Heljan Class 35 Bolster

This section describes the construction of one of the two bogie bolsters. In practice you would probably build the two bolsters together.

Bolster Frame Remove the Bolster Frame (2) from the fret, and clean up tabs all round.

Frame Folds Make the two folds in the frame, ensuring each is at 90°…

Folded bolster frame …and that the frame rests squarely on its 'feet' on a flat surface, with its top face parallel with the surface.

Cleaning a nut Clean up the faces of one of the 2mm brass nuts to remove any machine oil and grease and prepare for soldering.

Apply some grease to the top few threads of the screw and its head.

Assembling the pivot screw From the outside, pass the screw through the central hole in the top of the bolster frame, thread on the nut and tighten up. Check that the nut is central and flat to the face of the bolster top.

Re-check the folds in the bolster frame for squareness.

Pivot nut soldered in place Apply flux around the nut and run in a fillet of solder immediately around the nut, keeping it away, for now, from the outer parts of the frame where the sides will go.

Bolster Sides Remove two of the Bolster Sides (3) from the fret.

Fit of bolster side to frame Fit one of the sides into the bolster frame…

Inward bias to legs of bolster frame …you may find it helpful first to give the legs of the bolster frame a slight inward bias, as shown, but do ensure that the parts go together square.

Supporting bolster side in place Support the side in place and solder up the joints between the frame and side. Keep the iron away from the area below the secondary spring seating holes (in the picture here, under the clothes peg), just let the solder flow into the lower parts of the joints.

Repeat for the other bolster side. When you solder up the second side, allow the iron to linger at the top of the bolster, and you should find that solder flashes around the folds and joints around the top of the bolster to strengthen the assembly. Apply additional flux and/or solder if necessary.

Soldering to bolster sides Clean up any solder from the flanges of the 'C' channels formed by the bolster, below the secondary spring seating holes: these surfaces will slide against the ears and sides of the subframe to provide the secondary suspension movement.

The one shown here is fine as it is.

Completed bolster Remove the M2 screw from the nut (it should have been prevented from being soldered in place by the grease) and clean up the top face of the bolster.

That concludes the bogie bolster assembly.