[h8ers_suck]

I am very new to CNC and just purchased a BOSS 5 that the previous owner hooked up a hillbilly bob interface board and used Mach 3 software. He used all existing components to run the machine. I am looking to lower the footprint of the machine (eliminate the 2 huge boxes mounted to it so it will fit in my garage better) and update it.

I have been able to find tons of options for break out boards this one in particular seems to have a few more functions Campbell Designs - CNC with Bob Campbell. Can anyone recommend one that will be easy to integrate with my machine?

I am also looking to eliminate the loud 3 phase converter; can anyone recommend a way anything?

At the same time I will likely upgrade the stepper motors. Does this machine have NEMA 34 or 42 steppers? What would you recommend I purchase to replace them with?

Any help would be greatly appreciated.

Thanks,
David

[Wade]

I have a older Boss with a 2HP head, 3 Phase motor. Pulled out all the circuit breakers, and magnetic controls, and replaced everything with a 2HP electronic VFD.

I just wanted to use 220VAC house power, 2HP, variable frequency, and simple to reverse the motor. There's lots of options, if you want to control RPM from the G-Code. But, a very basic unit like this one will do it.

2 Hp VFD Phase Converter

The cabinet looks like a ghost town now. All that stuff, replaced with this little cheap plastic box. You don't need an expensive unit to run a mill at home.

Depending on your control system, you will probably need a simple relay card, to interface between the Controller, and the new VFD.

I used this Relay Board: TTL Logic Level Inputs, 2 SPDT 15A Relays - Winford Engineering

With an external wall wart.

You need to know how much current your controller can supply, and at what voltage it supplies it at. Mine puts out 5 Volts DC or 0 Volts DC, at a max of 10mA. This board only need 2mA, so it will work with my controller.

[polaraligned]

The existing steppers are NEMA 42. I like servos as a replacement, but of course they cost a bit more. Someone does sell some economical servos (maybe keller) that others have used with good success.

[h8ers_suck]

I have a bridgeport boss with 1:1 drive pulleys; would it require a gear reduction to run servos? I have found where people are getting the pulleys; however, I am not too sure how they are making them work. The Y axis is an 18 tooth pulley and to reduce that to 2:1 I would need a 9 tooth pulley on the servo or a 36 tooth pulley on the screw; is that right? I can't find anyplace that sells a 9 tooth pulley and I am only guessing but I don't believe a 36 tooth pulley is going to fit in the in the case. How hard will it be to replace the pulleys on the screw for this machine? What is the preferred method to reducing?

[mactec54]

h8ers_suck

No reduction is needed if you have the right servo motors, you should stay with the 1:1, 750W motors is all you need, look at the Dmm Tec they are about the easiest to install/setup

[polaraligned]

Plenty of machines have been retrofitted with 28 in-lb DC servos and 1:1 pulleys.
The price of china made AC servos is so cheap now, you may want to go with them.

[mactec54]

polaraligned
Plenty of machines have been retrofitted with 28 in-lb DC servos and 1:1 pulleys.

Yes with pathethic performance, 40 in-lbs is about the minimum you can get by with

[polaraligned]

My Series 1 machine runs 12.5in-lb baldor servo's @2:1 which puts less torque to the ballscrews than the 28 in-lb servo and a 1:1 ratio.
My machine will run 60-70 ipm rapids (limited by the Gecko drives faulting) which is plenty for a 12" x 18" work area and will EASILY snap a 1/2" endmill in half.
How much more torque do you need? I have taken deep cuts with a 1/2" endmill into steel and had the spindle motor stall without the the table feed hesitating.

[mactec54]

polaraligned

The standard Bridgeport Boss 5 ran at 130 IPM Rapids, so you are only running around half the speed of what the old stepper motors would do, In testing I have run them up to 750 IPM to see how well they could do, I set most at 450 IPM for rapids, 60-70 IPM is cutting speeds

[polaraligned]

As I said, it is because of the Gecko's following error faulting, not because the motors are underpowered. I have not wasted my time better shielding the encoder cables and changing the encoders to improve my rapids. At 70 IPM I spend more time cutting than rapiding with smart toolpaths. Point is that 25 in-lb is plenty at the ballscrew and the motors are not underpowered. I have a Centroid running 28 in-lb servos on a Series 2 and it does 150 IPM rapids. Faster is not worthwhile on these machines. You are not saving any time after you factor in the time you waste changing tools on a job. If you need real VMC performance to bang parts out, then get one.

[mactec54]

Polaraligned
If you need real VMC performance to bang parts out, then get one
Faster is not worthwhile on these machines

There would be not point in rebuilding these machines unless you can build it better than what they were, faster is always worthwhile

I have a number of VMC machines, The Bridgeport I have is only used now for secondary operations & long parts that won't fit in the VMC machines enclosures, the rapid/cutting speed is great, Plus with the rigid tapping, it runs the same but smoother than Haas machines we have

[tereroche4]

And practice before you put the actual chip on.