Re: Bridgeport quill ball screw conversion
Originally Posted by
Muzzer
I originally made a yoke with a pinch bolt that allowed me to release the quill for manual operation. However, once the CNC system is up and running, I find there's no need for manual operation anyway. The DRO display is the best way to position the tool and the manual MPG pendant gives you that manual operation anyway. It's easy enough to move the work using the MPG in the same way as you'd use the handwheels or feed lever - that includes both milling and drilling. That's just my experience.
I also looked at the approach taken by Elrod, Southwestern Industries etc and didn't like the large overhang of the ballscrew from the quill (to clear the features on the head) or the truly massive castings they used to house the ballscrew and belt drive. Instead, I fitted a 16mm ballscrew where the feed trip screw usually lives (it fits in there without any modification required to the machine). This makes the job of mounting the servo motor a lot simpler and minimises the overhang. It sounds as if you've already coughed up for the ballscrew but it might be worth a thought.
Muzzer, I have to disagree with your views on the manual quill. I find that mine is very useful, but I did design a system that allows nearly instant switchover between manual and CNC. A lever flip and a mouse click is all it takes to change over. Even with the quill in manual I still have the DRO readout for the quill.
I did look at Elrod's system, but like you, I didn't like the big casting on the front of the head.
EDIT, that is a nice clean installation. I like it!
Jim Dawson
Sandy, Oregon, USA