Ever since we started building the JLTRT kits for the TTA wagons we have had continuing battles with parts made from whitemetal - the brake lever guard is a case in point. This part is "exposed" and fragile, failure rate is roughly 75% by the time that the model is ready for painting - seems to me that a brass casting is a more secure option. Talking with Chris Brown (
@ChrisBr) we worked out a route that could produce the required castings albeit that route depended upon third parties.
Starting with what we had, an unused whitemetal casting, Chris prepared a CAD drawing. Comparison of the original part with a photo courtesy of Brian Daniels's (
@Brian Daniels) showed that some changes to the drawing might be in order for the length of the guard and the arrangement of the stay between the lever guard and the axleguard. Further, Brian's photograph showed that the brake lever guard could benefit from being moved to the right to provide clearance between the stay and the axlebox (look at the placement of the guard relative to the rivet pattern on the solebar). This is the photo that was used for comparison purposes.
Copyright Brian Daniels
Chris arranged for a trial print through Shapeways and I modified a part built underframe to (a) move the brake lever guard to the right and (b) introduce a hole in the axleguard for a spigot that had been included on the back face of the stay. Photos below show the JLTRT casting and our replacement 3D print.
An underframe with a JLTRT casting
An underframe with our 3D print
[the hole in the axleguard is from a previous use of the underframe and represents the fitting point for the original JLTRT casting, this hole shall be filled with solder at the same time that the brass guard is fitted]
Next step is to arrange for the production of castings. David White of Slater's Plastikard has the .STL file for use in producing a wax master, he assures me that the master is going to be used to produce a mould and that eventually I shall receive 20 castings (for Peter's kits and for Ian Roll).
I have been given an estimate of price, a firm price is awaited. Anyone else interested in this part? (Richard? (
@richard carr))