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  • Found more detail on my Bridgeport head noise

    I pulled things back apart today to see if I could find anything out of place. The clutch dogs look okay to me, but there are others here who know better and might tell me different:

    [IMG][/IMG]

    [IMG][/IMG]

    The one thing I did find, mostly just because it cut my finger, is that the ring around the bottom of the timing belt splines (timing pulley clutch sleeve, I think) has been mushroomed out to a very sharp edge- it may be difficult to see in the picture. Have I been bottoming the sleeve out against the bull gear? If that surface has been riding against the bull gear, could that cause the clutch dogs to knock against each other? I am only hearing the noise in high gear, which is the only time the clutch dogs are engaged. I am wondering if I have had them seated too far together.

  • #2
    These works best when togther! Yes, it is a typical source of BP noise.

    Strangely your dogs don't look very worn at all, but it doens't take much. Note that they are slightly tapered. If they wear, the tapers no longer lock. Some aftermarket parts aren't the best.

    This is one area where the "floating in" (aligning the upper to lower head spline portion) works well.

    Comment


    • #3
      Originally posted by lakeside53 View Post
      These works best when togther! Yes, it is a typical source of BP noise.

      Strangely your dogs don't look very worn at all, but it doens't take much. Note that they are slightly tapered. If they wear, the tapers no longer lock. Some aftermarket parts aren't the best.

      This is one area where the "floating in" (aligning the upper to lower head spline portion) works well.
      Am I doing anything wrong to have that sleeve getting mushroomed out like that? It sounds like the "floating in" step allows these dogs to fully seat together.

      Also, do you think I have aftermarket parts on my mill? I only know about the parts I have replaced- not the parts that may have been replaced before I bought it.

      Comment


      • #4
        I haven't seen one mushroomed, and I've seen inside of many that were badly worn. Hard to say if you have aftermarket or not; they look the same and in most cases work, but I had a couple of dog pairs what wouldn't seat properly until I filed the male portion slightly to ease. Your problem appear different. Clean up that skirt on a lathe and see if you can feel what's happening.

        I don't see much evidence of galling on the mating portion. IRRC the skirt is heated then shrunk onto the main body. Any chance it came loose or moved?

        I have a brand new 2J drive dog I can take a picture, or or measure the skirt if you need.

        Comment


        • #5
          There's all kinds of reasons they can make noise esp. in high gear,

          one of the most common problems is a dry spline drive coupled with even minor belt deviation - it's an annoying "rattling" sound that goes away as soon as you load the spindle some - even with your hand.

          Belt deviation can also effect your drive dogs if dry and your gears if they have excessive backlash.

          At higher RPM's the spindle stores momentum and wants to remain at a stable 360 degree revolution - so does the electric motor that's driving it from the other end - the "argument" between the two is usually created by a variable deviation of some sort that is actually trying to speed the spindle up and slow it down all within milliseconds - actually just about all belts have some deviation, if it's minor just the pre-load of the spindle bearing and grease drag and so forth will keep all components loaded to the drive side and there will be no issues with either wear or noise,

          if it exceeds the drag rate at a speed greater than what the motor and gearing is allowing (due to deviation) then it will inevitably have to also fall off the mark, this will then allow the spindle to over accelerate the rest of the components of the drivetrain - any and all drivetrain "lash" or "slack" will be taken up if the deviation is great enough - it's even common in situations like this to see wear patterns on the non-drive side of components with certain other types of machinery that does not have any kind of reversing mechanisms,,,

          Now you not only have a noise - you have a fretting action that will increase wear,,,

          Now enter dry components and both your noise and your wear get amplified and accelerated....

          Sometimes when a belt is acting up you can flip it over and it will make the situation go away, but other times it will make it worse,
          this is due to the positive and negative pulses that the belt is creating - deviated belts are like variable drivetrain rubber bands with weak spots and strong spots - some ramp up slowly with the positive and then drop off quick with the negative, when you flip them this can be reversed...
          whether or not one way will help more than the other depends greatly on drivetrain geometry and gearing and mass and speed of components... needless to say - it gets involved - but with some machines a simple flip of the belt to find out does not... can be a great simple diagnostic tool...
          Last edited by A.K. Boomer; 11-10-2012, 05:38 AM.

          Comment


          • #6
            Take a look at the picture in post #29. Did you find anything like that part in your head? I found this piece laying in the housing under the motor sheave and couldn't figure out where it went. I put it back together without the part and it runs fine.
            http://bbs.homeshopmachinist.net/thr...variable+speed

            Brian
            OPEN EYES, OPEN EARS, OPEN MIND

            THINK HARDER

            BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

            MY NAME IS BRIAN AND I AM A TOOLOHOLIC

            Comment


            • #7
              Originally posted by A.K. Boomer View Post
              There's all kinds of reasons they can make noise esp. in high gear,

              one of the most common problems is a dry spline drive coupled with even minor belt deviation - it's an annoying "rattling" sound that goes away as soon as you load the spindle some - even with your hand.

