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4472 Flying Scotsman 5"


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Hi guys


Although I have been a member of this forum for 7 years it's only recently come to my attention that there is a Model Engineering section, IIRC my first post here was seeking info on 4472 and the place that I log into the most is 7mm as one day when time permits I plan to build a layout in the senior gauge. Now that I have been made aware of this section on RMWEB and if people are interested I'm more than happy to post updates of my build here. I little background on me and the locomotive, I'm semi-retired with a long history working in films/TV as a senior visual effects technician, this role covers many titles, model maker, engineer and special effects among many others, my last role was as 'Art Director' on a British independent film.

So during my time both in films and in a previous life in ICI I have done/made many things, I have no formal training in engineering but have learnt an awful  lot over the last few decades from those who have during my role in the film industry.. this is my first live steam locomotive although during the last 7 years i did pick up a half built Heilan Lassie just to get a clearer understanding of the operation of a steam locomotive, this model was finished and first run some 3 years ago. I don't get chance to run it these days as i need to get 4472 finished and if I have enough time left build some Gresley teaks to be pulled behind her, I estimate approx. another 10 years before completion of Flying Scotsman as there's an awful lot to do, i would expect the scale backhead fittings and injectors to take a year or more alone.


Enough about me, on to the project...... as i said, my first visit to this site was 7 years ago searching for research info on 4472,  the project has come on a long way since those early days, prior to this I had been building up my research info into this locomotive, this began approx. 19 years ago when i bought the drawings to Don Young's Doncaster, IMHO the most detailed and closest representation of the class by a man who worked on them and was a professional draftsman, I also refer to works drawings.  I would like to think that as of today there's very little that i don't know about this loco, it's various incarnations, it's history and most importantly what i need to do to reproduce an authentic model (baring modellers license and physics) of the most detailed model possible of 4472 as she was in A1 guise in the late 30's The learning never really stops though and I'm always picking up new pieces of important info as I delve deeper into a particular part, this for me though is a big fun part of the exercise. a big reason for posting here is to help increase viewing as many of those on these pages share both engineering and model railways, I certainly do.  I can't copy/paste the last 7 years as it's just not feasible, the time this would take would be immense, however if people are interested I'm very happy to include this forum in all of my future updates.


A few photo's to show the model so far, I'm not sure if there's a limit or not for posting images on this forum, some of my updates have 10 or more images so please let me know if this will cause a problem?


hope the images come out.. :)


Kind regards




edit: now that I have found a way of correcting the image issue I have  added a few more to this first post
















Edited by greenglade
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well I have edited the original post pictures.. the only way that I could get them the correct way up was to try taking pictures from the desktop using my phone at different orientations... got there in the end but afraid the quality is pretty bad. If an Admin knows how to rotate pictures perhaps he'd (she) would be so kind as to let me know how?





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I've had this problem too with iPhone pictures. I get round it by emailing them to myself, then use Photos on a Mac to crop/rotate before posting.  My wife does the same with Microsoft Picture Manager on her Windows Laptop. 


The build looks great BTW.

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Evening guys.. well I've just posted an update on the mech forum and my FB page so will copy/paste the details here... it's only small for tonight and of course you won't pick up on any reference i make to previous updates, some of these guys have been following me for 7 years so it may take those interested a little to catch up. I am currently working on the middle cylinder, I have finished the main bore except for final honing and am now working on the 7 degree angled jig required for the next stage. for thos not familiar with Gresley's design, the middle cylinder is inclined at 7 degrees to clear the leading axle but the steamchest is horizontal so that all steamchests are on the same elevation or the 2:1 conjugated valve gear wouldn't work...anyway, that's where I am up to, this is tonight's small update...


