Can a gear slip one way and not the other ?

[wibblywobbly]

I had two sets of those gearboxes and they both went the same way. The frames were made of really soft metal and they twisted near to the final drive shaft, which allowed the gears to slip. I spent many an evening trying to get them working but in the end I junked both sets.

The real solution is, when they are new, to beef up the frames so that they can't bend.

The gears were also slipping on the shafts. I resolved this by securing the gear in place with blue tack (that sticky blue stuff that you use to hold paper notes onto walls etc), and then removing the grub screw. I then drilled through the grub screw hole and into the shaft, creating a shallow hole.

Then, when the grub screw was put back in it was half in the gear, and half in the shaft. A few drops of threadlock on the threads and it would stay where it was.

The other, very permanent option, is to use 2 part metal glue on the shaft, slide the gear over it, and quickly insert and tighten the grub screw before it cures.

They were super quiet gearboxes, and great reduction gears, but running in a heavy tank when there was resistance on the tracks eg grass, pushed them beyond their out of the box strength.

RobG

[MichaelC]

I had two sets of those gearboxes and they both went the same way. The frames were made of really soft metal and they twisted near to the final drive shaft, which allowed the gears to slip. I spent many an evening trying to get them working but in the end I junked both sets.RobG

Hmmm that's depressing. Torro Shop still carries them but it will be 100 euro to get it over the pond so I will have to work on this one for the time being. I have used washers as shim/spacer and will see how it goes today. Penny might be too much but we should see. Of course we don't use them anymore so a dim might actually be a better option for me.

Unfortunately I custom fitted this gear set so in order to switch I will have to completely we do the mount on the lower hull etc which might be quite the effort.

Thanks for the info (again) as this will be my last kick at this can. Need a complete overhaul if this is not satisfactory.

MichaelC.

[ALPHA]

Just another thought Michael...if it is the gear that is actually not making contact and not the axle junction... file the bushing hole towards the secondary gear a little then solder the axle bushing to the frame (just to take up the gap)....JB weld might work too


ALPHA

PS. If there is a good machine shop in your area...you might be able to have them "shot peen" the frames...compressing the molecules of the metal helps stiffen it

[971wright]

Alpha if you have seen these gears the metal is so soft its a joke , no amount a shot peening would work harden the metal even age hardening would take at least 100years . its crap aluminium like thick foil . the only chance is to put a steel outer on.

regards pete

P.S. you can also solder the gears on the final drive this works. swop the drive shafts around so they have more support from the long side.

[ALPHA]

Alpha if you have seen these gears the metal is so soft its a joke , no amount a shot peening would work harden the metal even age hardening would take at least 100years . its crap aluminium like thick foil . the only chance is to put a steel outer on.

regards pete

P.S. you can also solder the gears on the final drive this works. swop the drive shafts around so they have more support from the long side.

From my personal view... I never liked brass as a primary metal for gears....Bronze would even be better....with that said..it's the reason I don't own any gearboxes with brass gears...no matter who makes them....the Asiatams that Sassgrunt allowed me to photograph have steel cages...but still doesn't make a difference IMO..brass is too soft...under load can shear too easily
If the cages on this one is aluminum then that's too thin of a gauge to be using ...that info is important I think......Thanks for that addition.... it really does make a difference ....If worse came to worse for Michael and he didn't want to spend a bundle on new gearboxes... making new frames out of the same gauge ...but in steel ..... just hammer those aluminum suckers flat ...and use them as templates

ALPHA

[tomhugill]

From what I've seen brass gears aren't usually an issue. Tamiya gearboxes use them and they're great, the low profile asiatams I've used in my panthers have also been really good. Brass shafts aren't so clever though! If your shafts flexing there's not masses you can do to fix it.

[ALPHA]

From what I've seen brass gears aren't usually an issue. Tamiya gearboxes use them and they're great, the low profile asiatams I've used in my panthers have also been really good. Brass shafts aren't so clever though! If your shafts flexing there's not masses you can do to fix it.

Yeah...brass gears are pretty common .... seen it used on many a pinion... but still ...steel is for real ...With that said though...I wish they made brass pinions for micro motors.... have a set of Radio Shack battle M1 abrams tanks...about 1/72nd scale... those nylon pinions aren't worth a heck of a lot...you can find them..but they always crack

ALPHA

[MichaelC]

Thanks guys. I went back to my workable solution. I move the final gear towards the middle of the frame and instead of driving off the outside secondary gear, I use the middle secondary gear (Green arrow) so there is more contact between the gears. I upgraded the motor to 400s so that there is more torque and higher RPM to compensate for it. I don't understand it but the middle secondary gear looks the same as the outside one but clearly it doesn't have the same torque and slow RPM in the gearset. Not the best running tank but at least it is moving vs just sitting there spinning until smoke starts to come out.

mato-5-1-gearboxes-for-mato-matorro-king-tiger-1729-p.jpg (42.44 KiB) Viewed 1022 times

pete, the gear is not slipping off the drive shaft so soldering that is not going to help. ALPHA, I don't think I have the skill/tools to move the actual axle but I think that might work in this case.

[ALPHA]

Thanks guys. I went back to my workable solution. I move the final gear towards the middle of the frame and instead of driving off the outside secondary gear, I use the middle secondary gear (Green arrow) so there is more contact between the gears. I upgraded the motor to 400s so that there is more torque and higher RPM to compensate for it. I don't understand it but the middle secondary gear looks the same as the outside one but clearly it doesn't have the same torque and slow RPM in the gearset. Not the best running tank but at least it is moving vs just sitting there spinning until smoke starts to come out.

mato-5-1-gearboxes-for-mato-matorro-king-tiger-1729-p.jpg

pete, the gear is not slipping off the drive shaft so soldering that is not going to help. ALPHA, I don't think I have the skill/tools to move the actual axle but I think that might work in this case.

GOOD O Michael!....one thing good about fielding suggestions.... it sometimes help clear the path of troubleshoots to get to the final solution

Glad to hear you sorted it out If I ever do one of these tanks... I'll be sure to contact you

ALPHA

[blimp]

Hello Michael , will a flanged bearing ( behind the sprocket ) support the end of the shaft and stop it flexing ?