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Thread: Noisy Bridgeport Head

  1. #1
    Join Date
    Aug 2009
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    2,494

    Default Noisy Bridgeport Head

    Several years ago I bought a real nice Bridgeport mill. It had the step pulley head. Shortly after that I found another that had a variable drive head, which I wanted. So I bought that mill also but it was whipped. I pulled the head and completly went through it. I replaced all the bearings in the head and the motor as well. The bushings on the two sheaves were tight. I put that head on my mill. Lately it's become very noisy. Aside from the slight rattle where you engage and disengage the spindle which I know what that is. That castelated coupler, It's very loud at low speeds. If I disengage the spindle it's still noisy. As I speed it up it starts to quite down. As I dial it down it starts to get noisy just about at the lowest it will go. It sounds mostly like belt noise with a pulsating rythem to it. I have removed the belt and the motor is dead quite. Any suggestions. Sometime this winter I will tear it down again and hopefully know what to look for.

    JL........................
    Last edited by JoeLee; 09-15-2009 at 10:47 PM.

  2. #2
    Join Date
    Jan 2007
    Posts
    112

    Default

    in order of likelyhood... theres a plastic bushing in moving sheave on the motor it gets baggy rebush that, the belt is cracked or smoked , the front moving pulley sheave, the variable speed thrust ball bearing might be shot

  3. #3
    Join Date
    Jun 2004
    Location
    Austin,TX
    Posts
    934

    Default

    I worked on one a couple of years ago that had a lot of wear in the coupler and it made a fair amount of racket. The way to test it is to run the mill up to high speed and then push on the back gear lever to see if the sound dramatically changes. H&W has the parts ( http://www.machinerypartsdepot.com/s...57/page/547181 ), they are a little pricey but they will get it fixed.

  4. #4
    Join Date
    Aug 2009
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    2,494

    Default

    The coupler is worn a bit as I mentioned in my post. If I push the back gear lever up it quiets it down a little but they are worn past the point adjustment. The bushing on the pulleys are tight, also mentioned that.
    I replaced the belt with a new Gates belt, I thought that might be the problem since it was a little stiffer than the original, it made no difference so I put the original back in, it was much more flexable and in good shape.

    JL................

  5. #5
    Join Date
    Jun 2005
    Location
    Mapleton, IL
    Posts
    2,283

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    You mentioned replacing all the bearings in the head....does that include spindle bearings and the back gear idler support bearings etc. ? How about the upper spindle support bearing at the top of the belt housing? The darned things have bearings all over the place and all it would take is one bad one to make that sort of noise. Now that I think of it you mentioned that if you disengage the spindle (move the back gear lever half way?) it's still noisy.

    I would look for looseness of the pulleys on either end. Pulleys vibrating against either a drive or driven shaft are always a potential source of noise.

    Edit-- you did mention a "slight rattle" due to the castellated interface, with regard to engaging and disengaging back gear, but it's important to keep in mind that as a source of noise at all times....not just when monkeying with the engagement/disengagement....at least it is on my VS head. A tiny bit of load (hand rubbing on spindle) will usually squelch it though. I noticed on disassembly that there is that sort of iron-oxide staine appearance to much of the castellated interface surface....the color that comes from constant rubbing of two ferrous pieces. I believe that there is some chatter in there at all times because even with new parts, it's not an extremely tight fit. It can't be or it would be cantankerous trying to get things to mesh.

    Paul
    Last edited by pcarpenter; 09-16-2009 at 10:24 AM.
    Paul Carpenter
    Mapleton, IL

  6. #6
    Join Date
    Nov 2007
    Location
    Woodinville, WA
    Posts
    5,056

    Default

    ...and another source -worn splines on the spindle shaft, and/or wear in the matching internal spines of the dog clutch parts.

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