Now that the PC is running properly again I can continue with the updates, first picture to finish off where I left off, that being the machining of the slide bar bracket to a height of 3/4" from the centre of the bore below. Now one thing that is becoming more obvious as i work through this casting is that it was clearly a bad one but I'm managing to get around it. The cast itself has been cast offset, that explains the odd shape of the steamchest ends and now that i get to it the offest of the slidebar bracket. I of course centered on the bore below and machined out the bracket to it's 5/8" width, here you can see that there is more meat on one side than the other. Not so obvious in the picture but when using a square the bracket is slightly to one side of the bore? I have no idea what happened during the casting of this pattern, clearly something moved but as long as the steamchest bore machines without issue I think it will be ok, I wouldn't want to have to do all this again on a new casting. When looking at the outside cylinder castings there are none of these issues, they are like a Rolls Royce' to a mini...lol Perhaps i should have rejected the casting when received but to be honest having not seen one before and having not machined it I was a little blind to the problems, still onward and upwards..



Today I have made a start on the jig for holding the middle cylinder at 7 degree's, before machining the angle I first needed to transfer the mounting holes for it to fit on the cross slide as indeed I did the first jig block for machining the main bore. Picture shows the block having had it's face machined flat, (this block was an offcut from my son's work, it had been CNC'd on the lathe and thus had the marks associated with this, easy enough to remove) and the holes partly drilled using the other block as the template, once the angle is doen I'll finish the holes to size, I just needed a register for now.




and so after a few hours of machining I had the block to the angle required..



I thought it prudent to finish today's effort to check what angle that the casting was showing before machining... no surprise then that it's out and by some margin at 1.2 degrees, if you recall there was no machining done to the bottom face, it was just flattened with W&D on a flat plate after removing a couple of high spot blobs of metal with a file so I know that the bottom hasn't been machined out of true. As you can see the digital gauge is showing a reading of 5.8 degrees.




Just to be sure that all the parts are talking to each other I placed the casting on the machined jig to check it's reading too.. yep.. 1.2 degrees out..


So my next job will be once the holes are finished to set the casting up on the bed using the angled block and machine the top to be horizontal, I could possibly leave it but that would leave me with no datum to check the cylinder against the frames to be sitting fully horizontal in it's proper position, any error here would put the 7 degree incline out. While in this setup I'll also take care of the exhaust and blast passages which will need tapping too, I'll cover these details in the next update... thanks for looking in guys...


Edit:  Well clearly I have a problem with uploading pictures, these were all taken with the camera (phone) the correct way up so I'm at a loss, I hope that this can be resolved with the help of an admin, I wouldn't want to be responsible for giving you guys a headache trying to view my pictures... :)


edit2: Ok i found a way of sorting this post out but don't think it's practical long term as I have had to copy links from Imgur hosting site and use those, only problem is it duplicates the images on my PC which isn't a good idea.. I'm told that this is a 'forum' issues rather than my side, perhaps an Admin can help?     cheers

Edited by greenglade
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Welcome to RMweb formally. I post as kipford on Model Engineering Clearing House and have been following your 4472 build with interest as I will be starting properly my first 5" gauge loco (Don Young Aspinal Class 27) when I retire (early) this Friday lunchtime. I have been modelling EM gauge for the last 25 years in two periods LNWR pre-grouping, with the SHMRC and modern image with my own layout.

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Hi Dave...thanks for the welcome...


Being a great admirer of anything by Don I hope you share your build for all to see.I have a soft spot for pre-grouping loco's, they have an elegance about them which my eye enjoys, the Aspinal Class 27 is a good example of such a locomotive. Retiring Friday?...well done to you sir, I hope you can get stuck into the build asap...:)





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Good day all, this will be my last update before Xmas and perhaps the New Year although if allowed I will try to find time for a little more model engineering, it's good for the soul...honest.

First up was to machine the top of the flanges so that they are exactly 7 degrees to the main bore, this will make life much easier for checking that the cylinder is at the correct angle when fitted, there's a fair bit of work involved before I can do this and will touch on it at the end of this update.
Here we see my set-up for holding the cylinder, as with the mounting block for the main bore I have added a side support to ensure that the cylinder sits squarely on the 'x' axis for both mill and lathe and also I have added another support plate to the rear (right hand side of picture) to be able to lock the cylinder to the incline without any fear of it slipping. The angle gauge is used just to check that nothing has changed once bolted down. I forgot to add before that the angled block had slots machined in it for holding on the mill bed (the drilled holes for the bolts will be used for the lathe), the cylinder itself is held on the slide bracket at the rear and the front of the steamchest at the front, not the greatest of methods but it worked with no issue.



