Bridgeport Manual to CNC conversion...

[Davek0974]

Yep, it was a nice thought but had a good think over dinner and using the existing motor and VFD is the sensible option. As said, rigid tapping is not needed and using the variable mechanical drive with the VFD as well will give full spread of speed and torque from 40 to 3000rpm if using back-gear or 400 to 3000rpm in high alone. My tweaked macro will tell me where the mechanical dial needs to be so problem really.

It was a nice thought but a luxury and cash will be needed for fitting out the cabinet etc, when i find one big enough.

[Davek0974]

CSMIO, servo motors and drives arrived a minute ago, all looks very heavy-duty indeed, just ordered a DB25 break-out block for the MPG unit and one of the neat little power divider blocks from CS-Labs :)

Got the mill head stripped, paint on order, removed all the surplus gears and junk from the head.

Wondering about doing the neat Z axis fit where the ball-screw takes the place of the feed-stop screw and is a 1605 unit OR doing the more common fit where the ball-screw sits in front of the original feed-stop screw position???

The only downside I see with the first option is that the pulley sits at the bottom of the screw right in front of the spindle nose.

[komatias]

I will send you a photo of my setup later on. I have made parts to allow me to use the manual quill with the removal of a single screw.

Also look on CNCzone for SCzEngrgGroup's conversion of the bridgy.

[Davek0974]

Have motion on the test motor now :)

Needs tuning i am told but there does not seem to be a tuning option in the drive menu??

I did an auto-tune in CSMIO but that only goes so far, even the manual tells me it needs to have the drive velocity tuned in the driver before auto-tuning or it will fail.

[lucan07]

Sounds like a question for Jazz, write that you've decided to use a 6560 and he will appear

[Davek0974]

It seems the drive is pre-set when enter the motor code number so no tuning in the amp.

Have finally got the head apart on the mill - a tiny broken shaft was holding me up - an absolute bugger to get out.





Now thats off it should move a bit more rapidly. The plan is to do a complete strip, wire-brush the poor repaint job it has off then sand and repaint in "Bridgeport Grey" engine enamel and reassemble to a bare machine then fit the CNC conversion.

The DRO and Original, working power-feeds will be sold off to raise funds.

Space is the biggest problem, will probably have to erect a shelter and do most of the prep in the garden.

[Davek0974]

Thoughts over coffee - Limitations of the system?

When i was building the large scale traction engines, everything was made with a tolerance of only 0.1mm or better - easily obtainable on a hand controlled Bridgeport with a three digit DRO. It really was not needed to go tighter on these engines and many say that if too tight they never worked properly due to expansion when running etc.

Anyway, the third digit on the DRO was pointless as you could never set that precision by hand and merely looking at the mill out of the corner of your eye made it wobble more than that!

So, now (when done) I will have ball-screws and servo's with Mach3 acting as my DRO display - this is all running on my bench very nicely now.

But - the encoder/motor is connected to the screw via a toothed belt - surely this must introduce an error possibility, especially with a 100kg sitting on the bed??

My main point here is - If i want to use the mill manually, say to drill some holes without cam-ing the job, I can put Mach into reset, this drops out the servo motors and i can spin the handles like before and Mach tracks the position on screen - I am hoping here that this is a workable situation with decent accuracy when positioned manually??

[JAZZCNC]

Sounds like a question for Jazz, write that you've decided to use a 6560 and he will appear

No I won't .!! . . . . Because I already told him via Private bongo's.