Friday, October 10, 2008

Garratt Pivot


Garratt Pivot 2
Originally uploaded by Phil_Parker.

Pivots. That's what differentiates Garratts from most other types of steam locomotive*. They need to be meaty bits of kit as, assuming the power units are sharing the work properly, all the force will be transmitted through them. Let's face it, at some point someone is going to hang an unfeasibly long train on the back of this just to see what it can do and 7mm scale wagons are heavy.

The set-up is very simple and quite ingenious. A 7mm wheel bearing is soldered facing up in the boiler carrying part (is there a proper name for this ?) and a suitable sized brass rod fitted.

Garratt Pivot 1Another bearing fitted to the power unit acts as the female half of the arrangement. Initially I fitted this pointing down but looking at the packing that would be required to raise the centre section, took it our and fitted it the same way as the other. I'll still need to pop some washers in between the two but less then before.

* Yes I know - Fairlies, Shays etc. have them too but you know what I mean.

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