Clarkson 5" A3 Rebuild

[coniston]

So I thought I'd start a new dedicated thread for my work on rebuilding a Clarkson 5" A3. First a bit of history. This loco was built by Alan Fay of the Southampton society between 1969 and 1974. A picture reproduced below features on the front of the club newsletter in 1974 in steam ready for leaving the station at SSME track.





I bought the loco from Alan's son a couple of years ago, still complete and operating on air although the last boiler certificate expire in 1999. And here in lies the main problem and reason for a rebuild. The loco was originally built with a steel boiler so re-certification was creating an issue. Unfortunately the original shell test certificates were no longer available having been lost in various house moves, however I did have some of the more recent history. Speaking to boiler inspectors at both clubs I belong to (including Southampton) the conclusion reached was if I could get the original boiler tested by a professional inspector and passed they would be happy to carry out future re-tests. So I took it along to a RSA inspector who tests many traction engine and commercial miniature steam railway loco boilers. Prior to this I stripped the boiler out of the frames and took all fittings, regulator, super heaters off and hydraulic tested it myself to 200 psi just so as not to waste anyone's time. All looked good to start with, the inspector checked inside and commented on how clean and corrosion free it was. next he put the thickness tester on it and that was the problem. The boiler had been made using 10g steel for the firebox inner and outer, this is just not considered thick enough to compensate for corrosion under present guidelines so he had no choice but to refuse to test it. Bit of a bummer but in reality I was expecting to replace the boiler with a new copper one and had made consideration for that.


Wind forward 12 months and I had acquired a copper boiler ostensibly to the Don Young design but with some subtle differences, but at least it did fit the frames. Interestingly there is very little difference in dimensions between Don's Doncaster design and Clarkson's. The big difference is in the level of details and the lack of dimensions on the Clarkson drawings. Oh and Clarkson used slide valves whereas Don uses prototypical piston valve.


Any way I have finally cleared other projects and made a start on the A3, I have some posts in 'what I've done today' which I would love to move to this thread but don't know how, any help much appreciated otherwise please look there for the first instalments.

I'm adding the original posts from 'What I've Done Today thread in here: 

1. In the workshop on Sunday actually made a start at getting the new boiler into my Clarkson 5" A3. First job was to make a solid stretcher for the front foundation ring to sit on.



2. Making progress on my A3, made a smokebox ring to increase the boiler to inside smokebox size. Luckily a piece of 10g copper rolled up is just right. Judicial use of a file to get the joint nice and tight then fixed with 6BW CSK brass screws.



Next job is a new ashpan to fit the new boiler. After making a sketch I cut one from cardboard to check the fit. All seemed ok except it touched the rear truck axel. Second version fits nice.







So started cutting metal, I have some 1mm stainless which should be ok for this.



The original one has a hinged middle section, not sure I will follow that as it will be near impossible to clean out under the fixed side sections. My intention is to have the grate in 4 sections sitting either on transverse rods or angles. The bottom will be hinged to allow dropping ash and for disposing of fire.



Hopefully tomorrow I can get the bits cut out and start TIG welding them together.


3. Got another day in the workshop today and yesterday so progress is underway on the A3 ashpan. Mainly milling these to size so I can get them as accurate as possible to help alignment when TIG welding them. Made from 1mm stainless sheet.




Using my ER11 collet chuck which came on a ground 10mm spindle, held in the ER32 milling collet chuck, gets more clearance for the little 3mm throw away cutter.





Couldn't resist taping the bits made so together to check the fit, happy to report everything so far fits nicely.



4. Bit more on the A3 ashpan, got most of the bits made so stated on assembly, just tack welded together to start with. I bought a small, IIRC WP9, torch for my TIG welder, smallest I could get, along with 1mm tungsten electrodes. First time I used it today so I played around on some scrap bits until I got it about right. Much easier with this small torch for thinner gauge metal. Plenty of air holes so hope the fire will burn bright.





5. So today I have almost finished the ash pan, fully TIG welded, some good welds, others done by the overhead pigeons!!. I have made the ash drop door and fitted it using a short length of commercial stainless steel piano hinge, cut down to make it a bit neater. Currently temporarily fixed with 10BA screws and nuts, this will be rivetted finally. Only the door latch to make and fit and then onto designing a grate. Not sure to make 4 piece removable or fixed with hinge down centre part. The former will allow complete cleaning of the ashpan with a vacuum cleaner and brushes, the hinge down one will be fewer loose parts but the fixed sections each side prevent full access to the shallow 'wings' of the ashpan for complete cleaning.




