1. Home
  2. ⏣ General Metalworking
  3. BP table question

BP table question

I have a Bridgeport brand mill, older J-head. I put a Servo 150 on the X axis and have had trouble since. My table has been binding in the X direction on occasion, and today (after not using the mill for months) I checked and the powerfeed isn't even working - the pinion and ring gear don't even mesh. I took it apart and I don't understand what I'm seeing. There are shims that go in there, and all of a sudden my shims aren't bearing between mating surfaces. The table lead screw looks like it somehow got shoved too far to the right, so there is a tapered shoulder that the shims should mate to instead of a nice square shoulder.

I really don't understand how the X lead screw is located axially. There are opposing bearings on each end which it slips through, and apparently the whole business is snugged up only by the handle nut.

Can anyone enlighten me?

Grant

Reply to
Grant Erwin
Loading thread data ...

There's a pair of bearings on the left end that are preloaded by the handle and maintain the axial position of the screw. The screw is supported, but free to move axially, by a single bearing on the right. I had problems with the Servo feed on my Supermax mill which were similar to what you're seeing. I figured out a fix by studying the installation drawings for the power feed, but as I recall, a proper Bridgeport installation shouldn't suffer from the problem I found with my machine.

If you think the screw is moving axially with the left end support assembled, there's something wrong there, and I'd dig into that end before fussing with the feed.

Reply to
Ned Simmons

It's trial and error with the ship-pack.

Reply to
Tom Gardner

The previous owner of my Excello installed the table powerfeed incorrectly by drilling and pinning the gear to the shaft about 1/4" too far to the right (IE the leadscrew is translated approximately

1/4" from where it should be). This means that the non-powerfeed handwheel has ~4 threads holding it in place, and that careful adjustment is necessary to avoid binding. When I first got the machine, I had to readjust it 2-3 times a day, every day, but now (almost 4 years out), it seems to work fine.
Reply to
woodworker88

--FWIW I took the Servo drive off of my mill a while back and it's now rusting away in the back of the truck. Been rained on a couple of times but it's cheap if anyone wants it.. Decided my '70s vintage controller was better than the '90s vintage 'replacement'. $4k down the toilet, sigh...

Reply to
steamer

The previous owner of my Excello installed the table powerfeed incorrectly by drilling and pinning the gear to the shaft about 1/4" too far to the right (IE the leadscrew is translated approximately

1/4" from where it should be). This means that the non-powerfeed handwheel has ~4 threads holding it in place, and that careful adjustment is necessary to avoid binding. When I first got the machine, I had to readjust it 2-3 times a day, every day, but now (almost 4 years out), it seems to work fine.
Reply to
woodworker88

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.