Announcement

Collapse
No announcement yet.

moving deck cam follower shaft broken bolts

Collapse

Adsense Classic 1

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • moving deck cam follower shaft broken bolts

    We all know this tune.

    For a while I was replacing these with the Quality studs but I just about every one I put in has broken. They always break off flush with the end of the shaft. Pondering this I came up with the theory that, since the Quality part has an enlarged, unthreaded portion right in the middle and, since this oversized area comes to bear on the shaft when the stud is tightened into place, the stud is breaking because of stress caused by the above.

    Lately I've been making my own studs out of grade 8 bolts. Since there is no unthreaded area I am able to bottom out the stud in the bore of the shaft. Seems to be working out well.
    If you think my girlfriend can fight, you should see her box!

  • #2
    I have so far had good luck with the shaft kits with stud and lock collar from AMF I purchased years ago. Make sure to check the mounting plate for any loose bolts. On the machines that don't have the kit installed I replace the factory bolt every two years with a good North American made one. I don't give it a chance to fatigue and fail.

    Comment


    • #3
      If these are converts then earlier hard shifting MD/S cams could play a role.

      I have old and new MD/S cams and can't say I have an issue with the studs; heck I still have many grade 2 bolts in play. You might have a bad batch of studs. JMO
      Factory & Converted A-2 (US, Ger, Jap)
      Comscore ECT, Matrix & DuoHD
      Walker B, Sanction Standard, Original K, Flex Walker & Ikon
      Kegel C.A.T.S

      Comment


      • #4
        After 30 plus years permanent and casual can only remember perhaps 3 broken bolts in this shaft.
        If you're experiencing numerous broken bolts I suspect other factors are at play. James has offered a couple of credible suggestions.
        The moving deck cam follower is lubed and free of any bind on the stud/shaft?

        Comment


        • #5
          Spoke with a number of mechanics who say they break any grade of this bolt, whether it is a 2, 5, or 8. Some of us have the theory that the "Hard" Moving Deck / Scissor Cam is part of the problem, as James stated. The faster Jet Back and A2 speeds further exacerbate, (ooo big word), the problem. Loose bolts on the mount plate don't help either. Over time, the shaft and/or mount plate wear. This slop also puts stress on that bolt. I would have my pinchasers lower the deck to 270, remove the cable, and check the bolt for tightness. That way when it broke, it would be an easy fix. Then I made a major change. I took the shafts to a machine shop. Had them machine a flat spot on the shaft so I could put a wrench on it, rather than marring it up with pliers or a vice grip. They bored out the shaft to accept a 7/16" bolt.

          I removed the rear bolt on the shotgun from the Rake Cam Follower so I can move it forward, then used a long drill bit with a right angle drill, and bored out the gearbox. I then installed a Grade 2 - 7/16" bolt. I checked with Brunswick engineering before doing this. They said it was OK to do this. Have never broke one in over 35 years.

          I know many folks use the "collar" which is a fair band aid but the bolts still break. Griz's idea of replacing the bolts with good American products is also a good idea.

          See the pics of the shaft. It is very dark as I store them in plastic bags after coating them with 90/140 gear oil so they don't rust.

          ALL Files Scanned with MALWAREBYTES PREMIUM Version 3.7.1.2839 and AVAST INTERNET SECURITY Version 18.6.2349

          Deck Cam Follower Shaft 2C.jpgDeck Cam Follower Shaft 1C.jpgRake Cam Follower C A.jpg
          Everything has to be Somewhere !!

          Comment


          • #6
            Nice mods you have there Mickey!

            Originally posted by mickeygm View Post
            I know many folks use the "collar" which is a fair band aid but the bolts still break.
            I wouldn't call it a band aid, it was conceived as a cheap backup for when/if the bolt breaks. I consider it a required part to have on all machines.
            Factory & Converted A-2 (US, Ger, Jap)
            Comscore ECT, Matrix & DuoHD
            Walker B, Sanction Standard, Original K, Flex Walker & Ikon
            Kegel C.A.T.S

            Comment


            • #7
              I guess we are going to have to agree to disagree on this one. When Brunswick, PPP, or any of the other after market vendors, redesigns a part that NO Longer fails, it is a permanent Fix. Example - the Rake can follower on the original machines was Under designed, It would bend and twist, usually because of the rake getting hit. So they came out with the current follower, (in my third pic), big thick steel, that no longer fails. A permanent fix. The collar simply keeps the shaft from moving out after the bolt breaks, which then eventually hits the Moving Deck / Scissor cam, which in turn bends the heck out of the mount plate or breaks the cover. Now you get to do a 1:1. It is a "Band Aid" because it does Not Fix the problem. The 5/16" bolt is under designed. The hard cam, faster machine speeds, wear of the shaft and mounting plate and who knows what else all contribute to it's failure. The 7/16" bolt is a permanent fix.
              Everything has to be Somewhere !!

              Comment


              • #8
                After years of working on these machines and lots of observation I came to the conclusion that the main thing which causes the moving deck cam follower shaft bolt to break regularly is when the 3 large countersunk bolts for the 1:1 plate come loose - especially the lower one near the moving deck/scissor flag.

                If you see the detector "bounce" just after 180 degrees it is usually due to one or more of the countersunk 1:1 plate bolts starting to come loose (as I said, the main offender is the lower one near the scissor/moving deck flag).

                In this scenario the 1:1 plate is actually moving up and down (with the detector attached to it, of course). Because the moving deck cam follower shaft goes through the hole in the 1:1 plate and the other end of the shaft is bolted to the gearbox the plate end of the shaft moves up and down with the "bouncing" of the plate while the gearbox end (with the bolt) doesn't move. This puts excessive stress on the bolt which will eventually break it - the more "bounce" in the 1:1 plate/detector the sooner the bolt will break.

