Stuck bridgeport knee

Hey folks I picked up an old bridgeport the other day for a good price because the knee is stuck. I took the table off and did a little looking around, it turns out the the knee nut had twisted off the pedestal causing the knee crank to free spin. The previous owner try so hard to crank the knee after it had stuck they broke off the very top portion of the pedestal, that's not my major concern at this point. My big problem is breaking free the knee. The knee gib adjusting screw is missing and it looks like the top portion of the gibe is missing so I can't adjust the gib.

I've tried to jack up the knee to loosing it and I've tried downward pressure as well. I've got liquid wrench on all the parts and ways hoping it will soak in and loosing up the components. If anyone has any suggestions I'd be grateful for the help.

Thanks

Reply to
jfisher
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I'll bet the answer to your problem will be loosening the gib and getting it out. There may be two gib adjusting screws, one on the big side, and one on the small side. If so, take the one on the big side out, put it into the small side, and push it out. If there are no screws on either side you need to use a hammer and a drift punch an knock the gib out from the small side.

Reply to
Polymer Man

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Reply to
~Roy

If my memory is clear on this, and I can't check because my present mill has square ways, the large end of the gib is at the top of the knee such that if the adjusting screw is gone and you crank the table up the gib tends to wedge itself. The obvious solution is to lower the table and hope the gib frees up - a more desperate and awkward move is to hammer on the bottom of the gib with a brass drift to try to break it free.

You should also be aware that there's a stop screw in the column between the dovetails that limits the knee's upward travel, but the missing adjusting screw points to the gib as the problem.

Ned Simmons

Reply to
Ned Simmons

I agree that no matter what the problem, loosening the gib is a first step. But, most Bridgeport knee gibs have screws 'keyed' to the gib. So, the gib has a groove, and a groove and ring at the end of the screws engage the "hook" at the ends of the gib. So, you can't get either screw to come out by itself. You have to get the screws loose, and then work them out together with the gib. If the gib is truly frozen, then you risk breaking off the screw that you are trying to pull with. The gib has to come UP to loosen.

Jon

Reply to
Jon Elson

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