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1997 Bridgeport help! My y-axis is binding at times?

mechatgsk

Aluminum
Joined
Feb 23, 2006
Location
Wilson, NC
Hello, I have a 1997 bridgeport series 1 mill and at times when I am edge milling using the y-axis I can feel a binding spot. It is more noticeable when I move the y-axis toward the rear. I feel the nut or screw could have a problem. I bought this mill on ebay and the chrome knee ways look very good. They still show good frosting or flaking, even in the middle of the knee where most of the movement has occured. I replaced the manual bijur hand pump and all orfices with new parts when I got the machine. Machine is oiling good. Can anyone give me some advice on this issue?

Thanks,
Mechatgsk
 
Hello jkruger,
Are you talking about the heavy metal covers on top of the knee that slide with the saddle movement?

Mechatgsk
 
Check your Y axis gib.

Does it fit properly in adjusting screw??

Is a part of the gib broken??

As stated before, the chip cover (it is just one piece) can get dinged, burred, hang up on crud...
 
If the sliding covers are not the issue, It sound like the feed screw nuts might be loose. Move the saddle (Y) out towards you as far as you can go and lock the lock screw or place a wood block behind it and the column and remove the 4 aleen cap screws holding the feed screw bracket to the front of the the knee. No need to remove handle or dial..so leave that alone.

With the 4 bolts removed crank the handle and the feed screw unit will come out toward you. When it is out, look in the hole and check the flat head bolt (aprx) 7/8 dia. head that holds the 2 brass nuts in the bracket. I suspect the screw is loose. It has 2 brass nuts in the bracket hole and they work as a backlash eliminator. If that's OK I check the feed shaft dial and see if it and the bearings retainer ring is tight (the one you just puled out) sometimes they get loose and lets the feed dial drag on the bracket.

One more thing would be the gib, bit usually when they are loose the bind up when feeding out as they go deeper into the taper. The gib screw and knotch in the gib may be loose allowing the gib to move up and down and and bind up kitty wom-puss. One more thing when you re-install the feed screw be careful not to cross thread the screw when starting into the brass nut. If it has roll pins in it, you may want to remove them or tp them back so only a little is exposed on the inside of the bracket. Trying to get them aligned when they are sticking out all the way might end them when screw the screw back in. Good luck and if you need more info please PM me. I am a rebuilder and have rebuild hundreds of Bridgeport's over the years. Good hunting :-)
 
Thank you all for the replies. When I get back to the shop hopefully on the weekend I will check the things you guys have informed me about. I do have another Bridgeport series 1 (1982) taken apart for a rebuild. I can look at the things you guys are talking about, hopefully understand it better. Then dive in and gitter done.

Mechatgsk
 








 
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