Boxford 190 VMC

[Misterg]

Stepper Motor drivers are reasonably inexpensive

Beware.

The "TB6600" drivers generally work OK, but they (almost always) don't have TB6600 chips inside, and fail quickly if run at the advertised ratings.

TB6600: Fake or not? But, who cares?

Having been focused on the CNC world as both a hobbyist and electronics designer for a while now, I have been struck by the sheer amount of garbage being peddled on Amazon, eBay and Ali-whatever. One instance that has stood out to me is the TB6600 stepper drivers. These are, supposedly, built...

www.grbl.org

That seems *really* cheap for a DM542 driver - One from a reputable source:

https://www.stepperonline.co.uk/leadshine-digital-stepper-driver-0-5-4-2a-20-50vdc-for-nema-17-23-24-stepper-motor-dm542.html

Of course, the first thing is to determine what current the motors you'll be using require, and what voltage the power supply is (unless you're intending to get a new one) and then select a driver to suit, but the DM542 is a good option provided it's suitable.

Bart Dring (the author of FluidNC) tended to give short shrift to any questions relating to hardware from Aliexpress, etc. on the support discord, which may sway your choice of board.

 

[Misterg]

You could run it with GRBL to start with, then all you'd need is an Arduino plus your stepper drivers. (No tool changer though.)

 

[mikegolding]

I have a 190 VMC converted to use linuxcnc . I kept the original stepper motors and driver board driven by a new board that gave step and direction pulses and a 0-10v i think output to control the spindle drive . The stepper diver board also had a couple of voltage regulators on it ( 5 and 12v ) that were used to power the new board . My memory is a bit hazy , but if you need any more info photos etc please ask.
Mike

 

[indy4x]

@mikegolding I could well be picking your brains on your conversion

Unfortunately mine does not work in manual mode, nothing moves or spins when pressing the buttons on the front panel and I don't know why. Rather than faff about trying to fix it I'm planning on replacing everything except the stepper and spindle motors

I wasn't sure what voltage the spindle motor required so thats 1 question you've answered for me already

 

[mikegolding]

don't hold me to the 0 to 10v i will check tomorrow , the drive for the spindle on the left of the back panel on mine takes mains voltage and the control signal voltage and puts out about 200v DC if memory serves me ok to the motor through a choke on the left in the front. I cant remember the make of the spindle drive but I know info was available online about it.
Mike

 

[Screwdriver]

Pretty sure mine was doing something. Ping me if you need me to measure something...

 

[indy4x]

The Boxford CNC lathe has a 0 - 180V motor and controller

AndysMachines on YT kept the Boxford motor controller when he converted his Boxford lathe to modern electronics

 

[indy4x]

I had previously made a stand for the lathe and mill, they are both on castors so I can move them around. The lathe is on a separate stand and its like nested tables





Started stripping the covers off so I could give it a clean and see how the auto tool changer works. I knew it needed compressed air as there was a pressure regulator bolted to the side of the mill. This is the view with some of the covers removed





The carousel has a pneumatic activated pin that locks it in position for a tool to be swapped. I managed to lift the pin with a long nosed pliers but it would only turn a few degrees before 1 of the toolholder came into contact with something.

There are 5 bolts holding the carousel in place so took it out

Picture of the carousel, it holds 5 tools. Hole circled in red is where the pneumatic activated pin (no idea what the correct term is) drops in to index the carousel



Hole circled in yellow I believe is how it knows where position 1 is on the carousel, there is some sort of sensor that lines up with this hole, circled in red below



As previously mentioned, the carousel has 5 positions, there is 1 toolholder in the spindle plus 2 in the carousel so I'm missing 2. There are several listing's on eBay for S/H replacements but they are around £80 each.

The 2 missing ones were probably liberated as they could easily be removed from the carousel



They aren't specific to the mill, new are available that look like they will fit but don't have the pull stud.

Not a priority ATM, need to get the conversion done

 

[indy4x]

It lives

Had another hour on it tonight, I'd really like it to be able to manually drive everything before I start the conversion just to be sure that it works, and see how the carousel does its magic.

Put a new plug on it and started checking connections, interlocks etc and I touched or moved something and it all sprang into life

Put it in manual mode and I can drive all 3 axis and the spindle. X and Y traverse correctly, spindle does forward and reverse, Z axis will traverse downwards but not up. Suspect it might be the switch on the front panel but ran out of time to investigate further

Also need to put the carousel back together, plumb in some air and check thats working