Correction of the bogie centre distance and body height

These two operations are linked because the spacer which will allow modifying the pivot position will add some thickness to the bogie frame and will therefore raise the body.

But, on the one hand, as already said, this body is too low, and on the other hand, one can play on the spacer thickness.

Personally, I chose 0.75 mm thick polystyrene, which will raise the body slightly too much (1 or 2 tenths of a millimetre). But as the wheels are of a little too large diameter, if the desire takes me to change them, it will restore the situation. Since the spacer in question will have only a guiding role, it can be chosen thinner, down to 0.25 mm, without inconvenience.

The idea is to remove the current pivot from the bogie (male pin, very offset), to add an (also male) pivot to the (female) body pivot, and to drill a hole into the bogie at the new location of the pivot. It is therefore necessary to intervene both on the body and on the bogie.

Intervention on the body

Here are the parts involved in this operation.

Making the pivots

From left to right: tapping of the pivot placed in a chuck; the Evergreen section and the screw; the same section with the screw tightly screwed; same with the washers installed.

The new pivot is an 8 mm section of ø 3.2 Evergreen tube, which almost perfectly fits into the pivot hole, with little effort. It will therefore be possible, to a limit, not to glue it.

Before installing the pivot, it will be “tapped” by screwing its future screw (sheet metal screw). This operation is done with the tube section tighten into a chuck to avoid deforming it.

Then, ø 3 washers are inserted in sufficient quantity to get a thickness of at least 2.4 mm, so that the bogie has enough clearance in its future pivot.

All you have to do now is to apply very little glue, so not to stick the washers (I used cyano gel) and push the whole into the pivot.

Gluing the pivot

After a few minutes, the screw and the washers can be removed: the pivot is ready. Of course, if you have several coaches, you can batch operate.

Glued pivot

Intervention on bogies

After removing the axles, the former pivot is first levelled. Thoroughly smooth the surface, and make it rough to improve future collage.

Preparing the parts for the bogie

From left to right: the bogie before intervention; the bogie without pivot; the spacer to be added. In the background, a series of parts prepared for six coaches. They are pre-cut using a conical mill bit for engraving PCBs, as can be seen on the enlargement slightly forged…

Making the pivot spacer

Here is the dimensional drawing of this piece. The total length is not critical, but the distance between the two holes is: it will give the new bogie centre distance. The small hole will receive the pseudo rotation stop that will be used to centre the spacer. The big hole is that of the new pivot.

For the sake of beauty, on the drawing, I rounded this spacer like the underlying part of the bogie but I actually left it rectangular…

Spacer drawing

Mounting the spacer

The spacer is glued with cyano gel by centring it as well as possible. The ø 3.5 hole is slightly offset in the length direction from the existing hole, hence the need to drill the bogie in correspondence with the new hole.

Gluing the space

Drilling the bogie

This drilling will not be easy, because the drill bit will tend to deflect and attack the softer Evergreen. I therefore proceed on my Proxxon milling machine, the bogie being placed on a machining assembly: a simple piece of wood whose width is the exact spacing of the bogie sides and whose upper edges are chamfered at 45° by about 2 mm.

Drilling the bogie

In the picture, I have not yet thought of placing a stop to avoid me to reposition the bogie every time. A sharp drill bit must be used to prevent it from deviating, and slowly lowered.

Milling the bogie

It remains to mill the ends of the bogie side beams. Before starting, I wanted to see what was the minimum curve radius allowed by leaving the beams intact. This radius is a little less than 800 mm. At home, it is 500, so milling is mandatory for me.

The milling, in length, must remove the material up to 1 mm from the axis of the axle box. In height, to the top of the “spring” of this box.

Cutting the beam

Milling the bogie

Here I thought about putting a stop! Attention: since the plastic is flexible, the sides of the bogie must be held firmly during milling. We can of course do this with a simple cutter, but it will be less precise, and we always risk an unfortunate slippage…

Attention: don’t go wrong! The opposite side to the pseudo-stop must be shortened, the one that will be directed towards the end of the coach! Here is the bogie in place, seen from below…

Bogie back in place, bottom view

… then seen in profile. Again, the bogie milling is virtually invisible.

Bogie back in place, side view

Note: the green colour of the consoles is wrong. They were painted like bogies, so grey. In any case, the bogies themselves, in translucent material, deserve a painting. I have a doubt as to the orange colour of the seats for the IVa era. Moreover, in the following series manufactured by LS Models alone (ref 40.000 and following), the seats are grey (and consoles too).

I salvaged servomotor fixing screws, with an external diameter of 2 mm; the commercial screws are ø 2.2, which becomes a bit difficult to screw into the Evergreen tube, but nonetheless possible. See Improving old Jouef wagons.

Set of 10 60° engraving milling bits
for printed circuit board
€9.59 (price 2017) at Amazon

This value depends on the thickness chosen for the spacer. It is valid for 0.75 mm. It may be slightly decreased for a thinner spacer.