BRIDGEPORT TABLE BIND

Currahee26

Currahee26

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Apr 14, 2017
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Greetings,
I have a BP round ram knee mill. (M head) In pretty good shape actually, that i got for $500. I had to replace drawbar, some felt wipers and the spindle oiler wick. It had been lubricated with GREASE it nearly all its fittings so the cleaning process took a long time.
Now, the table works well from right to left, (starting full right and moving left) BUT when it gets half way in this travel the table binds so tightly it takes two hands to turn the cranks. Anyone have an idea why this is happening?
1. Will a two piece cross feed nut solve this? ( If so, can I just cut the current single piece nut in two?)
2. The gib had a very thin piece of tin spot welded to it when I took table apart to clean and OIL. (like some sort of a shim)
3. Can new table gibs be purchased?
Anyway, I'd like to get this fixed so I can use the whole table. I have a BP vice bolted down in the middle but have to move it for bigger projects!

Thanks all info and comments in advance.

Dave SO FLA
 
a picture or two would be helpfull. I suspect the shim is the issue. test it by leaving the gib out and see what happens. You may have to push the table back. Usually the tables bind on the ends, so it's odd. show us some pictures.
 
Agree with Rich, should be just the opposite; loose in the middle
M
ps could your table actually be bent?
 
Your problem sounds like a bit of an oddity. I would give these people a call to help you diagnose the problem. They have been rebuilding Bridgeports for many years. If anyone has run across this problem it has to be them.

www.machinerypartsdepot.com

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As for splitting the nut it is certainly doable. In fact Bridgeport recommends it to lengthen the life of the original split nuts. I did it on my J series machine. New gibs are also available, but the first course of action should be to call H&W to get a better understanding of what your problem may be.
 
If it is OK right to left, but not OK left to right then that normally means that the gib is not held tight and can float back and forth. Normally there are screws on both ends of the gib, they need to be tightened against each other to keep the gib in place.
 
It's hard to tell from the prints, but if it's like the J head machines the head of the adjustment screw overlaps the edge of the gib. The thicker end of the gib and the adjustment screw are on the left end of the table As the screw is tightened the gib moves to the right and wedges itself between the table and the way on the knee.

If the table, gib, or ways are badly worn the gib may float as Jim suggests. If that happens it will be loose moving in one direction and bind when moving in the other.
 
JimDawson said:
If it is OK right to left, but not OK left to right then that normally means that the gib is not held tight and can float back and forth. Normally there are screws on both ends of the gib, they need to be tightened against each other to keep the gib in place.
Click to expand...

Jim makes a good point, but the gib on a Bridgeport is small on the right end and if he is cranking to the left and it gets stuck in the middle ( if he is standing in front of the mill that is) OP said
"
Now, the table works well from right to left, (starting full right and moving left) BUT when it gets half way in this travel the table binds so tightly it takes two hands to turn the cranks."
So the gib moving out to the left the gib would get loose not tight on the taper. He needs to pull it out and test the machine like I said before. Photos would help too. I have also been rebuilding Bridgeport's for over 40 years nuts and I am free. I am trying to trouble shoot what's wrong. It does sound like the spot welded gib is the issue. That's a really old machine. They started making round arms in 1938. You would be smart to take the whole table off, clean the crud and show us some photo's/ I always tell folk to buy parts from H&W too, but lets help here so all can learn the problem. The guy who screwed up the gib may have been a crappy rebuilder and screwed up the table and no matter what we do to the gib it will still be screwed up. Until we see the machine apart and tell the guy how to check the table we won't be able to help him correctly and continue to guess.

Hopefully you have the lock loose?
 
Last edited:
ok! Thanks everyone for all the great replies! Heres what has happened to so far; I completely removed the (original-numbers matching) gib. As I was moving the table from left to right, (i may have misled everyone previously.....table is FAR LEFT as you look at it,to start. Cranking it to the RIGHT is good only half way...then starts the bind) it got more and more easy to turn as I backed the gib out. BUT! Once the gib was completely removed, it was still bound up in the last 12 inches of travel. I could move it, but took considerable effort. Notice the groove in the gib? That may have been put there by the lock? (If I moved it while the lock was engaged?) The spot welded shim I have referred to has been removed by me some time ago as one weld had come loose and I didnt know what I was doing! So I pulled it off. The spots are not raised and are very smooth. One spot is visible just below the stamped serial number in the third pic. Did I by chance, install the cross feed nut BACKWARDS? I can take the table off in a week or so, as machine is being moved north 30 miles to a new shop and check things out. THANK YOU ALL for your time and comments. dave SOFL (So sorry if I confused anyone in my description...I'm retired from the US Government!!)
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