Thursday, 26 July 2012

Coal Tank's Inside Motion

Stephenson's inside motion with single slide-bars.

Most of the inside motion castings are from LGM with some scratch built additions such as the motion plate and connecting rods. The single slide-bars are from Hobby Horse Developments, the crossheads that slide in them are modified Lochgorm Kits' etchings. The joints which articulated when built have been soldered solid now as this is cosmetic inside motion rather than working motion. 

Inside Motion in place with balance weight shaft mounted above

The balance weights will be mounted on the transverse shaft above the motion plate and will be a be a prominent feature between the frames below the boiler and will mask the inside motion to some extent. The motion unit is designed to allow free movement of the front sliding axleboxes. The black wires are the pick up wires taking current from the front axleboxes to the motor.

A busy place between the Coal Tank's  frames

The camera hasn't done justice to the inside motion in this shot, I think that when the balance weights are added the effect will be more striking.

Coal Tank cab and bunker, exterior detail almost complete.

The cab side-sheet beading was made from rectangular stock soldered on and filed to shape. The water filler was scratch built from so many parts that I decided to glue it in place in case it auto-destructed with the next touch of the iron.

Saturday, 7 July 2012

Coal Tank pick-ups

Coal Tank showing pick-up arrangement on front bearings.
The front driving wheels do not lend themselves to wiper pick-ups such as I fitted to the other drivers because the frames are cut away at the front and there's really nowhere to mount them. To circumvent this problem I used a split-axle system. The front axle is a split-axle which is carried in Slaters' 7961 Hornblocks (insulated bearings). The axle runs in square brass bearings which slide in the black plastic insulated hornblocks. You can see the pick-up wires soldered to the bottom of the brass bearings, they then snake through the motion plate to make their way back to the motor while keeping out of the way of the inside motion above. Only the slide-bars and motion plate are in place, forming the basis of the inside motion unit, which at this stage can be removed. The design of the chassis is evolving gradually; somehow, when I eventually get it right, it looks so simple and obvious.