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  • Bridgeport fine feed issues and questions

    I've never owned nor operated a Bridgeport before so I don't know quite what to expect as I get my new-to-me Bridgeport "tuned up" and working.

    So far only the main quill feed handle is operational. I don't neccessarily need power feed (I understand it is rather "wimpy") but I do want the fine feed handwheel to work.

    I'm replacing missing parts as I find them. So far, I found that the "outboard side" of the overload clutch assembly, and detent ball & spring for the Reverse Knob were missing.

    I knew some of these parts were missing when I purchased the mill, so this comes as no surprise. Don't know if these parts were pilfered to put on other machines at some point, or were removed because the head is otherwise in some state of disrepair.

    I found the clutch parts on Ebay, and will buy the detent ball and spring this week.

    In order for the fine feed handwheel to work, the Bridgeport manual states that the Power Feed Transmission Crank must be disengaged and the handwheel reverse knob must be in the nuetral position.

    Questions:

    1. I'm unable to get the Power Feed Transmission Crank to fully disengage. The knob just won't "get there" (see pic below). I've tried every permutation of simultaneously wiggling and manually turning all the other controls and the spindle and pulleys (short of turning the motor on) while attempting to get it to turn counter-clokwise to the "OUT" detent but no joy. Is there some "unpublished" sequence to it? It will turn clockwise to the "IN" detent just fine.

    2. Regarding the "Power Feed Transmission Crank", the placard on the mill uses "IN and OUT", the Bridgeport manual uses "Engage and Disengage" vernacular. I'm assuming "IN" means "Engage". Correct?

    3. The clutch seems to be operational now that all the parts are in place, but the trip handle doesn't seem to want to stay in either the engaged or disengaged position. Is there some detent mechanism somewhere, similar to the reverse knob ball and spring detent? The exploded views I'm finding on the web are pretty poor quality and small.

    4. If I manually hold the trip handle in the engaged position, the hand wheel will extend and retract the quill. Is this correct?


    Last edited by jmarkwolf; 03-16-2013, 08:43 PM.

  • #2
    Hard to tell the exact problem from your explanation. Since it could be a number of things internally, if it were me I would start taking things apart. You should be able to find several exploded views of the internal working of the head. I have never had a problem takking mine out of gear but sometimes have a bit of trouble putting it into gear as I have to nudge the spindle or bump the motor to get the gears to mesh and then it'll fall right in.

    JL.................
    Last edited by JoeLee; 03-16-2013, 10:44 PM.

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    • #3
      Here is a diagram............ I would suspect #17 through #23 to be the problem area. It's been a while since I had mine apart.
      http://www.practicalmachinist.com/vb...uilder-150143/

      JL........................
      Last edited by JoeLee; 03-16-2013, 10:51 PM.

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      • #4
        If your feed handle won't stay out, there is something to check to the left of the 1/2-20 screw is a rod of about 1/2" while holding the feed lever out try turning the rod and pulling it down, that is the release of the feed rod when the quill is fed down to the adjustable stop nut.

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        • #5
          Jmarkwolf put your location in, there could be some one near you that could help. No location no help, unless your in the witness protection program.

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          • #6
            Go onto E-Bay and buy SWells book on rebuilding the Bridgeport, if it is as good as the Lathe book it will be money well spent.
            Jon

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            • #7
              Looking at your picture it looks like you've gone past disengage (out) if your swinging the arm under it's piviot point which is the way mine works. I can go past disengage and end up about where you are in your picture and it stops. I've never tried rotating the lever all the way around.
              Anybody???????????

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              • #8
                Yes to the trip handle question. If the lever doesn't stay out by it's self it may just need a good cleaning, that whole set up is touchey.

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

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                • #9
                  Originally posted by JoeLee View Post
                  Looking at your picture it looks like you've gone past disengage (out) if your swinging the arm under it's piviot point which is the way mine works. I can go past disengage and end up about where you are in your picture and it stops. I've never tried rotating the lever all the way around.
                  Anybody???????????
                  Hi JoeLee

                  My arm doesn't swing "under it's pivot point", only over. And it just won't get to both detents.

