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OpenSlotCar Design

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  • #31
    Ah, that certainly could be. One would think the screw still had good contact with the braid, though. Soldering the braid to the wire, or just using the raw wire is a solution, of course, but being able to change braid without soldering or replacing wire is a good thing, if possible.


    • #32
      Hello. I'm new to 3D printing. Soon I'm trying. For now successful only for rims. Now I'm trying to make a body. The rims are all my projects.


      • #33
        Hello again! Several photos from me.

        These are my first attempts. I still have printing problems, but I hope to get better results soon.


        • #34
          Great start!


          • #35
            Those prints look good. With an FDM printer, there is going to be handwork to make the prints into something nice at the end no matter how much you fiddle with the printer.

            A few tips I could give you, for the car bodies (not the van) try printing with the model pointed straight up. So the front bumper would be pointed towards the ceiling. The details on the rear face and the front face may suffer a bit, but the rest of the car will look like a million bucks. I've experimented a little with breaking the body model up into parts so I can print them in different orientations. If you can just cut off the front 6 mm off of the body and the rear 6mm and print them in "normal" orientation, then print the rest of the body in a vertical orientation, that would be optimal.

            The VW van wouldn't be as good to do this with, because of how large and flat the front and rear end are. That overall geometry lends itself to printing as you have done here.

            I print the bodies for the car I've been working on on their sides. The body has a very flat side, so it sticks to the printer bed well. I end up with 10x the weight of the body as support inside the body, but the final part is pretty good.


            • #36

              kit from OpenSlotCarDesign.
              runs really good, lap times under 10 seconds.
              files for printing will be available for download. body is nice, chassis works good.


              • #37
                Thanks for posting the write up. It's been a while since I've looked at SCI. The new forum software seems pretty good.
                Did you end up using any of the lead weights or did you decide the car was faster without them?


                • #38
                  Originally posted by Cdub View Post
                  Thanks for posting the write up. It's been a while since I've looked at SCI. The new forum software seems pretty good.
                  Did you end up using any of the lead weights or did you decide the car was faster without them?
                  i did not use any of the lead weights.
                  if the car is properly designed and built, on my track at least, you will not need any. this is a smooth wood track, things are different on segment plastic track.


                  • #39
                    I've been working on and off on my 3D Printed "OpenSlotCar" design for a while now. I have two areas that I want to improve before I turn the files loose. One of them is the setscrew wheels (the other is the process for molding the tires).

                    I had a bit of a break through on the wheels that I'm quite happy with.

                    The original wheels were just 3D printed with a "cross drilled" hole for a set screw. I advised threading the hole with a tap to reduce the risk of stripping the plastic out with the setscrew.

                    These wheels worked okay, but could only be tightened and loosened around a dozen times at most before the plastic gave up. It was also difficult to get them tight enough not to slip but not strip them.

                    The solution I came up with is very simple, and I believe would be useful for many other 3D printed couplings. Essentially, I took the wheel model and added a pocket that was sized to press fit a piece of 6mm OD brass tubing. I pressed the tubing in, then cross drilled it with a drill and tapped the combined plastic/brass hole.

                    This hoop of brass gives the screw a sliver of metal to grab onto and yields a much stronger joint than just the plastic threads.

                    Step 1: cut the tubing to length.

                    Step 2: Hammer the piece of tubing into place

                    Step 3: Put the wheel in a vice

                    Step 4: Drill out the hole

                    Step 5: Tap the threads. I'm using M3 setscrews, so an M3x0.5 tap.

                    Step 6: Wheels fitted to a scrap of 2mm OD shaft.

                    This system provides a connection that can be really tightened down hard with a hex driver and grips the axle hard enough that it is very difficult to twist or pull the wheel straight off with your hands.