I have had my Bridgeport Series I mill for about a year and a half now. This is my first CNC mill and I am at the point where I think I finally have it all figured out and have been making some nice parts for friends. With the exception of some backlash and runout issues I am pleased with this machine.
I contacted a local Bridgeport service tech to give it a once over about 6 months ago and he showed me how to adjust the backlash and since then I am seeing improvements in my parts (squares are now square and holes are circles). But I am not happy with the spindle runout I have and the poor finish it leaves. The tech said my runout was within tolerance (if there is any such thing) but I am not happy about it. I am seriously thinking about getting some new bearings installed on the spindle and having the spindle taper reground while it is mounted in the machine. I hve found a place that will regrind the taper at their shop, but you need to remove the quill assembly and ship it to them also - I would rather not have to disassemble part of the machine to have the spindle reground. I have read a few threads on the topic but am not sure I correctly understand what bearings I need (and the best place to get them from) and where to see about getting the spindle reground. I have found a few places but haven't checked yet to see if they will travel (I am currently in Southern California but will be moving to Idaho in a month).
Also, I am having a hard time identifying the model head on the machine - I have had several people tell me different model designations. The machine is a Series I Rigid Ram with the 2HP motor Boss 3 (replaced with Centroid controls). Serial number on the knee is CNC 4331 and I couldn't find any numbers on the ram or head (but the numbers 5849 and 5812 are engraved into one of the trim plates on the side of the ram). I know this machine was rebuilt with parts from a few different machines. I do have a manual dated 1978 but it really isn't much help in figuring out what the model of the head is. Any help on this would be appreciated.
About the spindle. The spindle in the machine now is the Erickson QC30 spindle without a through hole for the drawbar. But I do have an extra spindle that came with the machine that does have the hole. Would it be better to swap out the spindles so I can eventually use a drawbar or rebuild the one in the machine now? I am not looking for ultra precision, but would like to not resort to sanding every part I make. Eventually I may look at getting a full rebuild with some premium ballscrews or just step up to a newer VMC machine.
I am also thinking about getting some leveling mounts since the new shop floor is a bit out of level where I want to put this machine. What would be some good leveling pads to get for a Bridgeport?
If anyone can help me out or offer advice, I would greatly appreciate it.