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A Pinion Surprise !

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  • A Pinion Surprise !

    'Boy, scratch building is full of surprises and challenges. Personal latest example : right now, I am STUCK, due to a problem I've Never had. Completing the back end (motor bracket, motor, axle, bushings, crown gear, Pinion Gear), of a 'build. Everything is as it should be, except THE AXLE/GEARS WON'T TURN ! I mean, the binding is unreal. I've spent close to an hour taking things apart, and re-assembling them. Same problem. Lately, in addition to my main supplier, Slot Car Corner, I've been buying parts from another source, too. Their 9 and 10 Tooth pinions, are twice as long as the usual pinion gears. But, I used one on my previous build, I'm almost sure. I keep them, of course, in the same little "pinion gear container", as all other pinions, from Scalextric to Carrera plastic ones. But, man, I've mentally questioned myself, about "don't they look a little fatter than the other brass pinions ?" Anyway, I just decided to line up, back to back, a regular-length pinion, and a long pinion, both 9-tooth. It wasn't my imagination, after all : that long pinion, Is Larger In Diameter !! There Is My Binding Problem ! I need educating about a lotta Basic stuff, I see. I apparently assumed all 9 tooth pinions are a standard diameter. I'm gonna have to be more aware of things, as I spend my money, because I have made a Few mistakes, of late. I'll bet most of You hobbyist's, knew about differing pinions.

  • #2
    Gonna try to upload two photos of Gears
    Attached Files

    Comment


    • #3
      Post a picture, that may help.
      If you are using an inline slot it crown gear with a slot that the motor shaft rides in you need a 5.5mm diameter gear to get the proper gear mesh. You can also set the mesh using spacers and will allow you to cut the shaft and not rely on the motor shaft maintaining the mesh.
      Brad
      Ayton, ON Canada

      Comment


      • 6666hotrod
        6666hotrod commented
        Editing a comment
        Great points : Thanks !

    • #4
      Considering that those 2 pinions are from different sources they may also be a different pitch.

      HTH
      Randy
      Randy C
      Grindrod B.C.
      Canada

      Comment


      • #5
        looks like one might be a sidewinder gear.
        bill ,framingham ma

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        • #6
          The fact that those two pinions have different diameters with the same number of teeth means they have different 'pitch'. For a proper gear mesh you need to have the pinion gear and the gear it drives (crown gear or spur gear) to have the same pitch.

          Pitch is defined in English measure as teeth-per-inch. At least for the small gears used in slotcars. Common pitches for slotcar gears are 32, 48 and 64 teeth per inch. In general more teeth per inch yields better efficiency and smoother operation. But it also means the spacing of the gears is more critical. And gears with more teeth-per-inch tend to be more expensive since the quality of the tooth form is more critical.

          I won't get into how gear pitch is defined or calculated. All you really need to know is you shouldn't mix gears with different pitches. Check the gear pitch when purchasing. If it isn't listed you might want to shop elsewhere.
          Ed Bianchi
          York Pennsylvania USA

          Comment


          • chrisguyw
            chrisguyw commented
            Editing a comment
            Which Slotcars would you commonly see using 32P gears ???

          • HO RacePro
            HO RacePro commented
            Editing a comment
            Hmm... After looking a bit online it seems that 32 pitch is common for RC cars, but not slotcars. I also see that some folks are offering 72 pitch gears.

          • chrisguyw
            chrisguyw commented
            Editing a comment
            I have not seen a slotcar that uses 32 pitch gears,...........the "pitch" variations used for slotcars are......, .5 module (roughly 50P), for the current plastic 1/32 cars from Slot-it,NSR, Scalextric, Scaleauto, etc. etc..... 48P for vintage, D3/retro cars, and some lower level commercial track cars,.... 64P, 72P and 80P for the higher end commercial track cars.

            All the 48P, 64P, 72P, 80P gears (both pinions and Spurs and Crowns) are "true pitch" in that each tooth count has a slightly different diameter,........it is only the .5 module gears (1/32 plastic cars) that offer different tooth counts for a given diameter.
            Last edited by chrisguyw; February 21, 2022, 05:22 PM.

        • #7
          With the gears used for slot cars pitch can go out of the window. In the case of the spur gears that are used with many 1/32nd scale cars there are only two different diameters with several different tooth counts being available for each diameter. That means that the pitch can't be correct in most cases, but in fact the gears mesh well. The problem with 1/32 sidewinder cars is that the motor can't be moved to adjust the mesh, so the gear diameters have to be matched up. Most sidewinder pinions are 6.5 mm in diameter. The spur gears can be 18 or 19 mm in diameter. The trick that is used to get the gears to mesh well is that the teeth on the spur gears are shaped so that the pitch diameter matches up. The teeth on the gears are not shaped as they would be with regular standard gears.

          Comment


          • HO RacePro
            HO RacePro commented
            Editing a comment
            RichD knows whereof he speaks. Myself, I wonder a lot about the sidewinder tooth design tweaks needed to keep the axle centerlines constant for different ratios. The classic involute gear tooth shape allows the gear teeth to roll against each other rather than sliding. I suspect some performance is traded away when reworking the tooth design. I'd love to see some analysis and/or performance data addressing this.

            Ed Bianchi

        • #8
          You don't say if you are building and inline, side or angelwinder car, also not sure if you using a pre-manufactured plastic motor mount in your build, or custom parts. With Slot.It motor pods, this reference chart can come in handy.

          Click image for larger version  Name:	slot it gear.jpg Views:	0 Size:	134.0 KB ID:	151022
          "I don't make mistakes. I make prophecies which immediately turn out to be wrong "
          "And that just shows you how important the car is in Formula One Racing"

          Murray Walker

          Comment


          • 6666hotrod
            6666hotrod commented
            Editing a comment
            What I am building is basically a Harry Wise SHOWDOWN inline chassis !

        • #9
          Not sure what you are setting up, but
          If you are using 1/32 gears for that car (3/32 axel), inline, the shaft of the motor has to ride in the groove of the axel gear,. You need to use inline gears.
          I suggest slot it gears, gear pitch match for pinion and axel gears. the pinion has to be inline 5.5mm and inline grown gears.

          FYI. there are 5.5mm pinions for inline, use with inline grown gears. 6.5mm pinions for sidewinder with straight cut sidewinder crowns, and 6.5mm pinions with angle winder crowns.
          Last edited by lance; February 22, 2022, 12:38 AM.
          Lance Sofa racer, SA TX by way of Hawaii

          Comment


          • #10
            Some of the older slot cars had extra long pinion gear! Because of the motors are mounted further away from the crown gear because of the hing pin in the chassis, which the pinion had to reach over to mesh with the crown gear! The COX
            La Cucaracha is a good example of this. Just a little on vintage 1/24 car's I learnt when I tried to put a larger pinion on it ,
            Cheers,
            John.

            Comment


            • 6666hotrod
              6666hotrod commented
              Editing a comment
              Thanks : that's good information, to store in the Knowledge Bank !
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