After machining the flanges down to the correct angle (machined the webs too to match) I moved on to the steamchest steam inlet hole, after plotting the center and cross referencing with the dimensions on the drawing I center drilled the top of the inlet stub. Note the exhaust spigot has also been faced off.



It was then on to tapping the 1/2"x32tpi thread into the steam inlet...



So that's the inlet taken care off...




Next up was the exhaust spigot, first job to machine the spigot to 7/8", I did this using the boring head which of course involved the tool bit being held inverted and the mill switched to run in reverse.


then it was the turn of the bore itself opening it up as far as possible for hopefully better steaming, not forgetting that for this the tool needed to be turned around and the mill switched to forward.


Now when cutting the thread on the saddle exhaust spigot It was easy to do as the saddle was held in the 4 jaw for machining so easier to get the die square to the spigot, for the cylinder I've gone a little 'heath robinson' and done it by feel and eye with the help of a bubble to ensure I didn't run out of square during turning.



That's the inlet and exhaust passages taken care off... now with reference to my comments at the beginning, I'm going to spend some time getting the cylinder to sit in it's correct position before machining the steamchest, the reason being is that there's a lot of jiggling around to do here to get things right. There are a number of points to consider first, the bore must be at 7 degrees to the frames, the steamchest must line up with the 2:1 gear stay, there must be clearance for the saddle which when fitted becomes one unit with the cylinder. In the picture the cylinder is roughly in place, it needs to sit lower as in it's current position it's to high blocking the position where the saddle sits above it, the holes shown in the picture are the top 4 for the saddle and the lower 6 for the cylinder. Before I can lower the cylinder I need to remove a little from the rear flange corner to clear the vacuum stay howvere before doing this I need to ensure that the cyliner is in it's correct position distance wise from the saddle exhaust spigot which the drawing states (ref 2 1/2")...now for those who have been following the build for some years you may recall that I have moved the smokebox back 1/8" to match photo's of the prototype, this I believe all has something to do with the front bogie changing from swing link to side control but i won't go through all that again now.



This is where we are at for close of play 2017, things are looking good if a little perplexing getting my head around all of the parts that need to add up for this to work, next update should have the final position of the middle cylinder sorted, the saddle drilled for the cylinder exhaust spigot, the steam inlet and also the bottom of the saddle to give clearance for the exhaust passage ways, lot's to do there...



that's it for this year, I'd like to take this opportunity to wish everyone a very merry Xmas and assuming I find no time during the festive season for a further update a happy New Year.

Merry Xmas



edit: seems the pictures have gone wrong again.. I'll try to sort this out later...cheers


edit2: well I've managed to sort the images but seem to have two stuck at the end?...can't seem to move them but at least the pictures are up the right way now... :)



Edited by greenglade
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Hi David


Thanks' for your kind comment.... no the castings are not from my patterns although I have done a fair bit of pattern making in my past career.. The designs are all to Don Young, alas I have forgotten the name of his pattern maker who Don did name but he has done a great job in being able to cast in most of the exhaust/steam passages. However the foundry work for the middle cylinder that I'm working on now leaves much to be desired. If I had paid more attention to it when purchasing some years ago I would have rejected it, the outside cylinders in comparison are light years ahead in quality, but 'hey hoe' these things are sent to try us, I think that I should be able to get a working cylinder out of it, I'll know once the steamchest has been machined.... fingers crossed..:)





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Sorry to hear the middle cylinder is sub-par, a lump of bronze like that must have been expensive. Looking at the work so far it seems you’ll be able to sort it out!


Most iron castings we get down here are pretty awful. There are very few foundaries left and they don’t take a great deal of care for our little segment of their business. Bring on the time we can get printed sintered metal parts cheaper than castings.


I’m looking forward to following your build in the new year.


Regards, David.

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  • 4 weeks later...

That's a really nice build.


