The locomotive shop - 28xx no 2811 part 3
The crank pins have arrived and I've managed to escape to the workbrench for short periods over the last few days.
The coupling rods have had Alan Gibson brass coulping rod bushes soldered in place to reduce the rather large holes in the Hornby coupling rods down to somthing appropriate for Alan Gibson crank pins. At the same time the chemical blackening was gently buffed away using a glass fibre brush.
The rods were then put to one side while I worked on the driving wheels. First, a 1.5mm drill was turned very breifly in the hole for the crack pin in the rear of the wheel to give it a countersink and allow the pin to be screwed right home. Don't make the countersink too deep or you'll ruin the wheel.....
I then removed the brass bearing bushes from the orginal Hornby wheels as these get used on the Alan Gibson replacement wheelsets.
Ultrascale laser cut balance weights were added to the Alan Gibson wheels, and the non-driven axles and wheels were assembled, with the Hornby brass bearing bushes and quartered using the GW models wheel press and quatering jig. If you don't have one and want to use wheels other than Romfords, get one, it is quite simply the easiest way to quarter axles and worth every penny.
The driven axle was dropped in place and the overhang on each side carefully equalised before the poistion of the gear wheel was marked using a felt pen. The axle was then removed, put on a cutting mat and with the edge of a file over the gear wheel mark, gently rolled along to knurl the axle to give the gear wheel something to grip. Unfortunatley, the gear wheel proved to be a loose fit so did not bite on the kurled area; it was secured with a small amount of superglue. The driven axle was then assembled. and test fitted along with the other 3 to see what sideplay there was and how many spacing wahsers might be needed. On the driven axle, 1x1mm spacer was fitted on each side. On the leading axle the plastic gubbins supporting the cylinders prevented full sideplay, so 0.75mm of spacers were added on each side to prevent it rubbing on the plastic. On axles 2 and 4 I'm going to try giving them full sideplay in the hope that it will allow 2811 to go round corners without chucking itself into the cess alongside the rails and waving its wheels in the air.
The coupling rods were then test fitted on the wheels and a problem emgered. The Hornby coupling rods are much thinner than the crankpin bush, so there is huge amounts of side play.
I think there are two possible solutions:
1. Dress the bushes down with a file until they are the right length.
2. Replace the rods with either Comet or Alan Gibson ones.
At the moment I'm leaning towards (1) becasue there is always a possbility that the replacment rods may be fractionally different to the honrby wheel base and poor running (if any running) will be the only result.
I shall mull things over at ExpoEM tomorrow and perhaps someone there might have a bright idea....
drduncan
- 3
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