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  • Shapeways Gears

    I was on the Shapeways website just now, seeing if I could find a specific type of spur gear. It had occurred to me that 3D printing might be a great way to create custom plastic gears.

    So I first entered "48t 64p spur gear" and then "48 tooth 64 pitch spur gear" in the "mechanical parts" category and in each case got 300-plus results, none of which were 48 tooth 64 pitch spur gears, or rarely anything even close.

    So one, the search engine for Shapeways ain't all that great. Two, there are no standard naming conventions for parts on Shapeways. And three, slotcar gear designs seem to be absent from Shapeways.

    Is anyone aware of a source for printed slotcar gears? I still think this is a likely way to make custom gears.

    In the meantime I have ordered a Sonic brand aluminum Tri-Light 48t 64p spur gear from Professor Motor. It is considered a drag racing part, and I have a concern it will not last very long being driven by a metal pinion gear. TBD.

    Ed Bianchi


  • #2
    Doesn't our own Snapfit print gears?

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    • #3
      Vas ist das Snapfit?

      No luck Googling it.

      Ed Bianchi

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      • #4
        I made a mistake, snapfit is his online auction house handle, on here he is something else.

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        • #5
          On here he is eagle racing: http://www.slotcarillustrated.com/po...9-eagle-racing
          Last edited by NicoRosberg.; 06-02-2019, 11:57 PM.

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          • #6
            Hi Ed,

            Robert, aka: "Eagle Racing" here on SCI, printed his own gears a while back. Look back in his thread of the same name and PM him for additional insight maybe.

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            • #7
              duplicate
              Last edited by chrisguyw; 06-06-2019, 06:50 AM. Reason: duplicate

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              • #8
                Originally posted by HO RacePro View Post
                I

                In the meantime I have ordered a Sonic brand aluminum Tri-Light 48t 64p spur gear from Professor Motor. It is considered a drag racing part, and I have a concern it will not last very long being driven by a metal pinion gear. TBD.

                Ed Bianchi
                Sonic produce some of the best made /accurate gears, available ,and are generally found on high end commercial track type cars. The quality is much better than the stuff typically used in the 1/32 hobby, and they have been producing them for many many years.....so, do not have any quality concerns.

                As most of the typical 1/32 spur gears (Slot-it,NSR, etc.) are also aluminum, longevity of the Sonic, will also not be an issue........the slightly finer pitch on the Sonic (64P) will obviously require a 64P pinion, and attention must be paid when setting the mesh, and ensuring an absolute minimum amount of flex in the motor box area.

                The only reason it is considered a drag racing part is because of the high tooth count/diameter, which requires larger dia. "drag" tires for clearance.......and typically, this gear would be driven by a motor (and steel pinion), with the motor being significantly more powerful than anything you would likely use.

                Cheers
                Chris Walker

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                • #9
                  Thank you Chris for the endorsement of Sonic gears!

                  As it turns out, in my application, the 48-tooth gear has just enough ground clearance with a conventional-size road-racing tire. The 20-tooth pinion gear I'll be using is steel, also by Sonic, so should be completely compatible. Good to know.

                  The Sonic Tri-Light spur gear has been lightened with cut-outs, and has a very narrow tooth face, which gives it a very low rotational inertia. Maybe not so important for a road-racing car, but certainly a plus for a dragster. (I suppose the third leg of the Tri-Light design is the aluminum material. It would make sense.)

                  My gear ratio works out to 2.4:1, which is significantly lower than is common for 1/32nd scale cars. I am hoping the fact the motor spec'd for this class of car is rated at 18k RPM will mean it'll have a high torque output, which might work well with the low gear ratio.

                  I've been experimenting with low gear ratios in my scratch-built IHSR cars, starting with 1:1 direct drive. Direct drive worked better than most folks expected, but was not competitive. My next iteration, with a 2:1 ratio, was able to out-run a few of the other cars in its class. Some handling tweaks might improve that.

                  So next I'll be giving 2.4:1 a try.

                  Why am I bothering with these low gear ratios? As always, I'm seeking an edge. Could be a waste of time and money, but running an unconventional gear ratio is potentially a way to break away from the pack.

                  Ed Bianchi
                  Last edited by HO RacePro; 06-07-2019, 05:21 AM.

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                  • #10
                    Thinking along the same lines, Ed. It will be interesting to see where we end up.

                    Al

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                    • #11
                      Originally posted by HO RacePro View Post
                      My gear ratio works out to 2.4:1, which is significantly lower than is common for 1/32nd scale cars. I am hoping the fact the motor spec'd for this class of car is rated at 18k RPM will mean it'll have a high torque output, which might work well with the low gear ratio.

                      Ed Bianchi
                      Hi Ed, Our local area clubs (comprising roughly 40/45 racers) run several classes for motors in the 14/18K range (both FF050 and 130 motors ) and ratios in the 2:3 to 2::5 range are the norm.....(this is for cars weighing in at no more than 65/70 gms, and magnet free). While acceleration, and, therefore braking do suffer a touch, the terminal speeds of these cars is such that ferocious braking is not required.

                      Additionally, if you look at the spec sheets for many of the proxies that run lower powered motors, ratios in the 2:3 to 2:5 range are more than common for the top cars.......again, assuming that running weights are less than 70gms, and that they are running traction magnet free.

                      Cheers
                      Chris Walker

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                      • #12
                        Further to Chris's point, at the end of the 1967 F1 Proxy, I graphed various parameters vs finishing position. One of the factors I looked at was "effective torque" :

                        (Motor spec torque X gear ratio)/ rear wheel/tire diameter

                        There was a decent correlation with lower effective torque > higher finish

                        Al

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                        • #13
                          The lower the effective torque is the easier the car will be to drive, you will feel more confident in pushing the car and your lap times will be more consistent. If you get carried away with the gears you car may not have enough acceleration and the car may never reach top speed. You would also have less brakes, but I run all of my cars with reduced brakes in any case. If I am given a choice I gear my cars at 2.5:1. With sidewinder gears it is harder to go lower than that. Many people think that if they are running on a twisty technical track with short straights they would be better off with a taller gear ratio, maybe greater than 3:1. I have not found that to be the case with non-magnet cars.
                          You can theorize all you want, it never hurts to experiment a little with motors, tire diameters and gear ratios.

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