Drive Sprockets - Murrells Models

The drive hubs I used on the Sdkfz250/5 & Kettenkrad are no longer available so this is my alternative, having a two part hub makes this quite expensive, from ActiveRobots parts numbers:

This is the half of the sprocket nearest the body, we need to remove the center moulding

I have used a dremel with a circular saw blade to cut around the moulding and then snapped it off

Get it as flat as you can

Now for the other side, this needs to be reduced to about 2 or 3mm in height, so that the hex hub sits over it

Used the Dremel again to saw some off

Down to the correct height

So the hex hub sits on it with no gaps underneath it, this help so centralise the hub for drilling the 4 through holes

The hex hub still moves about abit so to align it exactly centraly I used a small bearing and the screw in the hub to clamp the hub in place for drilling and to hold it central in the sprocket

Clamped up ready to drill with a 4mm drill

First hole drilled, stick a bolt in it to keep the alignment in case the hex hub tries to move

4 holes drilled

Put the 4 bolts through into the D hub

My bolts were too long and had to be shortened

Now the centre screw & washer go in the outer half of the hub