CHEAP 3 - 1 REDUCTION GEARBOXES

[Dietrich]

Hello Guys :~
FIRSTLY....sorry this was meant to be a 'Preview NOT a Post'....as it may need a bit of tweeking
Let me start out by saying that this is NOT my original idea.....but I think that it is worth while rewriting and putting it on the Forum as it works so well, is relatively easy and if you have upgraded to metal gearboxes costs NOTHING
All my'Construction Example' pictures are of PLASTIC gearboxes simply because I have already upgraded my metal ones and I was too lazy to take them out of the Tanks and dismantle them Do NOT use a totally plastic gear box as the teeth are NOT strong enough and you will strip the teeth lower down the ratios towards the final drive.
Having said that the single plastic gear that we ARE going to use is connected to the motor drive pinion and is under little to no stress at all as it is so 'High- Up in the gear drive train,and so WILL work perfectly !!
Here is the two gearboxes with the drive motors removed but assembled ready to convert.
http://i690.photobucket.com/albums/vv26 ... ure012.jpg" onclick="window.open(this.href);return false;

http://i690.photobucket.com/albums/vv26 ... e014-1.jpg" onclick="window.open(this.href);return false;
Remove the cross-bracing screws and then remove the two bottom screws that hold the two halves of the gearbox together.
http://i690.photobucket.com/albums/vv26 ... ure038.jpg" onclick="window.open(this.href);return false;
I am using a screwdriver tip to point at the top cross bracing screw hole, this is the hole that we are going to enlarge in both metal side-plates to take a gear wheel bar bushing. Completely dismantle ONE gearbox at a time so that parts do not get confused, then with the two metal gear mounting plates bolt them together so that all the holes line up perfectly to avoid any misalignment issues.
http://i690.photobucket.com/albums/vv26 ... e074-1.jpg" onclick="window.open(this.href);return false;
The red piece of plastic again points to the cross-bracing hole that we are going to enlarge, then carefully drill it out to 6mm diameter.
http://i690.photobucket.com/albums/vv26 ... ure045.jpg" onclick="window.open(this.href);return false;
While the two halves are clamped together drill a new 3mm hole where I am pointing with the red wire.This is a new position to add the cross-bracing rod that we have already removed. Now glue two of the white plastic bushes into the 6mm holes making sure that you place the spacer/running face on the correct side of the metal support :~
http://i690.photobucket.com/albums/vv26 ... ure047.jpg" onclick="window.open(this.href);return false;
Now using a plastic 'First Gear' wheel ( the one that was originally driven by the motor pinion ) cut the circular spacing piece off the gear and add it back onto the opposite side of the gear so that it sits flush up against the small gear.
http://i690.photobucket.com/albums/vv26 ... ure075.jpg" onclick="window.open(this.href);return false;
http://i690.photobucket.com/albums/vv26 ... ure076.jpg" onclick="window.open(this.href);return false;

The Drive Pinion now needs the gear to be pushed off its splines and then reversed and replaced back onto its splines, this is because the gears will be slightly reorganised when reassembled with the 'New' first gear.
http://i690.photobucket.com/albums/vv26 ... ure059.jpg" onclick="window.open(this.href);return false;
Try to make sure that it does line up with the splines so that it is easier to put back and reduces the chance of it having to 'cut' new splines in itself and so weakening its 'GRIP'........At this point I would add that just to be on the safe side I glued my gear when I replaced it AND drilled a small hole through the gear collar and shaft to add a securing dowel pin, just to be certain. Please note that the pin will need to be filed COMPLETELY flat to the gear collar face,so that it does not catch or foul on another gears teeth that run very close to the collar.
The last thing to do is to push the brass drive pinion down the drive shaft so that it almost touches the motor so that it drives the 'New' first gear and does not foul the old one.
http://i690.photobucket.com/albums/vv26 ... e140-1.jpg" onclick="window.open(this.href);return false;
Make sure that as you do this that you support the other end of the shaft and that you are NOT just pushing against the case! The best method is to use a vice and a small socket to press the pinion down, (but obviously protect the jaws from damaging the drive shaft)
Then simply reassemble the gear boxes as per this photograph, you may have to tweak the motor mounting holes and turn them slightly into slots so that the gears can be correctly aligned,not too tight or it will be stiff to turn and will be very noisy and not too loose or you risk it jumping or slipping gears.
http://i690.photobucket.com/albums/vv26 ... e069-1.jpg" onclick="window.open(this.href);return false;
Fitted in Tiger and working
http://i690.photobucket.com/albums/vv26 ... G_4597.jpg" onclick="window.open(this.href);return false;
You can replace the standard pinion gear of 10 teeth with an aftermarket 13 teeth gear and this will apparently avoid you having to tweak / alter the motor mounts on the gearbox plates.

[Miggers]

Hiya Dietrich.

You also need to glue up the slipper clutch in the additional gear you fit.

I've done this mod with the totally plastic 'boxes(my Tiger is an all original 2007 MY S&S)and with standard tracks,sprockets and idlers,it drives extremely well,so well infact that the tracks
are full of mud.

The Tx mod is well worth doing too.
It's posted up on here by BREL and is an excellent article.

Mark

[Dietrich]

Hello Mark, :~
Thank you for pointing that out, some of the plastic gearbox come with a 'First' gear that is in two parts,with one piece sitting inside the other and held in place by teeth.This allows the engine to force these teeth to 'Slip over' each other rather than 'stall' the motor and to possibly burn out a control board.
If you have these 'slipper clutches' in the gear then you can clean easily remove this function by cleaning them of all the grease and then epoxy glue them in place,or heat a pin and use it to make a hole through the two parts of the gear.Then glue the pin in place and trim off both ends so that it acts as a 'dowel pin' BUT be careful that none of it protrudes and does not rub against any other gears.
Regards, :~
Alb.

[BREL]

Hiya Dietrich.
The Tx mod is well worth doing too.
It's posted up on here by BREL and is an excellent article.

Mark

Mark, thanks for the kind words on my TX mod article which can be found here
http://www.rctankwarfare.co.uk/forums/v ... =38&t=3826" onclick="window.open(this.href);return false;

[Miggers]

No problem Stew.

I think it a simple, highly effective and worthwhile mod that makes a tank much easier and nicer to drive.
Your article is well written and well documented by the pictures,simply followed and gives
great results.
To the new owner of say,a Tiger,it's one of those essential mods such as the main gun length,
mantlet,pistol port and cupola.

I've never seen it anywhere else and can't recommend it highly enough.

Mark

[dadio]

thanks for shareing this,i'd just got a set of steel geared boxes with standaed ratio's and was kicking myself for not spending more on the reduced ratio ones when i saw this .really transforms the tank and all it takes is a little time.