, there was no such thing as microstepping. The advantages of microstepping are huge and transform the speed and smoothness of the machine.

Replacing the motors is a royal pain. They were specially made for Bridgeport and are physically different than standard steppers available today. The Bridgeport motors have an extra long shaft and is 5/8" diameter with a keyway. Also, today's motors have so much more torque, you don't need to get as large a motor. This contributes to the physical differences.

Making an adapter to use a 34 stepper instead of the 42 is not difficult, but it requires the motor face to be displaced from the stock location. The motor shaft is is already too short and only 1/2" diameter (rather than 5/8"), so this setback exacerbates the problem. There is a moderate bending load on the motor shaft from the belt tension. This can be problematic when extending the shaft.

[pyroboby]

What are your thoughts on this kit here

3-Axis NEMA34 1125oz in 72V/20A PSU G320X Gecko Driver | | Automation Technology Inc Automation Technology Inc

How difficult would getting these to fit on my machine be? How do these compare to the original steppers on the bridgeport.

[keebler303]

Originally Posted by pyroboby How difficult would getting these to fit on my machine be? How do these compare to the original steppers on the bridgeport.

Everything Hawkjet said is true. You would have to machine adapter plates for the motor mounts. You would have to machine shaft adapters for the motor shafts. Servo motors deliver more power at higher speeds, which means you would need a belt reduction setup IF you wanted to use the full capability of the motor. If you mount them direct your motor will never see more than a few hundred RPM. It will put out the most power at 2-3000 RPM.

Reusing the steppers will save alot of headache. Plus you can use the machine to make the parts for a future upgrade if you want to later on.

Matt