Sequential 7+R speeds gearbox instructions

To start of I’d like to say that what made me design this gear box was the fact that since the 8448 there hasn’t really been any development as far as gear boxes are concerned. AS a matter of fact there is a large number of great MOCs that in the end mostly use the same well-known, rather clumsy (although very reliable) manual gear box. Because of its reliability I decided to use this very gear box as the base for my design.

The gearbox itself is a modified version of the one you can find in the 8448, but built studdless and with two extra speeds (6th y 7th)

But in order to make it work one more change is necessary: all the Axle Connector Ridged (6538/a/b) mist be substituted by Axle Connector Smooth (6538c)

Important note!!!
The Axle Connector Smooth has two rounded sides and two flat sides. It is very important that the internal pins of the Driving Ring (6539) coincide with the flat faces of the axle connector

Additionally the structure that contains the Changeover Catches (6641) is built

Both parts are joined taking care to make them mesh correctly

After that the structure that contains the rockers is built

The rockers are placed over the handles of the Changeover Catches

The rail that will accommodate the gear selector must be properly secured

The rubber used in the gear selector must be very tense

It is put in place sliding it in from one of the sides.
Once it is in place, the gears can already be changed sequentially, sliding the gear selector forwards and backwards, meshing one gear and unmeshing another

Reverse

Speed 1

Speed 2

Speed 3

Speed 4

Speed 5

Speed 6

Speed 7

If the Changeover Catches don’t move o don’t move smoothly too much friction has been introduced in the construction. Go over the moving parts of the gear box one by one and make sure they have the least possible friction.

What remains it is the part needed to move the selector little by little. This can be done in several ways. The system I used is bulky but reliable and relatively simple.

The long liftarm you can see in the last photo is what will later become the gear lever.

Add the supports for the selector

Finally the two self-centring devices (top and bottom)

The rubbers should be neither very tight nor very loose. If the teeth on the device don’t grip or let go the selector they are either too strong or too weak.

That’s it!!!

The gear box should now work correctly. By pulling the lever away from the gear box you gear up and by pulling it the other way you gear down.

A video with gearbox working:



Finally you can download instructions in PDF in the INSTRUCTIONS page and access to the Download folder



If you have any comments or questions, leave a comment!!!