                  Although, now that I look closer at the photograph, the witness marks look like it used to swing under the pivot point.

                  I've been trying to get a sense of how the Bridgeport head is supposed to work before I dismantle anything, but I may not get that luxury.
                  Last edited by jmarkwolf; 03-17-2013, 07:53 AM.

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                  • #10
                    Originally posted by duckman View Post
                    Jmarkwolf put your location in, there could be some one near you that could help. No location no help, unless your in the witness protection program.
                    Good idea duckman

                    I'm in southeast Michigan, near Ann Arbor. I edited my profile to include this.

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                    • #11
                      I just found a Tubalcain video on You Tube that describes the action of the various J-head controls (http://www.youtube.com/watch?v=7oB7B_eJi6A).

                      Very informative! I'd never seen this before! I've been using a mill/drill for nearly 15 years.

                      I learned, from watching the video, that my Power Feed Transmission Crank does indeed swing the wrong way as pointed out by JoeLee. Don't know why this would be the case. I removed the assembly and couldn't see anything outwardly amiss in there, the parts all seem to be free to move. I experimented while re-installing the assembly but it only want's to go on in one orientation. Still a mystery at this point.

                      I also learned that my hand-wheel clutch is supposed to spin when the motor is running. Mine does not. Pushing and pulling the reverse knob has no effect. So it appears more parts have either been pilfered from my machine, or are broken.

                      This isn't a job, it's adventure!

                      Will advise here as I find the solutions.

                      Comment


                      • #12
                        I think the problem might be the position of PN#18 in the diagram. It sounds like something is 180 deg. out. The arm should swing under, I've never seen one that worked the opposite. Someone may have had it apart at one time and messed up.

                        JL......................
                        Originally posted by jmarkwolf View Post
                        Hi JoeLee

                        My arm doesn't swing "under it's pivot point", only over. And it just won't get to both detents.

                        Although, now that I look closer at the photograph, the witness marks look like it used to swing under the pivot point.

                        I've been trying to get a sense of how the Bridgeport head is supposed to work before I dismantle anything, but I may not get that luxury.

                        Comment


                        • #13
                          Update:

                          I tried "phasing" the "crank" arm (23) relative to the shift sleeve (19), and playing with the way the pin on the end of "throw-out arm" (18) engages the "feed engage pin" (16).

                          The only orientation that allows anywhere near 180 degree of motion on the "shift crank" (23) is the original orientation described previously above. All other possible orientations seize the crank when I spin the cap screws (25) down.

                          The bottom line is: the only way the crank will turn at all, is above the pivot point as described previously, and will not "reach" both detents.

                          This leads me to suspect:

                          1. The "crank" (23) and the worm gear cradle "throw-out shaft" (18) have somehow gotten out of proper "phase" to each other to control the worm gear cradle properly, although the roll pins are still in place in both,

                          and/or

                          2. The worm gear cradle is broken somehow and is not moving properly.

                          Everything seems to be fairly wet with oil.

                          From what I can see by looking into the opening and poking around with a screwdriver, the feed engage pin (19) is free to move vertically. The worm gear cradle appears to move vertically perhaps 0.100", and laterally approx. 0.250". I have no idea if this proper.

                          I expect the work gear cradle has to have some freedom of movement "slop" due to the rotary nature of the pin on the end of "throw-out shaft" (18), correct?
                          Last edited by jmarkwolf; 03-17-2013, 09:38 PM.

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                          • #14
                            I don't remember the exact details but it is indeed possible to have the feed engage lever 180 degrees out of correct positioning and this will result in your symptoms.
                            Don Young

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                            • #15
                              I found the problem.

                              I dismantled the top end of the head (easier than I had feared), and immediately found that the small Feed Bevel Pinion Gear at the end of the worm gear cradle, had broken off and jammed the cradle.

                              I had started the related thread below last weekend when I came to believe the source of the issue was going to be the cradle. Posted the pics there.

                              "Trying to understand the Worm Gear Cradle on a series1 step head"

                              Thanks for all the ideas everybody!

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