              Belt deviation can also effect your drive dogs if dry and your gears if they have excessive backlash.

              At higher RPM's the spindle stores momentum and wants to remain at a stable 360 degree revolution - so does the electric motor that's driving it from the other end - the "argument" between the two is usually created by a variable deviation of some sort that is actually trying to speed the spindle up and slow it down all within milliseconds - actually just about all belts have some deviation, if it's minor just the pre-load of the spindle bearing and grease drag and so forth will keep all components loaded to the drive side and there will be no issues with either wear or noise,

              if it exceeds the drag rate at a speed greater than what the motor and gearing is allowing (due to deviation) then it will inevitably have to also fall off the mark, this will then allow the spindle to over accelerate the rest of the components of the drivetrain - any and all drivetrain "lash" or "slack" will be taken up if the deviation is great enough - it's even common in situations like this to see wear patterns on the non-drive side of components with certain other types of machinery that does not have any kind of reversing mechanisms,,,

              Now you not only have a noise - you have a fretting action that will increase wear,,,

              Now enter dry components and both your noise and your wear get amplified and accelerated....

              Sometimes when a belt is acting up you can flip it over and it will make the situation go away, but other times it will make it worse,
              this is due to the positive and negative pulses that the belt is creating - deviated belts are like variable drivetrain rubber bands with weak spots and strong spots - some ramp up slowly with the positive and then drop off quick with the negative, when you flip them this can be reversed...
              whether or not one way will help more than the other depends greatly on drivetrain geometry and gearing and mass and speed of components... needless to say - it gets involved - but with some machines a simple flip of the belt to find out does not... can be a great simple diagnostic tool...
              Thanks for all of the information. You mention having a dry spline drive with belt deviation and also how dry components accelerate wear and amplify noise. I am not sure if you are suggesting that the clutch dogs need to be lubricated or if you are just talking about the inherent short comings of the Bridgeport dry-spline, belt-driven design. Is there something I should be lubricating that I am not?

              Comment


              • #8
                Originally posted by lakeside53 View Post
                I haven't seen one mushroomed, and I've seen inside of many that were badly worn. Hard to say if you have aftermarket or not; they look the same and in most cases work, but I had a couple of dog pairs what wouldn't seat properly until I filed the male portion slightly to ease. Your problem appear different. Clean up that skirt on a lathe and see if you can feel what's happening.

                I don't see much evidence of galling on the mating portion. IRRC the skirt is heated then shrunk onto the main body. Any chance it came loose or moved?

                I have a brand new 2J drive dog I can take a picture, or or measure the skirt if you need.
                I think a picture of a new set of drive dogs and maybe a measurement of the skirt would be helpful. I don't have access to a lathe, but I will see what I can do about cleaning things up before I put it back together.

                Comment


                • #9
                  Originally posted by jh628 View Post
                  Thanks for all of the information. You mention having a dry spline drive with belt deviation and also how dry components accelerate wear and amplify noise. I am not sure if you are suggesting that the clutch dogs need to be lubricated or if you are just talking about the inherent short comings of the Bridgeport dry-spline, belt-driven design. Is there something I should be lubricating that I am not?

                  Im no BP expert here - just a mechanic that's worked on a few, so maybe someone will chime in with something you can use, I sure would not run the either the dogs dry or the splines - for the dogs in the pick I would look for a thicker waxy type grease - for the splines I would use some Exeddy automotive clutch spline grease - it won't sling off, is resistant to drying out and has all kinds of good quality lubricating ingredients - come to think of it It might work good on the dogs also...

                  Comment


                  • #10
                    Originally posted by A.K. Boomer View Post
                    Im no BP expert here - just a mechanic that's worked on a few, so maybe someone will chime in with something you can use, I sure would not run the either the dogs dry or the splines - for the dogs in the pick I would look for a thicker waxy type grease - for the splines I would use some Exeddy automotive clutch spline grease - it won't sling off, is resistant to drying out and has all kinds of good quality lubricating ingredients - come to think of it It might work good on the dogs also...
                    Amsoil makes a spray that they call a "heavy duty metal protector" that is excellent for such places. It sprays on thin, but sets up to a waxy substance that stays in place and won't sling off. Also excellent on change gears on the lathe.

                    Comment


                    • #11
                      Sounds like good stuff - am familiar with their oil and like it allot,

                      Now it's got me wondering if BG has anything like that? Yet another company iv come to trust their products over the years.

                      The Ams sounds like the ticket for the dogs for sure - and maybe the splines but I think you have to be careful with waxy on them - could make for a really slow quill return esp. if one keeps their shop somewhat cool.

                      Comment


                      • #12
                        This is interesting....... my BP has made the same kind of noise even after I replaced all the bearings and sheave bushings. After that I always thought it was the play in the clutch dogs but it isn't as they can be adjusted to engage tightly which they are. It's dead quiet in neutral through out the speed range, just knocks and rattles in high range and at the lower end of the range it gets worse. I did replace the belt, not with an original BP but a Gates look alike. I might try some of that metal protector stuff mentioned in the previous post.

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

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