BR Standard Class 4 Loco Build

This afternoon I decided to solder up the parts forming the left hand side motion bracket with reversing lever, originally this was a series of etches which gave this loco brand a bad reputation however under the Scorpio marque this has been replaced with lost wax castings and so the left hand bracket went together with ease, all that was required was the usual filing and cleaning up of mold spatter. So here are the results of today's efforts now soldered to the main frames. The eagle eyed will notice that I have changed the brass axle bushes for better quality ones from Nairn because the original bushes as supplied gave too much slop and I wasn't totally happy in shimming out the lateral travel with washers. A test fitting of the wheel sets proves the slop is much reduced and thus avoiding a short if the wheels accidentally make contact with the brake blocks. I know I can get plastic equivalents but that is not the case as I much prefer using the cast ones instead.

 

And here is the right hand side bracket which came as a one complete casting unit.

And an overhead view showing both brackets aligned correctly, next job now is to prep up the slide bars and fit them to their respective brackets then set up the cylinder block axis and solder into position.

 

Its a Severn Models one Steve, I'll post pics up of the etches when it arrives.

 

Thanks great Toto and thanks but I'm no expert... I leave that to my mentor Mr Pulham. I did wonder if I was boring folk rigid with the obvious and got them thinking oh no its that dreaded BR Standard Class 4 loco build again. So if you are enjoying the read then I'll carry on trawling my way through the motion linkages.

 

Toto as an add on to my previous comments, I've spent this evening and burning a gallon or two of Midnight oil putting the slidebars together. So far both crossheads are fitted and slide freely and the left side drop link is now soldered on and I've coupled up the left side con rod with a 12BA screw and nut. I'll do a few pics tomorrow after I've fitted the slidebar brackets.

 

Today has been a milestone day in the build because the con rods, pistons, crosshead and slidebars with brackets and cylinder block have all been finally fitted. I'm happy to say everything works smoothly after a bit of jiggery pokery and some slight adjustments in a couple of areas where motion movement was a bit on the tight side. The cylinder axis is correctly aligned with the centre of the middle driving axle and the pistons slide freely along the slidebars with the wheel in rotation. Phew I wasn't sure I'd get this far today but I did. Anyway here are the pictures ... enjoy.

 

Yes I feel a sense of accomplishment because so many components come together all at once and being as this is the first outside motion loco in 7mm I've put together I can't really say I'm phased by it. I'm now looking at shortening the front driving wheel side rod bush so that the nut passes behind the con rod, I can then set up the brake rigging then dismantle and spray paint the main frame before adding return cranks, radius rods and other linkage. Trouble with this kit is that the motion is not detachable.

 

I shall air brush this myself, I have an Iwata Eclipse with the Studio Series "Smart Jet" compressor, so I can save even more money . Now I've just spent a wonderful past hour cutting about 1.5mm off the end of each front wheel side rod bush without causing damage to the 12BA thread, the nut runs up and once the excess thread is removed will clear the connecting rod downward sweep... or upward for that matter. I've just reamed out the brake hangers and next I'll clean up the brake tie bar adjusters then solder in place. I'm thinking of adding sanding valves and pipes also, these can be made from 0.7mm wire and thin pieces of scrap etch, I can use micro tube sleeved over the wire to simulate the sanding valves and the steam pipes to work the valves can be very thin fuse wire or something like 0.3mm gauge of which I've got in the spare metals box. Once that's done the frames can be stripped down again and primed in grey.

 

One of the great aspects of scratch building is that the level of detailing is basically determined by the builder's demands and how the model is to look when finished, in my case I much prefer thinking out of the box when it comes to fabricating small pieces and of course there is the added bonus that whatever can be found is mainly cost free. So studying the 4MT drawing recently the main thing jumping out at me is the need for sanding equipment, the pipes, valves and brackets are not supplied in the Jim Harris kit but the sand fillers and boxes are. Now this is a relatively easy bit of scratching to do because I've got a copy of the original drawing Jim Harris used and it shows reasonable detail of the sand pipes, 0.7mm brass wire, some suitable micro tube and a few thin pieces of scrap etch were all the was needed and thus we have sand pipes. So far I've made a right handed left side pipe for the centre driving wheel and a left handed left side pipe to be fitted to the same wheel. I now need to made the opposite handed pair and also a left and a right set for the forward driving wheels, when made I shall solder them all into place and adjust the height and position against the wheel flange. The main obstacles to work round on this model whilst fitting these pieces will be the sprung pick up plunger holes and the compensation beam which has to remain free to move thus keeping the loco balanced on the rails.

 

Now then just a bit more progress from earlier this afternoon, it occurred that it was probably better to finish one side first as if there were any fixing issues with the sand pipe apparatus getting in the way of other things I could deal with it as I went along. So having finished the forward left side front wheel piping I decided to suck the plum and fit onto the mainframe, the first obstacle is the bogie swing clearance made somewhat more difficult because I haven't finished the bogie pivot and springing arrangement, anyway a cursory test fitting of the bogie and it appears there is sufficient clearance. Note also the connecting rods fitted now and there is just enough clearance of the forward side rod nuttage as it travels trough its downward sweep.

 

And here is a view of the sanding gear arrangement from within the chassis mainframe.

 

Here is a better view showing the sand pipe arrangement as per the previous posting's image, I only need to show an approximation of detail and the pipe becomes nicely hidden behind the chassis forward bulkhead.

 

Now the connecting rods are a dry fit at the moment and the leading driving wheel side rod bush has been shortened to allow clearance for the downward sweep of the motion, the con rods are packed out on their host crank pins with 7BA brass washers. As can be seen a lot of clearing of solder has yet to happen on the brake rigging pieces... now here's a story, a replacement brake crank and sleeve adjuster castings are on their way to the Wolds Works here in East Yorkshire since I have utterly no idea where I put the originals for safe keeping. Hopefully the Britannia kit will also arrive and of course pictures when it comes otherwise I fear Toto may shout at me for letting the side down. A well happy days to come what with the Brit and also a Class 24 from Steve.

 

This really is just a pose picture to help me see the wood from the trees and to try and recap on the work completed to date, this is where the build is so far I've dry fixed the front bogie to the mainframe chassis using a sprung pivot boss I made up from a 10BA nut and bolt, a couple of 6BA washers and a spring... all out of the scrap box. When the remaining sand pipes and brake rigging are fitted I will be able to strip the chassis down for painting and then fit the sprung pick up plungers and wire up the motor, I can then continue to refit the remaining motion yet to be made up and then test the chassis on the rolling road. So here we are with another picture.