May saw the usual gang working on other things (OK I skived of to drive some trains) resulting a couple of weekends when only part of the team was working on the engine culminating a full team effort over the Bank Holiday Weekend at the end of May.
We even press ganged a few passing volunteers. Thanks for your help Roland and sorry you had to put up with Jo's cleese style German and we were pleased to give David Othen a day off from being works scapegoat.
Pony Truck Repairs
Whilst on holiday in Caernarfon Blanche had a little "off
road" adventure
with the pony truck being derailed. It wasn't very serious but even a little
bump can cause hidden damage that can't be seen from any of the normal views you
get of a locomotive.
However, when you can lift the whole thing above your head and have a good look at the underneath then you get an entirely different perspective on things. Also whilst you have the ability to lift the loco easily that is the time to get the pony truck out. To give an idea of how quick this can be achieved it goes like this: -
Lift the loco - remove leading driving wheel brake gear - swear when the pull rod drops on you (it always does!) - undo the truck lubrication pipes - remove the truck pivot pin - lower the loco to the ground - remove the truck lifting stay - raise the loco slowly pushing the truck forward so it drops out as the loco rises.
All done in about 30 minutes as opposed to half a day jacking and packing the old way. back to top
With the truck out it was cleaned and inspected and no damage found to the main body the other bits were in need of attention. The Mouse catcher, a bar for sweeping stones etc of the track has burst along the corner of the angle iron and will either be welded up or replaced.
The sanding stretcher also looks worse for wear and having had a Dinas based repair. Its not very clear in this photograph but the stretcher is the horizontal bar with a vertical tube at each end. You can just see that the right hand tube is both longer and the other way. The pipe is already shorter and the angle will be adjusted when its refitted
The truck is now back under the engine. Refitting it is the reverse of getting it out although it involves appreciably more swearing, two pieces of string and a temporary pivot pin. The string guides the flexible oil pipes from the truck axle boxes up to the oil pots, the temporary pin is smaller than the real thing but does unit we get the loco over a pit and can fit the proper one which is a tighter fit. The swearing? Well it never goes according to plan - the string snapped! back to top
More Gizmo earlier episodes in the saga
The previous instalment in the Gizmo saga saw the Gizmo invented and partially assembled and tested. In this thrilling instalment it was found not to work and in need of a modification.
First
job this WP was to modify the guide ring so that it actually fitted in to the
flue hole
in
the firebox
The idea is that the outer diameter of the guide ring locates the clamping ring as shown in this picture from the Easter WP. The thing to note here is that the two rings are sat on flat surface and would be fine in a boiler where the tube plate is flat. Unfortunately Blanche's tube plate is not flat. As we are only replacing the superheater flues all the small tubes are projecting through in to the firebox and have a sealing weld around them.
This
gives us two problems, firstly the ends of the tubes don't give a flat surface
to clamp against and secondly the clamping ring is spaced too far away from the
tubeplate to engage the centreing ring. To sort this out the clamping ring has
had a rebate machined on the back of it. This was done by setting it up in the
lathe to run true, as shown here, and then machined to leave just a thin ring at
the original thickness to bear on the tubeplate whilst the rest is relieved to
clear the tube ends
This view shows the machining in progress 
And finally the clamping ring sitting around the centreing ring inside the firebox
To
hold it all in pl
ace the clamping ring is going to need to be clamped very
securely and this is being achieved by placing some long lengths of pipe into
which lengths of studding have been screwed in small tubes adjacent to the large
holes. At the smokebox end small caps have been made to fit over the tube ends
to ensure that the clamping load is taken by the tubeplate and not the tube
ends. An option that may be pursued is to tack weld a strip between these rod
ends so they don't rotate when being tightened from the firebox end. At the firebox end the
studs simply protrude at the moment. When the gizmo is set up to do the cutting
clamps and brackets from the milling machine will do the business.
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Valves and Valve Setting
Another job
done over the weekend was a valve overhaul. The
Pistons were done on an
earlier weekend when the camera was absent. Firstly the glands and front valve
chest
Inside a valve chest. Very little wear was evident although there is evidence of less than ideal lubrication which will be investigated.
There
was also evidence of valve fitting by hammer and chisel which had to
be removed before the correct valve insertion tool could be fitted in place.
A freshly removed valve head with the rings removed. Close up of a valve head during cleaning
The valve heads were cleaned with the rings removed. The rings were cleaned and
checked for wear of which there was little suggesting the possible lubrication
problem is not serious.
As part of the valve overhaul Jo had to file and emery quite a few marks off the valve spindles which looked very much like the work of a pair of stilsons. It is important to clean this off and get the spindle smooth as it runs through bearings and gland packing.
The perpetrator had better remain anonymous as RicketRescue have issued a Fatwah for the culprit
Having removed the valves for overhaul it is important that they go back in exactly the right place. Valve setting is important, it affects the economy, power and wear and tear on a locomotive.
Boston Lodge is fortunate to have a little used "rolling road" know as the valve jigger. This is inserted in to the track on 2 road in the old erecting shop and the driving axle of the locomotive lifted on to the rollers. The connecting rods are removed so that only the one axle is rotated. This axle can then be rotated in either direction at will by a simple air motor.
Marks on the face of the wheel, marks for when the cross head
is at back or front dead centre and measurements of the valve position relative
the the end of the valve chest allow the valve position to be adjusted to give
even exhaust beats. This view shows the fireman's side valves being set. The
driving wheels can be seen sitting on rollers, the green shift is the drive from
the air motor to the rollers. Jo is wielding a set of callipers having been,
measuring the position of the marks on the wheel face.
I had intended to take more photo's of the valve overhaul but it all happened very quickly whilst I was machining the gizmo.
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