Yesterday I ran a big job on the CNC Bridgeport, where I had to move the knee a few times to accommodate the tool offsets. I messed up the job 6 times before I figured out I was running into issues with the knee wear. If I run the knee up and down the length of the quill , or about 4.5", it shifts the position of the work in the "Y" plain by .020". Tightening the gimball makes moving the knee harder, but does not affect the .02" slop. To the best of my checks, the table remains square with the quill, so only the "Y" moves.
My question is...is this normal wear, or is the knee always sloppy on bridgeports? Everything else on the machine is within .001" over the range of travel. It seems strange the knee, of all things, would be worn so much more than the rest of the mill.
I can account for it by planning tools with offsets within the quill range...just curious if moving the knee during a job is not recommended?
My question is...is this normal wear, or is the knee always sloppy on bridgeports? Everything else on the machine is within .001" over the range of travel. It seems strange the knee, of all things, would be worn so much more than the rest of the mill.
I can account for it by planning tools with offsets within the quill range...just curious if moving the knee during a job is not recommended?