I recently got a BP Series 1 1.5hp vary-speed. This is my first mill and I'm a newbe. Previous owner had started a head rebuild. I finished the rebuild with a full bearing & belt replacement. (head rebuild kit from H&W). New sealed spindle bearings, new bushing and all that. The motor and vary-disk shafts were in good tolerances. Took a big risk buying a machine torn down. It looked good, the ways and table and all visibly looked in really good condition. To my uneducated eye it looked lightly used. Not so sure now.
The problem I've run into is the spindle up/down movement seems to have a very distinct spot in rotation where it binds or rubs. Can feel this by trying to lower the quill while the mill is turning. It is a distinct "catch" or "pulsing" (depending on how fast the mill is running) as you lower the quill. I can also turn the spindle by hand and find a spot where raising and lowering the quill is distinctly feels harder like it's rubbing where elsewhere in the rotation it is more free. At higher speeds it's like a strong vibration as you raise and lower the quill. Also quite a loud noise.
I'm wondering if the spindle shaft is actually bent and rubbing somehow in the bull gear shaft. My next step is to pull the spindle and see if I can tell if it is bent somehow. Maybe chuck it up in my lathe between centers and see if I can measure any bend with an indicator.
Is this binding like this a common thing and could it be caused by anything else? I can't really think of anything else that could cause this other than a bent spindle. Obviously that's going to be a pretty expensive fix if it is so I thought I'd ask if there were any other thoughts.
The problem I've run into is the spindle up/down movement seems to have a very distinct spot in rotation where it binds or rubs. Can feel this by trying to lower the quill while the mill is turning. It is a distinct "catch" or "pulsing" (depending on how fast the mill is running) as you lower the quill. I can also turn the spindle by hand and find a spot where raising and lowering the quill is distinctly feels harder like it's rubbing where elsewhere in the rotation it is more free. At higher speeds it's like a strong vibration as you raise and lower the quill. Also quite a loud noise.
I'm wondering if the spindle shaft is actually bent and rubbing somehow in the bull gear shaft. My next step is to pull the spindle and see if I can tell if it is bent somehow. Maybe chuck it up in my lathe between centers and see if I can measure any bend with an indicator.
Is this binding like this a common thing and could it be caused by anything else? I can't really think of anything else that could cause this other than a bent spindle. Obviously that's going to be a pretty expensive fix if it is so I thought I'd ask if there were any other thoughts.