Aug 09

Class 9F – Fitting The Wheels


That heading is a throw-away line for something that is really quite difficult.  The photo shows what you are aiming for – red gears in position and all 5 wheel pairs in place with the crank pin holes in the same position – here shown at the 6 o’clock position in the photo.

The exercise is much, much easier without any of the con-rods attached to the wheels.

First, insert all 5 red gears.  Easy.

You need to decide which hand will hold the loco and which hand will position the next axle.  I hold the loco in my left hand grasping it by the metal that forms the cab on the left of the photo.  I need my thumb or index finger to be free to hold the placed axles in position.

Also, have the 5 axles at hand, along with the baseplate and baseplate screws.

Note that there are 3 different types of wheel.  It makes life easier that there isn’t a left or right side to any of them.  The two rear wheels have rubber tyres (or the grooves to accommodate the rubber tyres).  The centre drive wheel has a square crank pin hole.  The others have round holes.

Place the rear most axle and turn it round so that the hole is in the 6 o’clock position.  Easy.

Now place your thumb over the wheels of the axle to keep it down and in the same position.  Take care not to turn the wheels during the rest of the process.

Now with your right hand, drop the next 2 wheeled axle into place.  Try to get the hole in the 6 o’clock position.  If you manage it first time, then put the loco down, and go an buy a lottery ticket.  Your luck is in.   If you are unlucky like the rest of us, it will have seated incorrectly.  Work out which way you have to rotate the wheel to get it into the correct position, and estimate how many gear teeth this will represent.

You will notice that you cannot simply lift the wheel out.  It has to be rotated around the red idler gear, which is held in place by virtue of the fact that you have your thumb firmly positioned on the rear wheel.  DO NOT allow this rear wheel and gear to turn.  It doesn’t matter about the one further forward.

As you rotate and lift the wheel out, keep its brass gear in contact with the red gear teeth.  When it is free, allow the brass gear to ‘jump’ over one or two teeth in the direction that you need to rotate the wheel, and then allow the wheel to rotate around the red gear as you put the wheel/axle back into position.  Check the position of the crankpin hole.  Repeat this exercise until you get it in the same 6 o’clock position as the rear wheel / axle.

Once you are happy, carefully position your thumb so that it is now holding down the two rearmost axles.

And you keep doing this until all 5 wheel/axles are positioned and are correctly aligned.  At some point you may decide to lift you thumb off the wheels and use your finger instead – particularly if you want to reach the 4th and 5th axles.  Be careful as you lift off – the wheels have been pressed into your thumb for some time, and it will not lift without taking the wheel with it.

If you are happy, fit the baseplate.  I did tell you to have the baseplate at hand didn’t I?

Now pretend you are a little kid again, and push the assembled 10 wheeler around a bit of track.  It should feel smooth and the wheels should move laterally on their axles to take the bends.

Lift the body and axles and check the alignment of the holes on both sides.  Position the axles at 3 or 9 o’clock positions to verify that they all face the same way in a different position on the clock face.