Currently completing a rebuild of a 5" Brittania. I had it running last year and it showed up a lot of changes that are needed.


I am working on the tender at the moment to get it in shape, adding detail and correcting faults of the original assembly.



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Hi guys


thanks for the kind words and my apologies for having no updates of late, I've been waiting for the weather to warm up a little before spending hours in a damp workshop, not been in top form since xmas so spending some time in the warm...having fun thought building a plastic kit...must be nearly a decade since the last time I worked with plastic...it's rather relaxing after machining cylinders...:)  I'm guessing that you are working on full size Giles, or at least 7 1/4", I'd love to volunteer for a preserved railway...none near me but we do plan to move and one of the items on our 'new house' list is a preserved railway near by. Good luck with the Brit Brian, nice loco's...Yes Ian they are a tad expensive, the 3 cylinders costing approx £1k, not something you want to mess up...:)


Promise to do an update soon guys...





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Your welcome, its hard when the house is warm and the garage or workshop cold. But modelling takes many forms, i can switch from model yachts to plastic kits or anything. My wife thinks i am barmy but its all fun and satisfying pastimes.



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  • 2 months later...

Good day all..It's been a while since my last update, I've been doing a little more work over recent weeks and now seem to have found my way again....anyway here's were I am now, I have stripped down the frames and busy working out where the middle cylinder sits....here's the latest update....

I have a fair number of photo's to show today although in physical terms not a lot of progress has been made but it's an important step that i'm working on and so will try to show how I'm dealing with it. I am of course referring to the positioning of the middle cylinder, I'm not there in machining terms yet but have hopefully covered most of the ground work ready for fitting. There is very little info given in Don's words, in fact unless I've missed it all he says is to drill the holes, either for bolts with nuts on the back to secure or to be tapped 6BA, I'm going for the tapped option,purely as I don't fancy in any future maintenance having to fiddle around with nuts in hidden places. There is very little on the drawings either but the one measurement that is given is to be honest all that's required, it took me a few looks to find it so would have been nice if Don had mentioned it in his words, after all, the positioning of the middle cylinder is fairly critical to a smooth running 2:1 gear.
I have included a picture of the drawing as a visual aid to describe what I'm on about. The top left drawing you will note the measurement from the center flange to the most forward of the mounting holes, that being 1 37/64, probably not that best of things to measure from, that being a rough casting but that's what the man says and who am I to argue, I guess the position isn't as critical as i had assumed?


The next thing to check is the height of the cylinder, the known hole gives me both axis required as the top edge of the cylinder flange runs parallel with the frames so it's just a matter of pivoting the front upper right-hand corner (looking from the right hand side) to get it's position, basically that one hole and the angle of the top edge is my datum. This picture shows the underside, it's all pretty tight here, the bar that I've pushed through is the main cross shaft for the drain-cock apparatus, there are in fact two crosshafts, but these details are for another day. Note that the hole for the shaft is just below the line of the bottom row of mounting holes for the middle cylinder, as i said, very tight, clearly a section of the cylinder middle flange will need removing when it comes to fitting the pulley for the bowden cable to operate, I'll need to remember that before final fitting of the cylinder. 


The final thing to check here was the position of the steam chest in relation to the 2:1 gear stay and the outside cylinder steam chests as they all need to be at the same height and parallel, this check is the last to show that the cylinder is at it's correct height and things begin to become clearer in ones mind, or should I say i breathed a little easier. Anyway, the picture shows the cylinder in position with a length of BMS bar pushed through the as of yet un-machined steam chest as a visual check on how things are looking, I also checked with one of the outside cylinder flanges in place and a cylinder casting held by hand to see if anything looked amiss, all looks good, needless to say i couldn't take a picture with all of this for obvious reasons..smiley.png


