Bridgeport Manual to CNC conversion...

[Muzzer]

I was looking at those machines too ;) theres some good stuff on there at present.

The worst part with a BP conversion is the Z axis/quill drive - it has to be canted out in front of the quill and all the force must go through a single bolt into the quill - that bolt was never made to take anything more than a quill-stop :)

As the screw is driving the quill from one side there is a lot of axial twist moment on the screw which is not good.....

That's why I fitted a 1604 ballscrew on mine where the old quill stop / feed trip rod went. That reduces the overhang by a factor of 2 or so. Also makes for a more compact installation. Having said that, there are many professional installations that seem to last, as long as the bolt doesn't work loose.

There's an Ozzie guy who did the same thing as me although his is sort of upside down compared to mine. Worked out nicely. This vid shows the way he did it:

https://youtube.com/watch?v=RsUnoXgF...Nr5wQ&index=21

https://youtube.com/watch?v=4CXcWXZj...Nr5wQ&index=19

When you change your leadscrews over to ballscrews on a BP you get to realise how much spring there is in the yoke (in the saddle, holds the leadscrew nuts) and bearing brackets, even if you were to eliminate the backlash. Puts all the bollocks willy waving about "holding tenths" into perspective. In comparison, my Shiz is rock solid.