At least it still fits, although there is some distortion I need to take out for a better fit.




And the hinged door being fitted.






Hope to finish off the ash pan tomorrow and scheme out the grate.


Chris D

[Deleted]

This is great Chris...a lovely loco with lots of history, thank you for sharing. I for one will be following your progress eagerly..
Not sure if you can move posts but if not why not just copy and paste them across so at least you have them all together. You'll probably have to add the pictures seperately but that won't take long.
I'm very much looking forward to further updates..

Pete

[coniston]

I forgot to add these photos taken the day I collected it. Most people may know the A3's were mostly named after famous racehorse, mine carries the name Blenheim and BR number 60087. My intention is to get her up and running then sort any issues before stripping for a repaint in LNER green. I just don't think they look as good in BR green, personal but there you go.








Chris D 

[keith1500]

Well, she looks pretty good in this livery.

I’ll be following this one too. Good call.

[kipford]

Chris
Welding is not bad, I have seen a lot lot worse. By the way where did you get the hinge from?
Dave

[coniston]

Today, I finished the ash dropping door latch. I fitted a brass handle just for fun, to make it I slotted a piece of 1/4" brass with a 1/16th slot drill, then drilled and rivetted it to the embryo latch. in the lathe I turned it to shape then parted it off. The rest was all done by hand. Latch is 1/16th Stainless steel.







That's the ash pan pretty much finished other than riveting the door hinge and latch bracket in place of the 10BA screws.

Chris D

[coniston]

Apr 2, 2020 7:32:20 GMT kipford said:

Chris
Welding is not bad, I have seen a lot lot worse. By the way where did you get the hinge from?
Dave

Thanks Dave, the hinge came from a previous employer out of the scrap bin when they did a redundant stock clearance. Couldn't resist having a couple of 1m lengths, knew it would come in handy for something LoL. I think RS sell it but you can probably get it else where.

Chris D

[springcrocus]

Apr 2, 2020 7:32:20 GMT kipford said:

Chris
Welding is not bad, I have seen a lot lot worse. By the way where did you get the hinge from?
Dave

Dave, I might have misunderstood but search for "piano hinge" if you need to get some. Apologies if you knew this and meant something else.

Regards, Steve

[WetHeader]

Hello Chris,

She certainly looks a beast. Look forward to see how it all goes and seeing her down the track again one day.

Tom

[runner42]

Hi Chris,

down under we would say "half yer luck" to have acquired a magnificent locomotive and a copper boiler. In UK speak a jammy b*gger. Look forward to seeing your progress.

Brian

[coniston]

Not a great deal done today, I found the back edge of the frame of the ash pan where it joined the short vertical part had warped during welding. So I cut through the weld with a Dremel cutting disc, clamped it back straight and re welded it. Then finished the ash pan by riveting the hinge and latch bracket in place. Then onto the grate, after checking a few dimensions and making a couple of sketches I have decided to make the grate in 4 pieces, each will have 6 firebars 3mm wide with 4mm gaps, this fits neatly into the dimensions. Having the grate completely removable will allow better cleaning and if I need to I can replace the grate sections at any time without lifting the boiler.


Luckily Metal Supermarket in Southampton are still open for phone or online orders, so I managed to pick up 2 off 2.5m strips of 3mm stainless cropped to 12mm wide off of a sheet. Being cropped off a sheet they were a bit twisted, more like propellers!

Twisting it in the vice with a toolmakers clamp got it out quite easily, certainly good enough to start with.



Photo of before and after, if you can make it out.




So I cut 26 pieces to 145mm long as the embryo bars, two are spare.




I started making the 4mm spacers, need 40 of them, but now I having a rethink and may use 12mm lengths of 4mm round between the bars and weld them together, still not sure yet, have to  think about it overnight. It would save drilling all those holes and parting off all the spacers.



Chris D

[coniston]

Well I thought overnight and remembered what I used on Dad's grate for his 7 1/4 Hunslet 'Elidir'. I used M5 stainless steel nuts over 4mm stainless rod. Checked the width an they are a shade under 4mm so just about right and no need to make the spacers.