One thing that has become very obvious is that I still have a fair bit of material to machine off the top edge of the cylinder flange I tend to leave such things oversize anyway to play safe, especially when there are no overall sizes given for the flanges in the drawings, i hadn't realised though that it would be as much as it actually is, more of that later. first job though is a little more machining of the saddle. I hadn't finished machining the bottom flange edge yet nor had I drilled the holes for the steam inlet/exhaust pipes, I had left all of these until I was sure of the middle cylinder's position. with the cylinder's final position known I could line up the saddle on the frames and plot exactly where I needed to drill the two holes. Before starting these I machined the lower edge of the side flanges and back edge too , IIRC this is about 5/16 from the lip that sits on top of the frames, with this done I could now work out how much needed to come off of the cylinder flanges, hope you guys are keeping up, I'm getting lost just writing it...smiley.png Picture was taken as I made a start on the exhaust passage from cylinder to blast nozzle. Now the drawing states that this hole is 2 1/2 inches (REF) back from the exhaust hole from the outside cylinders, those who have been following me from the beginning may recall that I have positioned the saddle 1/8" back from that shown on the drawing, this is to keep it closer to the prototype ref photo's that i have and IIRC to match Don's GA. I did go into this in more detail some time ago but basically I think the error, if you can call it that, comes in due to the re-positioning of the front bogie from when it changed from swing-link to side-control types, the bogie yoke is actually moved 1/8" due to this change and perhaps why it looked wrong?


Here I have machined down the flange to 5/16 from the lip as mentioned and also finished the two steam holes, the exhaust in the centre and the steam inlet to one side, the drawing states to drill the inlet to 13/16, I haven't done that, I'll wait until I know the exact size of the pipework that connects here, the smaller the hole the easier to seal for a vacuum is my way of thinking. I will most probably make up some stainless baffle plates to go around the pipes ho help with this, Don just states to fill with asbestos or today's safe variant but I like the idea of fitting baffles, final decision on this will be when I know how much room I have to play around with inside the smokebox to be able to get to the fixing screws for the planned baffles, that's another on of those jobs on the back burner... Note that I have also cleaned up the inner edge of the flanges and reduced both the bottom area around the exhaust hole and taken out a section of the rear flange for the exhaust passageway to fit. Not very pretty but it's all going to be buried and out of sight so not a concern, well not to me, I have plenty of bits to do that will be seen..smiley.png


With a little trial and error I got the saddle machined enough for the cylinder to sit on, now I have more to do here but will leave it until I have finished machining the cylinder flange down to size in a hope of keeping the fit between them as good as possible. The pen marks are from earlier when I was trying to get some idea of how much metal needed removing , it's not as much as it looks here and yes I know that the line isn't running parallel to the blue dots, it was just a rough guide, clearly the cylinder had moved during marking.


Here you can see how much does need to be removed form the cylinder side flanges, I'll need to re-jig the casting for this, that's a job for Thursday..


A view from above, the rectangle shape in the casting around the rear exhaust hole is roughly what needs to be removed for the saddle to sit down lower onto the cylinder..


Another to show that the steam inlet lines up...


Final picture for tonight is just me double checking that things are as should be, with the middle cylinder in place and parallel to the top of the frames i wanted to see if the main bore was still sitting at the required 7 degree incline. For this I pushed a length of 1/2" BMS into the piston gland opening, calibrated the gauge to be zero on the top of the frames and placed it onto the BMS bar.. ok you can wiggle it + or - 0.1 degree due to the play in the gland and length of bar but it's where it needs to be which is nice too know... 


So, I know what I'm going to be doing this week after completing my grandfather duties, first will be to machine down the top edge of the cylinder side flanges, that drill/tap all of the 6BA holes, the forward of which are shared with the outside cylinder flanges, I tell you things are certainly close fitting on this design....smiley.png With all of that done I will re-check the frames for required holes (still need to do the bowden cable clip holes, will make a jig for those) and then I may be able to take a look at a good clean up and getting some paint on the frames, now that I am looking forward too....smiley.png

thanks for looking in guys..


Read more: http://modeleng.proboards.com/thread/5733/building-don-youngs-doncaster?page=121#ixzz5EBjhBcPJ

Edited by greenglade
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Hi guys...

