Having just seen a request for more model pictures to be posted, and as I always like to see others build logs on the forum, here's my attempt.

The loco is a 2 1/2" gauge B&O RR Class P7 " President Washington" that has been partly built to the design of H.J Coventry of the USA in 1928, castings were available in the UK from George Kennion in the very early thirties.I bought the chassis from a fellow 2 1/2" gauge Association member some years ago after seeing it at a rally and pestering him a bit! He had bought it some years before on ebay but had not had time to work on it. The original builder did a good job, but others have had a go over the years and undone his good work., whoever quartered the wheels and made the coupling rods got everything wrong then proceeded to file bits off in order to try and get the wheels to go round, the result being sloppy axleboxes and wheels pointing in all directions.

So far I've remachined the horn slots in the cast gunmetal frames, made new axleboxes, bored on the faceplate in a little fixture to keep them all the same, axles, crankpins. Sorted out the expansion link bracket, as can be seen the trunnion bushes were a little out!. The wheels have been quartered, and at the moment I'm sorting out the cast nickel silver coupling rods, I'll post some oictures of those when they are finished.

The idea is to get the engine completed to be steamable, repairing and conserving as many of the original parts as possible, it is a long term project, I only started it as I can't get on with the boiler for my Crab loco at the moment, but I will update as i hopefully make some progress.

I don't seem to have much control over where the pictures go, so they are all a bit out of sequence, but I'm sure you can work out whst they are!

Dave

Bit more progress on President Washington chassis, Coupling rods, cleaned up, bushed and fitted , i'm afraid I had to use eccentric bushes to get the centres correct, whoever made these got them all over the place, one side was .017" too long and the other side .008" too short. I know i should have bored them to the correct centres, but the nickel silver rods were very thin around the bushes and I didn't want to weaken it any further.

While fitting it all back together I noticed there was little room for the brake hangers, after a bit of puzzling I realised the wheels were over width by about .050", I checked the diameters but not the width, goes to show trust nothing. I had to machine the wheel faces off by holding the finished wheel sets between centres, the cast iron is horrible to machine, maybe the reason they were left oversize as the original builder probably didn't have carbide tools to work with. On checking the bogie and pony truck wheels were also oversize on the width, so out of the intended sequence I had to face these off as well, I like to strip the lathe and clean it out after a cast iron session, so this saved me doing it twice.

Pictures show the rods assembled on the chassis, it all turns nicely now, The bogie is very nicely made, presumably by the original builder, with a nice little leaf spring and everything well fitted and working well, just needs painting while apart. Hopefully pictures below will be self explanatory. Will post more as things progress.

Hi Tom

Thanks, I seem to be making progress although breaking a tap in a finished axlebox slowed things down a bit!

To use the bushes, I measured the centres of the rods as close as I could, using rods in the existing holes (the centre bush is a normal concentric bush) , the difference between the axle centres and the coupling rod centres is the offset required ( say .005" for example).

I turned the outside of the bush as normal to a light push fit in the hole in the connecting rodl, but before drilling and boring it out I removed the bar from the 3 jaw chuck, placed a .005" shim under one of the jaws, centre drilled , drilled , bored and reamed to size. I also made a slight mark on the bush next to the jaw with the shim under it, this is obviously the thin side of the eccentric bush, and parted off. If the rod is too long the mark would go on the inside to shorten the centre distance, and the mark on the outside if too short to lengthen the centres.

After fitting and checking I used some wicking grade loctite ( 290 I think) to hold it in place, although this is really screwlock it is very strong and finds its way through tiny gaps. None of the above is particularly good engineering, but it does work.

I'm ashamed to say my first loco Rob Roy had to have this treatment and as I had no really accurate equipment to measure the error, I made the eccentric bush slightly more eccentric (!) than I thought it needed and turned it untill everything rotated smoothly, then loctited it in, absolute heresy I know but it's still going nearly forty years later!

Hope I've made the above clear, I'm better at bodging than writing, any questions please ask.

Dave

Edited By Dave Wootton on 14/01/2021 18:04:46

Thanks Tom, hope you found it useful.

Bit more progress over last couple of days, bogie has been stripped cleaned and repainted, apart from thinning the wheels to the correct width it required no rectification.This is obviously the work of the original builder, is nicely made and everything works smoothly.

On to the pony truck which was partly made with no provision for suspension, the spring that is visible above the axlebox was just wedged in! pictures show it set up on the mill for machining, this took ages as the casting is quite different to the drawings, so took some figuring out kow best to set it up, the plan was to use the DRO and mill and drill it to co-ordinates, but as the casting is not symmetrical just had to make it as even as possible.

