Knee not running true on Bridgeport

[danpatch]

When i raise and lower the knee to drill and ream a hole the reamer is not centered. I tightened the gib on the knee . Got coupe of turns on the adjustment.Could this have been my problem .

 

[Ulma Doctor]

If you were so inclined, you could mount a DTI to the table and then indicate the vertical ways, the readings will tell you how far out you may be.

 

[T Bredehoft]

Does the reamer line up after the adjustment? if so You're god to go.

 

[john.oliver35]

You will see this same effect if the head is not correctly trammed. Because the table is at different heights for drilling and reaming, the end of the cutter will be offset.

 

[projectnut]

Which way is it not centered, in the X direction or the Y direction? I'm guessing if it's in the Y direction the nod on the head is the problem. The first thing I would do is tram the head to the table. There are dozens of YouTube videos showing how it's done. The hardest part is going to be adjusting the nod. Often times on older machines the bolts holding the gear in the head become lose allowing the gear itself to move slightly without having any effect on the head. If that happens it will be difficult at best to get the head properly positioned every time you tighten down the head, it can potentially move.

 

[danpatch]

It is ways the X axis that is off. I think mounting a dail indiator on the would tel we what is going on . Thanks for the help

 

[Janderso]

When i raise and lower the knee to drill and ream a hole the reamer is not centered. I tightened the gib on the knee . Got coupe of turns on the adjustment.Could this have been my problem .

Sounds like you may need to tighten the gibs on the knee.

 

[mmcmdl]

Tram the head . Check first by raising the table without moving your spindle down . Either way , you indicate your part with machine set-up for operations . ( the table should be raised and indicated again ) .

 

[MyLilMule]

Sounds more like the head is out of tram.

 

[ttabbal]

When I had a similar problem, I had to tighten the knee gib. I found that moving it up and down between adjustments helped make it easier to tell when it was right. It initially felt good, till I moved the knee.

That and the head tram are probably the most important things to adjust for something like this.