Final Reduction Gearbox and Cover

The splined input shaft, gear cluster and gear box end cover.

The cover was machined in the lathe to maintain the tight tolerance required

This is the final drive gear being machined from K1045 steel. It has 73 teeth 1.5 module. This gear gets bolted to the hub of the drive sprocket.

Here is the drive sprocket, final drive gear and drive pinion attached to the steering brake drum and drive clutch spline which receives the clutch spider.







The drive pinion installed in the transmission and the final drive gear with the sprocket removed. The cover plate mount is also in position.

The inside profile of the clamp plate has been finished. About to cut the final shape.

Behind is the transmission mount plate, then the clamp plate (from above) and the gear cover partially fabricated using oxy welding and monel filler wire. This was done for strength so that it did not fall apart on subsequent operations. The mounting plate and ribs (shown later) were brazed on.

Left and right gear covers. Showing right hand cover (on left) before fabrication.

Here is the cover in place. Also seen here is the drive hub with studs where the drive sprocket attaches.

The completed cover temporarily fixed with cap screws to the transmission. These screws will be replaced with hex headed 3mm bolts.

Note the cap bolted to the outside of the cover. This houses the outer pinion ball-race.

Gear box

This shows one of the eight gears being hobbed by the system described in Model Engineers Work Shop magazine of October
2003. The 90 to 1 rotary table is driven by a stepper motor by 2 to 1 tooth belt. The hob shaft drives an encoder by tooth belt to generate 18,000 pulses per revolution.Synchronism is achieved by
three numbered digital switches. The number of teeth required is dialled, the table is set to cut parallel teeth, the gear blank of correct diameter is fixed to the rotary table by a morse taper arbor. The teeth are cut in one pass


This is the gear cluster mounted in the case before the bottom was welded in place. The gear at the top is low gear which meshes with the reverse gear idler cluster.







This is the final drive shaft with steering clutches and bevel gear.
The bevel gear and pinion shaft were salvaged from a disk sander .




This is the gearbox cluster and spline shaft. The spline shaft extends through the rear of the transmission as the power take-off. The cluster shows from the left, low gear, top gear in the centre and second gear on the right.


This is half of the ball cage for the throw-out bearing (part of the steering clutch) being machined from brass. Two sides are riveted together capturing the 16 1/8" balls. There is one for each clutch.







The completed thrust bearings.