CNC Bridgeport mill for sale

Ignoramus30438 fired this volley in news:ZMqdndUMttkXN0_SnZ2dnUVZ snipped-for-privacy@giganews.com:

Oh, IG! You'll play hell getting much more than scrap value for that unless your helper puts some _serious_ cleaning time into it.

(how much? )

Lloyd

I have not decieded, but it will not be the top price and further discount will be given to this ng. i will know when i bring it in.

i KK>

I ran one of these for quite a while. VERY rigid machine. Control was a POS. Put Mach control on and be happy. it will take some serious drivers to get the most out of this. I don't think Gecko goes that big.

I'd suggest a VFD for the spindle.

Karl

Exactly what I would do, VFD for the spindle, EMC2 or Mach3 for control, plus big ass stepper drives. Then it would be a nice mean machine, a good money maker. I make money with my Bridgeport Interact, selling certain doodads.

The control on my Bridgeport was a POS too. It (Heidenhain) was great for its time, of course, that that was 25 years ago. My control was dead when I bought my mill.

i

Ignoramus9564 fired this volley in news:Taedna9HZNLqDU7SnZ2dnUVZ snipped-for-privacy@giganews.com:

Heh! I'm running on original electronics in my R2E4! But then, the technology in that machine is what I made my first career around, so it's "comfortable".

OTOH, there are a lot of features I'd love the mill to have, and only going to EMC is going to solve that!

Lloyd

This one looks like the original control on my Bridgeport BOSS-3, stepper motors, truly needs clean three phase to run the three axes (not re-strapable for single phase). CPU is an ancient LSI-11. So plan to strip off the box on the side, and the box (not visible) on the back filled with a big three-phase transformer and Mag-Amps (saturable reactors).

Enjoy, DoN.

I love EMC and what it lets me do, the comfort and the convenience.

i

My own mill was the same way, not convertible to single phase. I ripped out the existing drives and replaced them with $35/ea AMC drives, that Karl recommended.

Servos work fine with mach3 too.. Just use a servo controller that accepts step and dir pulse inputs, like Granite devices VSD-E, for easy interface..

Kristian Ukkonen.

Looks like about a $300-350 per axis addition, plus servo. Pricy!

-- Do not let your fire go out, spark by irreplacable spark.

In the hopeless swamps of the not quite, the not yet, and the not at all, do not let the hero in your soul perish and leave only frustration for the life you deserved, but never have been able to reach.

The world you desire can be won, it exists, it is real, it is possible, it is yours. -- Ayn Rand

Kristian Ukkonen fired this volley in news:U4ZAr.6822$ snipped-for-privacy@uutiset.elisa.fi:

I was told by the guys at MachMotion.com that Mach cannot keep up with fine resolver or encoder inputs at any reasonable speeds. It must have a physical motion controller between the computer and the drives in order to handle things like threading or helical interpolation.

They represented that as a defect, and suggested that if I wanted to do software gearing for threading ops, I should explore either EMC, or a very expensive motion controller (that they would sell to me, but didn't recommend, because of the cost of the lathe I wanted to convert).

LLoyd

It is like saying, you can still walk with crutches if there kis nothing wrong with your legs.

i

Pardon my English, but I didn't catch if that was a negative or positive comment. I presume negative.

As far as I understand the problems with steppers are:

- lose torque at high RPM

- misses steps

The servo amp with step/dir input solves these.

The torque remains high at high RPM like any servo motor. The missed steps are not possible because the step/dir only inputs to the servoamp position counter, so the actual motor is still a closed-loop servo which can't "miss steps" as the position feedback comes from a physical encoder.

There is also electronic gear in the servoamp, so it is possible to have one input step to mean 0.01 or 100 or whatever encoder steps. I use this with 100:1 electronic gear in CNC mill spindle drive with MACH3 using step/dir signal to servo amp.. Works ok with PC parallel port.

Of course, mach3 is not equivalent to some Fancy CNC control from Siemens, Fanuc etc. but the cost is also significantly less. The step/dir input servodrive makes it possible to interface Mach3 to existing servomotors/ encoders.

Kristian Ukkonen.

Servos are not cheap. However, there is the double-axis model where one of those serveamps runs two motors, halving the price per motor.

?q=vsde-dualdc-servoI'm just a happy customer.

The main point was that if you have an existing CNC device with servos and you wish to modernize it, one quite good option (for amateurs) is Mach3 with a servo-amplifier having step/dir input for direct interfacing to parallel port.

I just did that with Emco VMC100. The axis are actually 5-phase steppers, and the spindle is servo-motor. I used Granite-devices VSDEPI board to interface PC to the servoamp VSD-E and three stepper drivers (vexta 2.8A drives). Those stepper drives I got used from ebay, the granite stuff I had to buy new. Also I got a cheap chinese modbus pendant for it. So far, I have been happy.

Kristian Ukkonen.

That's why I'll be using steppers.

Cool!

Yes, good point.

Great. I hope to have my CNC router up and running by mid July. I'm slowly but surely getting my shop cleared out enough to finish it, but I've had ten years to stuff it, so it's slow going.

Here's the metal portion of it so far:

I clear the shop enough, I'll strip it, paint it, finish a few clearance mods on the gantry, and start to test.

-- Doctors prescribe medicine of which they know little, to cure diseases of which they know less, in human beings of which they know nothing.

--Francois-Marie Arouet Voltaire, about 250 years ago

Looks awesome!

I will have some router heads for sale. They might be too big for this one, though.

i

Kind of negative. I meant to say that servos have some inherent advantages over steppers, the biggest of which is the ability to close the control loop in software, using encoder feedback.

This is why the world has moved on, and most everyone is using servo technology right now.

Right. This is a servo drive with a closed loop, and easy computer interface that looks like a stepper, so you cna use Mach3.

But what the computer does not know is what is the current following error, so it cannot make decisions involving following error over several dimensions.

What is this electronic gear, is that for threading?

EMC is pretty fancy also.

i

It is just possible to match the pulse output capability of the controller and the servodrive.

At my spindle, I would need 3000RPM * 2000ppr / 60 min/s = 100kHz pulse rate at step input to get full speed. With 100:1 electronic gear, I get the same speed with 1kHz pulse rate, which is realistic with PC parallel port.

Of course, the spindle angular accuracy is also just

2000/100=20 pulses per revolution. Works for me as I just need the spindle servo control for running tool changer (which is a EMCO hack where tool changer carousel runs with spindle servo motor through a gear touching spindle gear only in tool change position of Z, outside normal Z range).

This kind of little machine (google image found this link, not mine)

replaced the right electronics unit with a little box of modern electronics, bolted to the side of the main unit.

Kristian Ukkonen.

Very nice. You can make small stuff with it, like jewelry or whatnot. Looks very practical and sophisticated.

Here's my mill

i