My first dilema with the conversion seems to be locating a precision ball screw assembly for the X and Y axis.
I have seen that companies like Hiwin and Rockford Ball Screw have retrofit kits for Bridgeport type Series I and II mills. None of them seem to have a standard ball screw assembly that will fit my 10 x 54 table / travel size.
I have contacted Nook and Thompson, with little hope. They both told me that they do not have a standard assembly that I can use. They could make a custom assembly to my liking, but I fear that this would be very cost prohibative. Neither of them would give me a "ballpark" as to what the cost would be.
Can anyone direct me to a source for the ball screws that would fit this mill. I also need to know if I need to replace or convert anything else, such as ball / thrust bearings. Will I need to replace the yoke, or the
"cross-piece" that the ball nuts will be mounted to? I see that Hiwin has a yoke as part of their (smaller) retrofit kits.
I would like to make this machine as highly accurate and repeatable as possible. Would I need to get a precision ground ball screw assembly (+/- .0005" per foot)?
Could I instead go with the rolled (+/- .003 per foot) or precision rolled (+/-.001 per foot) ball screw assembly, and use the backlash compensation feature in Mach 3 to negate any unwanted tolerance stack up? Would this have a negative impact on climb milling performance / finish or limit table speed / feed drastically?
Thanks for your feedback.
Here are some (before) pics of the mill: