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  • #46
    The rollers you were looking at had a 1.5mm center diameter. Pretty small.

    Not sure how you're assembling this with a shaft.

    I'd use a bolt instead of a shaft. Place a nut on either end of the roller. Loose, and the roller rotates on the bolt. For a smoother rotation, add a roller bearing to the bolt. Words fail me here. These pictures fail me too!

    Click image for larger version

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    This is not the best, before I invest more time, what's with the shaft?

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    • #47
      Not sure how the images above work exactly. I plan to do a simple mount first to test if I can sync the film. Got another set of rollers from amazon:
      https://www.amazon.com/gp/product/B088BXFT44/
      These are 2.5mm inner diameter.
      Will drill one of the rollers for a press fit onto the stepper shaft. The other roller will be used with the 2.5mm shaft. The shaft is press fit into the roller. The other side of the shaft goes through a hole in a piece of plastic block with a stopper on each end. Then somehow arrange the plastic block close to the stepper to form a pinch assembly. Click image for larger version

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      • #48
        Hi David. I am still working on a simple pinch roller proto. Got a few parts today and will try to put something together. In the meantime the images that you posted are. or at least one of them is from the Kinograph project.
        https://forums.kinograph.cc/t/my-rpi...mms-design/639
        It is based on rpitelecine
        https://github.com/Alexamder/rpitelecine
        The github project contains all the necessary info to build the project including the mechanical.
        The pinch roller design looks pretty good but I do not have the 3D printer to experiment with it. Not sure what material is used. Should not be to rigid.
        https://github.com/Alexamder/rpitele...ler-detail.jpg
        The tension is controller by a rubber band in the bottom of the image.
        The idler arm could have some play because the idler roller fits into the stepper roller which eliminates the lateral play. In my case the rollers are not locked together and the lateral play must be minimized.



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        • #49
          Sorry about that last post, I should have deleted it! I was in a hurry and tried to find some pictures to explain my point.

          I thought you ordered different rollers with very small inner dia.

          I see how the shaft works now. I was suggesting a bolt that could be mounted to any bracket.

          And now I have that parts list, thankyou for that link!

          And here is a picture from that list showing a bearing. Not neccessary up front. Your plastic block should be ok.
          Click image for larger version

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          I'm sure (without looking) I can print from that parts list. I will take a look at it tomorrow.

          I once printed a set of film rewinds and used roller skate sized bearings on the cranks. They are just pressed in place, like the roller in the picture above.

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          • #50
            No problem David. Ultimately this looks like a good solution. The 3D parts were done in freecad that you can download for free and from there export into a format as needed. Not sure what material that is. Medium softness would be good to reduce the slippage.
            Here is the info on what material was for the pinch rollers:
            The film rollers and pinch rollers were printed in Shapeways' frosted detail plastic, as this gives a good smooth surface for gripping the film edges. First version in white standard nylon slipped more. The pinch rollers use bearing races so they can rotate freely. The film rollers fit steppers with a 5mm D shaped shaft. A little bit of electrical tape was used on the shaft to make a tight fit.
            These beams were used for idler arms and some other mounting assemblies:
            https://www.amazon.com/MakerBeam-200...dp/B01LYO8FAE/

            Looks like these bushings would fit. They are 14mm OD and the roller is 13.2mm.
            https://www.amazon.com/605-2RS-Groov...dp/B08JKG1N3D/
            Last edited by Stan Jelavic; October 14, 2021, 01:15 PM.

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            • #51
              From his list, 3D parts

              x Film Gate
              x Pi camera mount
              x Film roller on stepper motor
              x Pinch roller
              ? Film Idler rollers
              x Spool tables
              x Light box
              x Makerbeam end-stop (protects rubber band)

              Click image for larger version

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              Yes, I have Freecad installed, but have never used it. All the 3D parts are .fcstd. I was able to export to .stp. I tried to print gate #3 from the .stl. It is 2 parts that are connected so it was nice to be able to separate those in Fusion and create 2 .stls.

              My printer has been parked for several weeks. It was running great. So the print started, then had problems after several minutes. The displayed bed temp was 235deg C. just a little too warm, but cold to the touch. Checked the thermistor and it's ok. The bed's plug has a bad reputation, so tomorrow I'm going to cut off the plug and solder the connections. Hope that's the problem.

              I'll post the .stps so no one else needs to install Freecad. They can be inspected with Window's 3dviewer as can .stls.

              motor pinch-roller.zip

              I'm guessing you want the Pinch & Motor roller, maybe others printed or modified?

              Still I would feel better about a rubber roller as one of the two parts pinching.

              I have only experience with these filaments:
              PLA Very easy to work with. Low impact but high tensile strength. Vulnerable to sunlight and heat.
              PetG More difficult to dial in printer settings. Heat resistant, stronger than ABS with no toxic vapors.
              TPU Flexible, no impact breakage. More traction than PLA or PetG.

              For a textured surface, I have used wood fiber embedded PLA. Prints feel a bit rough like fine sandpaper.

              But how strong do these parts need to be?

              The surface texture could be achieved by coating with any paint mixed with sand. Or with "Flex Seal" or "Plasti Dip" for a rubberized surface.

              Just a thought.

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              • #52
                Thanks for converting the parts David. In a long run I have a concern with the rubber rollers because they touch the image area of the film and could damage it. Maybe I am too paranoid but anyways that is one of my concerns.
                I noticed that Shapeways also offer TPU. Here is the description:

                A rubber-like thermoplastic elastomeric material with high flexibility and functionality.

                This looks promising because it is grooved and flexible at the same time.

                FUD - frosted ultra detail plastic used in Kinograph is not available in Shapeways online quote. Perhaps they offer it as a custom finish.
                At this point I would like to complete the rubber roller test and make sure it can sync the film frames and then perhaps try the Kinograph type rollers.
                BTW, received the 128 step stepper controller and will give it a try next week some time.

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                • #53
                  Still busy with the roller mechanics. It is a bit challenging but will get there eventually. In the meantime received the stepper controller and here is what I plan to do with it.
                  Click image for larger version

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                  This removes most of the Wolverine vital components out of the picture. If the controller works out ok I will then revise the Hawkeye board and add the screw terminal there in place of the Wolverine PS connector plus the 12V plug.

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                  • #54
                    Sounds like you have a lot of work ahead Stan, good luck.

                    Well after a lot of testing on my printer, the mother board is bad, but only the part that regulates the print bed temperature. I'm happy to find it still available and only $29! Just 6 weeks to get here with Prime!

                    In the mean time I am able to use PLA as it does not require a hot printing surface. I've printed the Motor and Pinch rollers several times now and have decided to modify them. Small parts with cantilevered surfaces, means using support structures. Removing those supports is damaging the edges where the roller contacts the film. I'm going to break the motor roller into two parts and the pinch roller needs a wider hole, from 13.2 to 14mm. I ordered those bearings.

                    I do have some TPU. I don't remember if it needs a heated bed. It would better used for the Pinch roller. PLA on film has NO traction, very slick.

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                    • #55
                      Thank you David, luck is needed here, at least some luck and a prayer or two. Another alternative to TPU is to do the roller body in PLA and then slide a rubber ring over it. Leave the flanges long enough so that the two rollers are interlocked. The disadvantage is that this contacts the film image surface.

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                      • #56
                        This should help!

                        Click image for larger version

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                        I'm having more success with printing as I go. I was able to print A TPU pinch roller. It has less traction than I'd like, less than the rubber bands I used on the Capstan for the Hawkeye.

                        Maybe traction is not that important when there is pressure added? I'm going to assemble these parts and see how it goes. I have the motor from the Winait.


                        I did add rubber bands onto the PLA motor roller, one on each side. Small as they are they do stretch to fit with excellent traction, but without some kind of adhesive they will fall off with use. Finding the best size would be hard.

                        I'm going to try using O-rings instead. I have a large box of O-rings with several sizes.

                        As long as flat rollers keep rotating, I don't think they can damage a film. Starting and stopping might scratch?

                        Hope you have an old cartoon reel somewhere to be safe.

                        I think I'll redo the pinch roller to use the 0-rings and see how well it pulls the film.

                        If I get done before too long I'll send you test samples.

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                        • #57
                          4 leaf clovers, not one but two, that's got to do it
                          Maybe use the rollers with the flanges and then fit the rubber band over it. The flanges should prevent the bands from rolling off. Just an idea. I agree, teh rubber bands should not scratch the film unless there is a jam. Thanks for the samples offer. Appreciate that.
                          I have a pretty good idea on how to fi the idler roller with the rig I have. Will need some precision cutting. It is essentially an idler arm. Will try to post a few sketches tomorrow. It is a fork type with the roller shaft press fit into it and the roller runs freely on the shaft. This is just for initial testing and for the final design we can come up with something that can be 3D printed.

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                          • #58
                            Finished the pinch roller assembly today.
                            https://photos.app.goo.gl/L3f2yMBNCQ76iVoR9
                            Now as they say the proof is in the pudding.

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                            • #59
                              Your making progress! I've got some springs somewhere. Rubber bands aren't consistent.


                              My traction test. I'm still waiting for bearings. I printed placeholders that don't rotate as freely. With the real bearings, the pinch roller bolt can be tightened.

                              TPU pinchroller



                              PLA Motorroller (with o-rings) and pinchroller.



                              Quick setup.



                              Closeup video of the motor (with o-rings) and pinch.

                              https://drive.google.com/file/d/19gX...ew?usp=sharing

                              Small stuff todo. One of the o-rings sits a bit high. Need to widen the groove.

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                              • #60
                                You are making a good progress as well David.
                                I got a set of springs here:
                                https://www.amazon.com/gp/product/B076XKY3JM/

                                Tried the new rig today and it works. The performance is about the same as with the cogged wheel.
                                https://drive.google.com/file/d/10Ts...ew?usp=sharing

                                So, generally the setup with rubber rollers does work. The film does not slip off the rollers and the pinch force is not excessive at all.
                                The test clip is an old R8 film that I bought for a few bucks to be used for testing.

                                At this stage I plan swap the Wolverine stepper controller with the new controller that I got from Amazon.
                                https://www.amazon.com/gp/product/B075HBJP51/

                                And.... that is where I am.

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