Will I hadn't planned to do anymore on 4472 until Thursday but after finishing my babysitting routine this morning I found myself chomping at the bit to machine the cylinder and saddle until they fitted together, it just had to be done...smiley.png I machined the top edges of the cylinder side flanges down by 0.220 which was the measured gap between saddle and frame from yesterdays work. With that done i marked out what needed to be removed from the saddle for the two units to meet. I did this in stages trying to keep the hole in the saddle floor as small as possible, the rear wall was just a matter of cutting away until it cleared the exhaust passage to the steam chest. I have two pictures to show, I didn't bother taking a picture of the cylinder set up on it's 7 degree incline jig for machining as it's the same process as shown before. Later I'll also tidy up the ends of the flanges, especially the part that was badly cast, having now sorted out most of what's what, I think that I should be able to loose most of the rough part.

First picture taken from the side, I should have taken this looking more from the rear to show the area cut away from the rear wall of the saddle, you can just about get some idea of it from this picture though. Two things that I will need to do, the two blast pipes need to be of the same height, there's plenty of thread on the front pipe so I'll remove some later. Also I need to open up the rear pipe so that the bore is the same size as the front, again, I'll take care of this later. I haven't drilled the cylinder mounting holes yet, I'll leave that until Thursday when I have the whole day to take my time, most important is to remember not to drill right through on the steamchest side which is why I'll start this afresh on Thursday morning. 
To get the cylinder lined up with the saddle properly I rested the cylinder on the drain cock cross shaft, lined up the forward vertical line of holes (those that share with the outside cylinder flange) with the scribed line marked as described in the previous update and then ensured that the top edge of the cylinder flanges were parallel to the top edge of the frames, so basically 3 reference points were used. I also eyeballed the steamchest to 2:1 gear stay to ensure it's somewhere in the middle height wise. When I drill the holes I'll check that all is set as described and clamp to the frames for transferring of the holes. Hope that all makes sense, once this is done I'll remove a small amount from the bottom of the cylinder so that it's not resting anymore on the drain cock cross shaft, I may also take a look at where the pulley sits on this shaft and remove the required amount from the cylinder's central web.


Not much to add for the second photo other than to say it's taken from the front and that I will remove some metal from around the rear pipe so that I can later fit a baffle plate flat to the floor of the saddle


Anyway that's it for this unscheduled update, I just wanted to share as I'm quite pleased that things seem to be falling in place, this is a little involved and a bit of a head bender, the outside cylinders are pretty straight forward, having no incline and seeing as the flanges are already done, I just need to machine them and then fit accurately to their flanges, should be a piece of cake after this lot....smiley.png

Friday I should be happy and giving the last update for the week...fingers crossed....see you then...smiley.png



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evening all..

I've brought this update forward as it seems I have decking to sort out over the weekend...smiley.png all's ok though as i got done what I wanted for the end of this week. I have a few photo's for tonight's update cylinder is now where it belongs and i've done a number of other jobs that weren't shown on the drawings.
First up the drilling/tapping of the 34 holes for 6BA bolts, I had been a little puzzled getting to this point as there's 38 holes in the frames, things soon became clearer though once the cylinder was in it's correct position and I began drilling the holes. I'll cover the side where all holes are used first, this picture is the right hand side (drivers side), most screws as you can see are CSK, the front verticle row are hex heads as these are the ones that share the same holes as the outside cylinder flange which has all hex head bolts holding it to the frames.


For the fireman's side I needed to be more careful as there are a number of blind holes, Don makes no mentione of this, or in fact that 4 of the holes are redundant due to the proximity of the steam chest, or should I say I can't remember him saying anything about it. To ensure that I didn't drill too far and break through into the steam cheat or an exhaust passage I used a stop on the drill, the stop seen in the picture I ditched as it promptly dropped off when dipping the drill tip into cutting fluid, I didn't bother taking a picture of my final solution which was simply a Dremel sanding drum rubber that was taped to the chuck to stop it falling off, an added bonus was it didn't score the frames either and could be pushed up hard against the frame for each hole. 


