A small G3 loco

Discussion in 'G3' started by jamiepage, 9 April 2015.

  1. jamiepage

    jamiepage Western Thunderer

    Cosmetic rear cylinder covers are now complete, and can be held by the slidebars. Some hacking was required to allow enough room for slidebar mounting bolts, and also to easily allow the cover to be removed without removing a crosshead but it has all gone reasonably well.
    Steve Cook, unklian, mswjr and 5 others like this.
  2. jamiepage

    jamiepage Western Thunderer

    Sorry, I seem to have lost the ability to upload more than one photo per posting. Herewith, for the record, a view showing the hacking needed on a rear cover. IMG_0001.JPG
    Steve Cook, unklian, mswjr and 6 others like this.
  3. jamiepage

    jamiepage Western Thunderer

    Over two years later, I've decided where to go with the valve gear and actually made some slight progress.

    I'll stick with the Stephenson's gear, but have redrawn the set up with lifting links positioned outboard of each expansion link.

    The original problem with inboard lifting links was a foul with the boiler underside. As now positioned, the boiler can sit at scale pitch without fuss.

    A weighshaft/ lifting arm assembly was silver soldered up. The main shaft is a hollow tube, cut to fit between the frames, and the assembly rotates around a solid rod. This rod slides in from one side and sits in holes within each frame; it will be trapped (probably) by slide bar brackets when they are bolted onto the frames in due course.

    Here's a snap of the LH components in situ and in full forward gear, with temporary pins to hold all together.


    The frame cross member is milled from brass and supports each valve rod through a bush. (Well, just a hole really).

    The expansion links were machined, with silver soldered brackets for lifting links. A straightforward turned bobbin acts as a die block.


    As can be seen, although prototypically Stephenson's, no attempt has been made to scale the components. In fact, they are quite crude but will hopefully do the job well enough.
    This is the RH gear, looking outside in.

    The overall idea of producing a 'garden railway' type loco for some standard gauge G3 live steam, R/C shunting remains.
    A Roundhouse type gas fired boiler with standard Roundhouse regulator/ gas/ etc components and a Slomo between the frames completes the spec.
    The boiler could have been a standard Roundhouse item, but there is some extra length available so a slightly longer boiler is being produced professionally to take advantage of increased capacity. All other items will be bought off the shelf.
  4. michael mott

    michael mott Western Thunderer

    Hi Jim
    The link you posted to is my work. The loco is one of the crew 18 inch tramway locos that was used at Crewe, the loco was named Dickie and had a unique valve gear and I could not imagine how to machine up the spiral with my Myford so I cut off the alternate teeth from a piece of pinion from something that was salvaged and then heated up a short section to cherry red while it was clamped between the 3 jaw chuck and the chuck in the tailstock the rotated the main chuck 180 degrees let it all cool down and it works. The loco is 2 1/2 inch gauge.

    adrian likes this.