                Comment


                • #9
                  I remember when the collar first came out. In the late 70's or maybe 80's, Brunswick would put out a newsletter. They would give some sort of award to mechanics for their ideas. Some mechanic received an award for the collar. Why Brunswick did not redesign this part is beyond me, ( oh wait, selling covers and mounting plates is good business ). They have beefed up and redesigned so many of the original parts, but they never fixed this one. Good point on the loose bolts. I used a little lock tight to keep them tight.

                  Don't know if anyone noticed the hole in the Rake Follower just below and to the right of the yellow arrow. That's where part of the old cable triggering was attached.
                  Everything has to be Somewhere !!

                  Comment


                  • #10
                    Good points Mickey, I now understand your reasoning for calling it a band aid.

                    I tend to agree with Carl with the reason a larger bolt/stud would be required. From a field mechanics POV a larger bolt/stud and/or securing the cover and plate is a good solution. An engineer would assume with all hardware correctly installed a 1/2" bolt would be all that's needed to retain the shaft and anchor it under expected circumstance. No consideration would be given for loose hardware or poor maintenance since the machine would become so over engineered they'd be priced out of production.

                    There are many areas of these machines we could all agree need some design/build improvements me thinks.
                    Factory & Converted A-2 (US, Ger, Jap)
                    Comscore ECT, Matrix & DuoHD
                    Walker B, Sanction Standard, Original K, Flex Walker & Ikon
                    Kegel C.A.T.S

                    Comment


                    • #11
                      Just to add a little more to my previous post (for Australian built machines) - the "bounce" of the 1:1 plate and detector caused by the loose plate bolts was also exaggerated by the original adjustments in the manual for the Australian built Brunswick Model A's (made in Lane Cove, New South Wales).

                      These are the only original Model A's I have worked on. We were informed sometime back in the 90's that there was a manufacturing fault with the "rabbit ears" on the ends of the rake lift shafts when these machines were built. The 'rabbit ears" were apparently welded onto the shaft slightly out of position from where they were supposed to be which caused the rabbit ears to hit the cross brace underneath it at 180 degrees (if the adjustments were done by the book) - sometimes quite severely judging by some of the huge gouges in the cross braces and rabbit ears that I saw at the old Fairlanes City Bowl where I worked until it closed at the end of 2006.

                      This contact between the rabbit ears and cross brace would make the 1:1 plate/detector bounce more noticible at just past 180 degrees which also accelerated the loosening of the countersunk plate bolts and the eventual breaking of the MD cam follower shaft bolt.

                      After doing the revised adjustments (which mainly involved lengthening the link between the top of the rake cam follower and the rake lift shaft from memory) the rabbit ears no longer hit the cross brace underneath which reduced the "bouncing" of the detector and plate but didn't eliminate it entirely on some machines (I'm guessing in these cases the holes in the plate for the 3 countersunk bolts may have enlarged a bit through wear). After replacing the 1:1's on some of these machines we had no more issues with MD cam follower shaft bolts breaking - at least up until the closure of the bowl.

                      Comment


                      • #12
                        Good point on the cover. I don't remember them coming loose on my old machines or even the 90000 Japanese ones but I can easily see this happening. I do remember putting a little lock tite on these when I would do a 1:1. I will pass this on to the other mechanics in the area. I think if they had put a 1/2" bolt in there,there would not have been a problem but I think that may have been too big for the shaft. The 5/16" bolt is just too small. I bypassed the 3/8" choice and went up to a 7/16".

                        I was just sour grapes when Brunswick made such a big deal about the collar when I had asked them about going to the 7/16" bolt, (and they knew it).
                        Everything has to be Somewhere !!

                        Comment


                        • #13
                          Originally posted by Kanga (James) View Post
                          An engineer would assume with all hardware correctly installed a 1/2" bolt would be all that's needed to retain the shaft and anchor it under expected circumstance.
                          Correction: That was meant to be 5/16" (OEM size).
                          Factory & Converted A-2 (US, Ger, Jap)
                          Comscore ECT, Matrix & DuoHD
                          Walker B, Sanction Standard, Original K, Flex Walker & Ikon
                          Kegel C.A.T.S

                          Comment


                          • #14
                            The machine are converted A's and they do appear to shift pretty hard.

                            My previous center had full blast Jap A2s and I never had a broken bolt that I can remember.
                            If you think my girlfriend can fight, you should see her box!

                            Comment


                            • #15
                              Interesting story Carl.
                              I've noticed the marks in the cross brace on my lane cove machines from 2 centres. Never realised it was just the jig at lane cove that caused the problem.

                              Here is a picture of the marks that Carl is talking about.
                              Attached Files

                              Comment

                              Topic Starter RibbonScript

                              Collapse

                              Adsense Classic 2

                              Collapse
                              widgetinstance 666 (Related Topics) skipped due to lack of content & hide_module_if_empty option.
                               

                              Oil in gutters

                              I have a Kustodian ion Lane machine. I have recently replaced the oil tip assembly and hose. Recently I have been noticing about every couple feet in the gutters I am getting...
                               

                              C1 Pinout drawing

                              Finished the C1 drawing.

                              The base for this came from a drawing made by Felix dated 2006.

                              Thanks Felix.




                              If you see any...
                               

                              CCD Processor Move by Masternut

                              These are pictures submitted by "MASTERNUT" of a project in his bowling center where he moved his CCD processor boards from the location on the capping to the curtain...
                              Working...
                              X