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  • #16
    Originally posted by Stepside View Post
    ... There two parts bolted together but aligned with a pair if spring pins/roll pins. ...
    I don't quite get the picture: it sounds like the parts have flat surfaces bolted together, but then the pins wouldn't hold them together & the parts could be pried apart.

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    • #17
      From your description it's not clear if there is some length sticking out, but if so, drop a snug fitting dowel pin into the spring pin, then you can clamp onto it with pliers or vise grips without too much distortion. Lack it out with a prybar or old screwdriver.

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      • #18
        The pins are flush to the surface and it is not a through hole. It was late in a long day when I reached this point in the task. This morning I will go out and see if I missed something.

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        • #19
          I've had good luck on several occasions when I've had to remove flush fitting roll pins from a blind hole by welding a little knob onto the end of the roll pin. I use an .023 wire on a wire fed gun and try to direct the wire to make contact with the inside of the roll pin a bit down the inside of the pin in order to get some decent penetration and solid contact. Keep building the knob up in multiple passes until you have enough material to get a good purchase on it with a pair of side cutters, then lever it out using the side cutters.

          Those pins are hard to drill out so I've found this has worked the best for me.
          Home, down in the valley behind the Red Angus
          Bad Decisions Make Good Stories​

          Location: British Columbia

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          • #20
            I was assuming, as I think most of us were, that you had already managed to carefully pry the two pieces apart. And as such you had part of the pins sticking out one or other of the two pieces. If that isn't the case then I don't see why you can't remove the fasteners and then carefully pry the pieces apart from both sides so they stay fairly parallel the whole way so that half the pins are exposed. From there grab the ends with one of the ideas above and pull them out. I'm rather liking the end nippers and vise grips with slide hammer welded on.

            At that point I'd probably replace the spring pins with solid pins and slightly open up the holes on one of the parts so the pins stick solid in one of the pieces and slip fit the other so you or the next owner don't run into the same issue.
            Chilliwack BC, Canada

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            • #21
              Originally posted by Mcgyver View Post

              the pins are usually smallish and the problem with any sort of manipulation of the centre is 1) it makes it tighter in the bore and 2) if it breaks you are really pooched. Do what I said, bits of paper towel in grease and press it into hole, hammer with punch. do it 500 times if needed.... It takes some time but is a bit fool proof. The grease will keep squirting out, seemingly ineffective, but its depositing the fiber that eventually clogs the greases escape route. I've used it to pop a unshielded press fit bearing out of a blind hole for example, something close impossible most any other way.
              I don't see this working well with a 1/8 inch diameter roll pin. That would take a mighty small but rigid punch. I just checked a 1/8 roll pin and found that when compressed the center hole was only .079 inch diameter. I realized that I could sacrifice a small numbered drill bit to punch duty.

              Dan
              At the end of the project, there is a profound difference between spare parts and left over parts.

              Location: SF East Bay.

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              • #22
                If the parts are already apart, I would be tempted to use a side cutters/diagonal cutters to grab the pins and lever them out. That kind of sucks having a roll pin in a blind hole.

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                • #23
                  That's what I said.



                  Originally posted by Bob Engelhardt View Post

                  I don't quite get the picture: it sounds like the parts have flat surfaces bolted together, but then the pins wouldn't hold them together & the parts could be pried apart.
                  Paul A.
                  SE Texas

                  And if you look REAL close at an analog signal,
                  You will find that it has discrete steps.

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                  • #24
                    IF I have read correctly, the roll pins are broken off flush with the surfaces of Both mating parts. That is, the pins sheared during disassembly.

                    That's a tough situation at that small size.

                    As roll pins are made from spring temper material, and they are split to boot, drilling them will be a nightmare of broken bits. How many times can you say "SNAP".

                    I might consider using a nail shank at full pin diameter to act as a friction drill while turned with a fast drill motor,

                    With just the right combination of rpms and pressure, the stuck pins just might "soften" or even weld/ jamb on the nail to be pulled out. at minimum, the heat will change the spring temper. At worst, the pin will spin and wallow out the hole Then drill the parts for the next larger pin.

                    A small flame tourch might do as much regarding temper and softening. I would NOT try to drill into a roll pin with a small twist drill! NO WAY!!

                    In general, and if the pin does protrude from it's surface, always shove a supporting piece of wire or a drill bit into the roll pin before grabbing the pin with a end or side cutting pliers to pull it. another useful thing is to give the small pin a very light tap IN to break it;s grip on the bore.

                    Bottom line for me, Don't make things worse, and heat is my friend. ;-) Good luck!

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                    • #25
                      The pins were flush with the top of the assembly. I re-read the the service manual. It discussed removing the rear of the assembly. So if you are working at the back of the machine,is the is the back of the assembly facing you or is it the side away from you? Anyway I tried to drive the pins deeper with a punch and when they bottomed out the parts started to move away. Then with careful use of pry bars it came apart. New belts are installed and it is ready to go back on the machine. I will put instructions in the service manual for the next owner.

                      Thanks for all the different ideas and techniques.

                      Pete

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                      • #26
                        It's done now, but one suggestion I had would be to insert a slightly loose fitting pin (music wire perhaps) and hit it with some current from a welder. You might be able to get enough of a spot weld in there for a grip- then clamp a vice grip on the wire and leverage against that to pull it out.
                        I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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