[jfroux_1]

Jeff,

There are internal clearances in the BP Knee Mill that must be observed. For example, the yoke at times runs close to the Z-Axis jack screw. Therefore, material from the Y-Axis ballnut must be removed to provide adequate clearance for it to pass the jack screw.

Similar clearance issues will be found with the X-Axis ballnut. So when you look for screws and flanges, be sure to look for Bridgeport Retrofit nuts and screws. You can confirm the nuts you've selected by comparing with other nuts on the market that are known to fit and provide adequate clearance.

The best documentation on the internet will be found from Hiwin. Hiwin drawings show the cuts necessary for the flanges to pass smoothly inside the knee without interference. Use the Hiwin Yoke drawing with the X and Y drawings to see how the flanges are indexed for the necessary clearance.

These drawings are for 32mm screws, but the clearances are still the same for 25 or 32 mm screws.

I used the BP yoke and 25mm screws on my machine for a while. They worked OK, but I was unhappy with the precision. I installed a Hiwin retrofit kit last year. Very happy with it.

For the Hiwin Manuals
https://www.hiwin.com/downloads.html#manuals

For the Hiwin Yoke
https://www.hiwin.com/pdf/7l0002a3.pdf

For Hiwin Y-Axis Ballscrew
https://www.hiwin.com/pdf/a10jsia1.pdf

For Hiwin X-Axis Ballscrew
https://www.hiwin.com/pdf/a10jsga1.pdf

Thanks for your comments. It does help me.