STEP BY STEP
1
To add strength to the sideframes, I soldered pieces of brass rod into the gaps on either side of the axle units. Bend the brass rod at right angles to allow the parts to be held while making the solder bonds, then cut off the excess and file flush with the outer faces.
2
A reamer or cutting broach tool is ideal for opening out the axle holes just enough to allow the brass bearings to slot snugly into place, without any ‘slop’, as this may lead to the axles being misaligned. Don’t solder them in place yet.
3
The frames were reamed before cutting from the fret to prevent any distortion. When cutting the parts free, use a set of fine brass cutting shears, cutting through from the outer edges of the etch rather than trying to cut the half-etched tags with a knife.
4
With the parts freed, use a file to remove any excess tags to leave the edges square and clean. The holes for the brake rigging will also need opening. Run the file over these – and the axle–holes to remove any raised burrs.
5
It’s always worth checking parts that should be exactly the same, especially chassis sideframes. Hold the two main frames tightly together and make sure that all the holes line up precisely.
6
Next, lay out the side frames and cut out and fold up the spacers. Roughly place in position to ease construction. Leave the two end spacers B and C to one side until the chassis is test-fitted into the locomotive body.
7
With the axle bushes soldered into their holes, pass drills or rods through them while holding the spacers in place on a solid, flat surface. Adjust the frames and check for squareness before tack soldering the spacers in place.
8
With the frames tacked together, gently pick up the chassis and double-check all of the angles for squareness with a setsquare. Once happy, place it back onto the flat surface and solder up the joints properly.
9
Now try the chassis in the body and fit the two spacers with screws into the holes. Check that the frames are correctly aligned and, when happy, tack-solder the spacers in place. Return to the flat surface and solder up solid.
10
Fold up the etched motor mount, making sure it is square. Take care when drilling the holes for fitting the motor. Once happy, trial-fit the worm and gear wheel to make sure the meshing is good.
11
The instructions recommend the fitting of a drive extender to the gearbox, but I wanted to keep the drive train simple. To accommodate my choice of gearbox, the top of the frames require a slot to be cut into them.
12
Solder in the brake supports and then paint the chassis. Red oxide primer was applied first. When dry, the frames were sprayed satin black. When this is dry, use a reamer to clean the paint out of the axle holes.
13
Mount the insulated wheels onto the axles first. These need to be on the same side of the chassis for each axle. I add a touch of PVA glue to the thread then screw in the locking nut. Likewise, I touch the crankpin end into PVA then screw it gently into the wheel.
14
The coupling rods are made up of three parts that must be aligned carefully. After reaming the holes, place the rods onto the crankpins. Use a small piece of paper under the lock nut before soldering in place – it stops the whole job going solid.
15
Glue pieces of copper-clad board to the centre frame spacers. Then solder a piece of folded phosphor bronze strip to the copper-clad board while it touches the back of the insulated wheels (see MR282).
16
A wire is then soldered to the copper-clad boards and connected to one side of the motor. The other polarity is collected by the non-insulated wheels via the chassis, so a second wire must be soldered to the frames and connected to the other side of the motor.