Bridgeport Y Axis Lead Screw Nut Tight in Middle
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    Default Bridgeport Y Axis Lead Screw Nut Tight in Middle

    I am in the process of fixing and cleaning my bridgeport round ram. The x axis works as it should although worn. How ever the Y axis is extremely tight. I had originally thought this was because the feed nut assembly was damaged and they had tightened the feed nut retaining screw too much. However with everything disassembled the nut runs freely on the ends of the screw and is very tight in the middle of travel maybe 3-4 inches. Not sure if i need just a new nut or an entire lead screw. Ideas?

    Thanks Matt

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    Usually they are loose in middle. Pull the Y out and I would mike the OD or the screw. It maybe really buggered up in the middle and it is bragging in the middle. Here is a good show on taking them apart:
    YouTube around the 17 minute shows taking the Y axis out.
    The also sell new parts. H&W Machinery
    YouTube

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    Hi Richard,
    So I actually have it completely apart and can't turn the nut by hand in the middle. The outside of the nut has definitely seen better days. The feed nut assembly casting cracked so the previous owner just tightened the screw more as you can see on the brass. I plan on replacing the feed nut as it seems i have no choice with that damage. I have operated a bridgeport in college but never taken one apart until now. So, you would like me to mic the OD of the lead screw? or the actual thickness of the thread in several places? img_5315.jpgimg_5316.jpg

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    Mic thread OD. Check for a bend in the middle of that lead screw. I have seen similar damage to that casting from having a forklift run into the table ,bending the adjusting screw and breaking out that area of that casting.

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    Quote Originally Posted by mvernon View Post
    Hi Richard,
    So I actually have it completely apart and can't turn the nut by hand in the middle. The outside of the nut has definitely seen better days. The feed nut assembly casting cracked so the previous owner just tightened the screw more as you can see on the brass. I plan on replacing the feed nut as it seems i have no choice with that damage. I have operated a bridgeport in college but never taken one apart until now. So, you would like me to mic the OD of the lead screw? or the actual thickness of the thread in several places? img_5315.jpgimg_5316.jpg
    That bottom photo looks like that's a home made nut plus it's burnished and they may have squashed the nut. Bottom line is order a new bracket, new adjustment screws, new screw and nut assemblies. Be sure to clean, repair or replace the lube systems too

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    Yes. Its time for a new Y axis screw. You can see that one of the threads has a really weird wear. It's almost tapered.
    img_5321.jpg

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    If it's only one single thread is there any chance you can repair it with a tapered file (carefully of course)? A single damaged thread being repaired shouldn't effect accuracy too much, if at all, since the nut will span several threads around.

    Just a thought,
    Ted


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