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Pushing shaft through a Mabuchi motor

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  • Pushing shaft through a Mabuchi motor

    *EDIT* Once in a while it is handy to turn a can-drive motor into an endbell-drive, and vice-versa. Just pressing the shaft through an assembled motor is almost always going to end in tears...and a non-functioning motor. There IS a process by which this can be accomplished with an almost perfect record of success, ending up with a "reversed" motor that performs just like it did before you monkeyed with it. *EDIT*

    Hopefully someone here can help jog my memory. We used to do this all the time for our club's SOVREN spec cars, but I haven't done one in over 12 years now.

    I'm trying to push the motor shaft through a Ninco NC-1 (standard RTR Mabuchi can/endbell) to reverse which way the drive comes out. Standard is through the can end, I need it through the endbell end.

    Turns out that in my absence from slotting my old mentors, Rocky Russo and Larry Shepard, have passed away. I'm pretty sure it was Rocky who got me squared away the first time with this operation.

    Many many thanks in advance for any help,

    Scottrik
    Last edited by NOISY MUSE; 04-06-2017, 06:38 PM.

  • #2
    Personally, I wouldn't loosen the shaft in an armature but I would think heat and a series of light hammer blows would do it.

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    • #3
      It really doesn't "loosen" the shaft, there remains PLENTY of friction to hold it. SOME folks had luck SOME of the time "tapping" the shaft through, but we'd gotten to where we had 100% success. I DO know the motor had to be disassembled. I THINK we used a press, though we may have held them apart and tapped the shaft through. I honestly can't remember.

      Scottrik
      Last edited by NOISY MUSE; 04-06-2017, 06:43 PM.

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      • #4
        Try...

        Try contacting Ed at HO Race Pro. I seem to remember Ed doing something like that for some of his creations.

        Scott

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        • #5
          If you want to convert an endbell drive motor to can drive you could use a gear press. Going the other way is more risky because there is a self centering bearing in the endbell that is likely to be damaged. The possibility of moving the commutator closer to the stacks has already been noted in an earlier post.
          You could also get a M/T MT-1 motor from a supplier like Slot Car Corner, those are the same spec as a NC-1, but they are double ended. Now there is also the SCC Classic Tuna Motor 16K, which is half way in power between a NC-1 and a Scalextric "black stripe" FC-130.

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          • #6
            If you really must do this, and are required to use an NC1, you really must remove the armature. Trying to accomplish this procedure with the arm in the can, will likely damage the endbell bushing/housing, and, the brush assembly.

            So, with the armature removed,.....make a 3/8 to 1/2 inch block, with a hole drilled through to just accept the motor shaft...place this over the motor shaft on the comm end, .....place this assembly in a vice (align well), and slowly!! try to ease the shaft along. This has/does work, but success is not 100%, as the relatively soft comm blanks in all commonly used plastic car motors have a tendency to distort easily.........Good Luck!!

            If you are not required to use the Ninco NC1, there are several motors of similar performance, that have double ended motor shafts........much less stress .
            Both the MT-1 and the Dart/BWA motors, have similar performance to the NC1, and will pop right in.

            Cheers
            Chris Walker

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            • #7
              HA!!

              SUCCESS!!

              I knew if I just dove in it would come back. I knew that just pushing the comm through was a non-starter.

              Found a motor of unknown provenance and used it as my crash test dummy. Opened it up (seems like that process was easier...probably found a "secret" that has been forgotten) and had a look. As soon as I looked at the armature/comm assembly it all came back to me. The key is the brass bushing that locates the armature within the magnets. Measure the length from the bearing face of this brass bush to the top of the comm so you can duplicate this when you're done pressing.

              Use a gear puller to pull the brass bush back to about where you want it (fine-tuning will be done using this piece later) then put the comm into my home-made press (the Ninco press/puller I had didn't have enough stroke) that is a Harbor Freight C-clamp with the swivel removed (leaving a dimpled threaded shaft...the dimple is critical to keep everything centered) and a hole drilled through the anvil portion of the clamp. Press the comm slowly down the shaft, checking measurements. It kind of scoots in "pops" so it's hard to get precise. When you're pretty close to the desired measurement, either plus or minus, you can either pull or press the brass bush to exactly the measurement you want as it slides more smoothly AND is less prone to damage.

              Applied power from a 12v power supply and VIOLA!!

              It took as long or longer to type this than it will actually take me to do my proper motor! I knew we'd gotten to where it was quick, easy and reliable to do this.

              Scott

              **EDIT** I just did my NC-1...right at five minutes including unsoldering the leads and soldering them back on. Could do it with the leads in place, but easier without. It's out running on the power supply now seating the brushes.
              Last edited by NOISY MUSE; 04-06-2017, 12:36 PM.

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              • #8
                Good to see you managed this. We used to do this all the time.I made up a piece of shaft that was drilled out to the correct depth to hold the commutator and the laminations rested on the end of the shaft and the armature shaft could be then driven thru the laminations and commutator. We did this to use Can drive motors in Scalex cars.

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                • #9
                  Attached a couple pictures. First are the tools I used to push the shaft through. A commercially available puller and a press I made from a cheap Harbor Freight C-clamp probably 15 years ago. I've done another one of these since that I cut a slot into the anvil of a C-clamp.

                  The chassis shown is what we were building 12-15 years ago for our SOVREN (vintage '50-60's non-magnet cars) club cars. This is one I did for a Pink Kar Ferrari 250GTO that has been repainted as the Mecom-owned car Roger Penske drove in the Road America 500 (1964?). The chassis we used was readily available front-motor chassis from the MRRC Cobra. I dug one from my stash of about a half-dozen...wish I could get more. The chassis was easily cut and in this case lengthened 1/10" using a piece of styrene strip as a spacer and two lengths of 3/16" styrene tubing in the channels molded into the sides of the chassis to serve as stiffeners. Powered by NC-1 (or in this case the identical spec Cartrix TX-1), BWA wheels and (I think) Indygrip silicone tires on the back. Slot.it axles and gearing. The motor uses a FLY driveshaft joining spring and a length of .078 (2mm) music wire for the driveshaft.

                  Now if I could just remember what we were doing for driveshaft bushings. I almost think it was a brass axle bushing with a short length of 3/32 OD brass tubing soldered in.

                  *EDIT* Further analysis shows that is EXACTLY how the driveshaft bushing was made. *EDIT*

                  This chassis probably has a little too much brass cut and fitted in for weight, the car weighs in at about 95 grams, could probably stand to lose 15-20 grams for an NC-1 powered car.

                  Scott
                  Last edited by NOISY MUSE; 04-06-2017, 06:41 PM.

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                  • #10
                    Nifty!

                    Such a useful piece of info, I'm gonna Stick it here for others who may be faced with the same challenge in the future.

                    Do you think the working title should be changed? If so, you can edit that (Edit/Go Advanced/Title) in your initial post.

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                    • #11
                      For the G clamp it is easier to grind a slot with a dremel than to drill an accurate hole. Just saying...

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                      • #12
                        As I describe in one of the later posts...I have a C-clamp where I did exactly that when I needed to change a pinion on one of my plane motors and couldn't find the one I had.

                        That said, my preference for this task would still be to have the hole. It's just a nicer tool.

                        I don't exactly remember how I drilled the hole in this one, but it couldn't have been TOO difficult. Looking at it I think I found the center of the anvil (not a difficult proposition) then used one of my drill presses to create the hole, probably backed up with a piece of scrap wood block.

                        Scott
                        Last edited by NOISY MUSE; 04-06-2017, 07:50 PM. Reason: Added picture

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