Here's the other side, the bottom row plus 1 up on the rear are drilled straight through, you can see the 4 unused holes which are where the steam chest runs very close up against the inside of the frames, IIRC along the top row there are 3 straight through, the others are up against either exhaust passages or the steam inlet area. I will admit to giving a sigh of relieve getting to this stage, I don't think that there's anything else in the build which is as taxing to one's mind as fitting this middle cylinder, well not for me at least..smiley.png


I've included this picture just to show that the part of the casting that I thought was damaged will be fine, now that I know where the bolts are I can machine the edge down to suit and tidy this part up.


Now for the parts that aren't on the drawings, or as I say I've found no reference to then in either the words or music as curly would say. First is the expansion bracket on the drivers side, having taken closer looks at what runs along the frames trying to get them ready for paint I noticed the linkage arms for the lubricators, at first i wasn't sure of I was misreading the drawing which to be honest is very vague in this area. Don has included a drawing of the drive arm and the link's that connect up to both of the lubricators but it's not shown in relation to the other parts around it? When looking close it's clear that the link to the rear lubricator is impeeded but the expansion bracket, luckily I did take some very close pictures of this area which confirmed ny suspicion that there should be a vertical slot in the bracket for the link to pass through, well that's how I see it at least. picture shows the expansion bracket bolted to a right angle for me to drill and then machine the slot, it's actually a 'triangle' section so extra care is needed. I have positioned the slot to be offset from the slot in the running boards which the lubricator arm passes through. interestingly Don has both lubricator links going to the same pivot point on the drive arm, the prototype has two points on the drive arm giving a greater swing to the front lubricator? I could do this or follow Don, i'll make that decision much later, I haven't decided yet as to which lubricator is lubricating which part, something else to ponder over.


another thing missing from the drawings is the access hole/slot in the rear of the 2:1 gear stay for the middle cylinder valve connecting rod to attache to the 2:1 gear lever, So i removed the stay (hopefully for the last time) and drilled a suitable hole (easier than a slot)in the rear of the stay. Looking at the drawing for the 2:1 lever I took the distance from the pivot point to the position that the connecting rod fits onto the inner swivel gear ( my term here, I've forgotten it's name) which is IIRC 1 1/16 towards the frame side, the connecting rod doesn't seem to run parallel with the frame, I don't need to look at this yet. Picture shows the stay held agin on the right angle block.


i took this picture to show that the hole is where it needs to be, I've placed a length of 1/2 BMS bar in the steam chest and pushed through the 2:1 gear access hole, The bar is just resting on the bottom of the steamchest which isn't machined yet, so it looks lower than it would be in the 2:1 gear stay access hole.


A few pictures to show the end result of all this shenanigans.... picture from the top/rear. The cylinder and saddle are both bolted in place, it's getting tight around here, I wouldn't want to build to this design in 3 1/2 that's for sure..smiley.png One good thing is now that both parts are in place the height of the two blast pipes are much closer, so not much to remove if anything now. You get a better idea of the cut out on the back wall in this picture.


A view of the underside, I've placed a length of 1/2" bar in the piston gland to check/show the cylinder is running central for the crank.


still in checking mode, a side view to show that the incline is to drawing with the end if the bar being central for the crank axle.. I do like to double, triple check things..


Last picture for tonight of a general view, i have decided not to run the drain cock cables where I had first planned thinking after looking at some reference that they may sit much higher, I have placed a length of copper tube roughly were I'm thinking that they should be. This tube is probably twice the size required but I can easily get two pipe runs along here and down to the drain cock cross shaft under the cylinder with no sudden changes in direction. Note to self, I still need to cut away part of the cylinder lower center web for clearance of the cross shaft pulley'


The frames are nearly ready for paint, you may have noticed that i have removed the running board supports for the front side sections, the 2:1 stay is now loctited in place, I will remove the expansion links and I think that the frames will then be ready, once I have the paint/thinners. They need a good clean first and a little sanding to remove any score marks left over from all of the work that's been done on the., The cylinder/saddle will be removed and the area masked off so that the parts will still fit after painting with minimal damage to said paint.

