Bridgeport collet key thread 1/4-32???
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  1. #1
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    Default Bridgeport collet key thread 1/4-32???

    I recently had an issue with the collet key in the spindle on my Bridgeport. When I got the locking set screw out it crumbled into 4 pieces. If I measure the screw with the key on it I get 1/4-32...is this correct? Where the heck do I find a set screw that size?

    Will I be ok running without the locking screw? I don't want to remove the key, I know some do.

    Any input would be greatly appreciated!

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    There are many people that sell Bridgeport parts. Bridgeports number is 800-843-8801

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    If you're correct and the thread is indeed 1/4-32, you can buy extra-fine socket cap screws from McM and make your own:

    Black-Oxide Alloy Steel Socket Head Screw 1/4"-32 Thread Size, 3/4" Long

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    The screw isn't needed...never had a problem with collets slipping (good condition spindle taper and hardinge collets), or the ability to start tightening the collet without that pin. Plus, folks have said if a collet does slip, it can shear off that pin and score up the spindle.

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    I bought my new Rockwell mill with R8 spindle in 1974. It was designed and built without a collet key in the spindle. I have never had a need for a key and I have read comments from Bridgeport owners who have said their mills work fine without a key. The key would be needed if your drawbar or R8 collet/tooling has a bad thread so that the draw bar will not freely rotate in the tooling threads. In that case, the spindle key would act to keep the tooling from turning in the spindle while you rotate the draw bar in either direction. My drawbar and my tooling threads are still in perfect condition, so I do not need a key.

    A sheared or loose key needs to be completely removed in order to prevent damage to your collet/tooling shanks.

    Larry

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    Quote Originally Posted by rickseeman View Post
    There are many people that sell Bridgeport parts. Bridgeports number is 800-843-8801
    Unfortunately I just can't order from anywhere.

    Quote Originally Posted by Milland View Post
    If you're correct and the thread is indeed 1/4-32, you can buy extra-fine socket cap screws from McM and make your own:

    Black-Oxide Alloy Steel Socket Head Screw 1/4"-32 Thread Size, 3/4" Long
    Thats an idea, I looked for set screws but not at shcs.

    [QUOTE=car2;3829919]The screw isn't needed...never had a problem with collets slipping (good condition spindle taper and hardinge collets), or the ability to start tightening the collet without that pin. Plus, folks have said if a collet does slip, it can shear off that pin and score up the spindle.[/QUshe's.

    I know it's been done I'm just not a fan.

    Quote Originally Posted by L Vanice View Post
    I bought my new Rockwell mill with R8 spindle in 1974. It was designed and built without a collet key in the spindle. I have never had a need for a key and I have read comments from Bridgeport owners who have said their mills work fine without a key. The key would be needed if your drawbar or R8 collet/tooling has a bad thread so that the draw bar will not freely rotate in the tooling threads. In that case, the spindle key would act to keep the tooling from turning in the spindle while you rotate the draw bar in either direction. My drawbar and my tooling threads are still in perfect condition, so I do not need a key.

    A sheared or loose key needs to be completely removed in order to prevent damage to your collet/tooling shanks.

    Larry
    My key is fine, for some reason it was backed out a bit.

    Really though why 1/4-32?!?!

    Thanks for the replies

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    Anyone else?

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    I don't know what the size is, but I haven't used that screw on a BP in 30 years.

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    I put it in with loctite

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