As the rest of the chassis has leaf spring suspension, I'm going to have a go at a pair for the pony truck, I found some spring steel left over from a highly useless set of ebay piston ring compressors that's about the correct thickness, so this should be a interesting learning curve to say the least. It was not intended to start on the bogie/ pony truck yet, but at least it keeps me away from the cylinders which seem to be storing up horrors all of their own. Apologies for the out of sequence pictures, they seem to end up anywhere.

Thanks Ian, progress slowed up a bit as I had a bit of experimenting to do with making leaf springs, I think I said in the last posting it would be a learning curve, and it certainly was. After lots of messing about with blowlamps, sand baths, tiny tin snips and needle files we finally have a set of leaf springs. I had to anneal my reclaimed spring steel and found the best way was to clamp a little stack of embryo leaves between two bits of 6mm steel, soak at dullish red and leave to cool in the hearth, steel could be drilled, filed and formed quite easily. Hardened and then let down to blue in a little sand bed before quenching in oil. Took a few goes to get right but seems ok and springy. Have made a number of different length spares to enable closer setting when the loco is nearer it's final weight.

Marking out and drilling the lower spring hanger pivot holes took ages as the casting is not symmetrical, The main pivot for the truck has had to be drilled off centre, as the axlebox slots are slightly off, it won't be seen on the finished engine, but if i hadn't done it I had visions of the pony truck crabbing down the track like a B-L Mini with a dodgy rear subframe ( remember those?). Pictures show the first trial assembly , apologies for the bits of welding rods as temporary pins, the little spring retainers were a really fiddly bit of sawing and filing. Still got to make the little straps to go around the springs, next puzzle is to work out the height for the rollers that bear the engines weight on the pony truck, something doesn't add up so a bit of investigation needed there.

Bit more work done on the old thing, not many photo's I'm afraid, but someone emailed and asked if I'd given up!, so thought it was time for a quick update, pony truck being painted at present, will post more pictures as soon as it's reassembled.

Been experimenting with leaf springs which is a frustrating business, after trying leather between the leaves as stated on the drawings, which seems ok on the already made main springs, the leather on those must be around 70 years old and still seems sound, this seemed to stiffen up the spring too much for the pony truck. I remembered some .020" thick PTFE sheet used for some gaskets, and tried using that between the springs, gives a nice smooth action so I'm going to see how that works out in practice. Picture shows finished springs, will have to wait until loco is complete to experiment further, made lot's of spare leaves so can set by trial and much error.

Edited By Dave Wootton on 23/01/2021 17:14:51

Doesn't look like a lot to show as far as progress, but the cylinders are now together with the cylinder bores and piston valve bores parallel and the correct distance apart, also machined to fit over the frames properly. It took an unbelievably long time to work out where the cylinders had gone wrong, it looks to me as if the cylinders were the point the original builder gave up and the next one took over, the threads change from whitworth to B.A and the workmanship deteriorates drastically. The faces of the block that join together were machined very out of true in all ways, the only reference I could get was the main bores, so I turned up two close fitting arbours and measured everything from there, I had to use a dial gauge and stand like a comparator to measure the out of square, set up on the mill using machinist jacks and shim to skim over the joint faces, also took the opportunity of getting the bores the correct distance apart, for some reason they were .050" too far apart.

The bottom face of the block was built up with brass silver soldered in them, then machined so the block sits in the frames at the correct height and parallel to the centre line of the chassis. the smokebox flange was also miles out, so this was machined off to the smokebox radius using a boring head as a flycutter, the steam ports were cleaned up, as a result of the heating while silver soldering a small piece of broken drill fell out into the hearth, so that was a result. Oil feed ports were drilled into the steam inlet to the piston valves, the steam inlets are at slightly the wrong angle, but decided to leave as they are, the lagging will cover it up. I'm going to use sight feed displacement lubricators on this, following sucess with one on my Rob Roy, on that the glass is reduced to 16mm dia, going to try a 12mm twin set up on this using what would be one of the air tanks as a oil tank, slowly getting somewhere!

Not much progress on the loco I'm afraid, been accused of giving up again, but been waiting on a large material order which arrived today, in the meantime I've not been idle.Made a mandrel handle for the Myford, small parting tool holders and screwcutting toolholders all to the GHT design from the book.

Today I fancied a change so decided to make the bell and bell frame for the loco, sat in front of a fan heater with a piercing saw and some needle files, surprisingly only broke one blade usually the attrition rate is huge! Nice bit of free hand turning to form the bell. Pleasant way to spend the day. See Terry I'm still working on it!