She's getting there..smiley.png



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  • 2 weeks later...

vening guys

Weighshaft bearings for tonight, these are one of those many jobs that I have skipped and now need to catch up on, I have more photo's than usual for this update to try and show how I have tackled these. There's nothing difficult about them but they do involve a little thought in which sequence is best to machine them in, or should I say best for me and the tools that I have to hand.

They involve part turning and a little fabrication, Don specifies 'steel' for the bearings and silver steel for the weighshaft itself, I'll tackle the shaft another time. I have chosen to use EN8 for this job for no other reason than it's the only stock that I have large enough to do the job, in this case 1 1/2" bar. First picture shows a length being machined down to the required size of 1 1/4" which is for the mounting flange, the widest part of this particular part.


Next is to simply show that the bar was then cut into two sections approx 2" long, the length of the bearing is 1 17/32 plus 1/8 for the mounting spigot on the back to fit the frames, I will make this 1/4" as I have deviated from the drawings in that the hole in the frame is the same size as the hole in the expansion bracket, that being 1/2", iirc the drawing has the frame hole at 5/16" which is the dia of the weighshaft itself, this way I'll have the bearing going straight through the expansion bracket and into frames for extra rigidity.


Talking of 1/2", here I have rechecked that the frames are still square and that a length of 1/2" bar fits through nicely with no binding...i do like to check things..smiley.png


Back to the two lengths of EN8 now at 1 1/4" dia, I chose to begin first by machining the 1/2" spigot onto each ..


Simple picture to show that both parts fit into the frames/expansion link brackets nicely..


Next job was to step drill right through each bearing and finishing by reaming to the desired size of 5/16"


Then back to the frames and this time with a length of 5/16" bar to again check that all remained square with no stiffness..


I then needed to take care of the various mounting holes that hold the bearing in place, these aren't all on the same arc around the bearing as they follow the expansion bracket more than the bearing, as you can see i clamped each to the frames and transferred the holes into each, not the most accurate method but not important as the spigot does the job of ensuring the bearing sits in it's correct position, the bolts just hold it to the frames, for this reason I opened up the holes a little to make life easier during assembly.


with the holes marked I then drilled each by hand on the mill, letting the drill find the centre of each transfer mark...


things were getting tricky now as i had limited space for this setup, literally no more than a few mm to play with between hitting the chuck jaws and fouling up against the tailstock but we endeavoured and got through in the end. Picture shows the bar now reduced further leaving the 1/8" flange with the drilled holes showing, bar is now 19/32" dia and I have just taken the final cut across the flange face.


back to the frames again to check that the holes line up, as i said i opened them up a little to make life easier. the hole without a bolt is a bit of a strange one as from what i can see this is supposed to have a bolt but it's too close to the bar, interestingly the same hole on the right hand side ( as seem from the camera)is a csk bolt hidden under the bearing flange being part of the expansion link bracket mounting points, I would have thought this one would be too but not according to the drawings? I may just tap it and fix a bolt from the inside.


Last machining jobs were the taper and the 5/64" wide collar that sits on the tip of the bearing, The drawing shows the taper going the full length of the bearing from the collar up to the flange, I have stopped short by 3/16" which is the depth of the braces that need to be brazed on, this makes it easier to fabricate using 90 degree angles rather than odd angles to match the taper, I very much doubt that this would be seen anyway. I used a profile tool for this exercise..The drawing shows the collar as having a round section, I have left a flat edge as the prototype has an oil cap on this collar which I plan to replicate. I was a little surprised that there are no bronze bushes in this bearing, steel on steel seems a little strange to me but will hopefully help a little with the planned oil cap fitted.


Last picture shows the bearings temporally fitted and with the braces silver soldered in place, sorry guys but I completely forgot to take pictures of this stage. To cover the basics I cut 6 triangles from brass sheet,used 0.5mm silver solder wire, held in place with tweezers and brazed in place. I have given them a general clean up but they really need shot blasting to get into the web spaces properly. I have one job left to do and that's to profile the part of the flange that can be seen overhanging the expansion link bracket in this picture.


That's it for tonight, took me nearly as long to write the update as it did to do the machining...lol

more soon..



Edited by greenglade
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