First job was to drill the bars. I milled one end of each bar square as a datum then I marked one out and set it in the drill vice, lined the end of the bar with the end of the vice jaws using the butt of a square and moved the vice to line it up with the centre drill, then clamped the vice to the table. Centre drilled each bar at one end, lining each one with the end of the vice jaws made them close enough to the same position on each. After each was centre drilled they were then opened out with a 4mm drill.




Each was marked with a hacksaw on the edge set against the fixed jaw so I could ensure they aligned on the rods , needed to do this as the material was cropped from sheet so the width wasn't exact on each.

I then set them in packs of 6 on a 4mm rod and having marked one bar off at 100mm centres I set them in the mill to drill the second rod hole. Toolmakers clamps each end held them together.





A 3.5mm 5% cobolt drill was used to drill through all 6 pieces then they were opened out to 4mm. Drilling stainless is ok if you have a sharp drill, a little cutting oil and keep the pressure on so the bit doesn't rub, but cuts all the time, don't be too tentative is my way.




Before separating them I marked a diagonal line with a permanent marker so I knew which order to keep them in after separation, just in case the hole went through not quite perpendicular.



A quick check that all 4 grate pieces fitted together with the M5 nuts, and onto the next operation.





Next up was to bring the pieces to length and mill an angle on each end so the ends are vertical as the grate sits sloping forward. I didn't bother making the grate with a bend in it to follow the foundation ring as it is set up into the firebox a bit and I considered it just wasn't worth the effort, I'd probably end up with them all different anyway. 
The angle calculated at 5.85deg. so I used an inclinometer to set the pieces (again in their respective blocks of 6 pieces) in the vice. 



 Then milled the angle on the one end I had already brought to length, then milled the other end to give an overall length of 5 1/2".



Last operation was to cut the rods to 44mm long and put a short M4 thread on each end for M4 retaining nuts. This will need to be changed as two nuts next to each other on adjacent grates make too big a gap. Really should have thought of that earlier and I could have offset the rods on adjacent grates, have to think of another fixing method or just grind each nut down to just under 2mm.

Quite pleased with the result so far though.



And laid into the ashpan just for effect.



Tomorrow I will have to sort out the fixing nuts to maintain the correct gap, then make the fixing angles for the grate to rest on. Hopefully that will then complete this bit.

Chris D

[coniston]

Not so much progress today as I'd hoped, but I did get the angles cut down from 20mm x 20mm x 3mm stainless angle to 3/8" x 3/8", bit of old fashioned hacksawing then trim to size on the mill.


Then I notched each end of the grate sections so they will sit on the upturned angle edges therefore locating them fore and aft, width location is purely by the fit of each section to each other, needs to be a bit sloppy so they don't bind up after a bit of heating from the fire. Just a couple of photos tonight.




And this I show they sit on the angles. The angles will be supported on spacers above the ash pan.




Chris D

[coniston]

Not a great deal more so far, I have fixed the support angels into the ashpan and reduced the thickness of the nuts on the ends of the rods so all the grate pieces sit together with the right gaps. Hope to get on and do a bit more tomorrow.





Chris D

[coniston]

Final update on the grate, I have got all the pieces to fit in the firebox, it took some more adjusting of the lengths of the bars as there are some stay heads inside that they fouled on. Glad to report they all fit and slide easily side to side so getting them in and out should not be too much of a problem. I will have to make a special tool that fits between the bars to get a better grip than the long nose pliers I have so far used. Pictures taken looking into the fire hole. 







Not sure what is next, maybe the superheaters and header, or start at the regulator and work towards smokebox?

Chris D

[Deleted]

Excellent job Chris...

Pete

[simplyloco]

Grate work Chris!

[don9f]

Hi Chris, I find that cranked “forceps” work well for lifting the grate sections out through the firehole. I can take a picture if needed, but you may know the type I mean, where the jaws are serrated and the handles lock together.

Cheers Don

[steamer5]

Hi Chris,
Nice grate.....one suggestion, well 2 actually.

I should have thought of this earlier..... you my want to consider a a center spacer bar to stop the bars warping. This then leads on to the 2nd idea....

My Dad installs his grates thru the fire hole door as well. His grate is in 3 sections & slightly shorter than yours, he has 3 spacer bars, the middle one is in the center, he made a tool to install & remove the grate, a simple length of suitably thick wire that’s an easy fit thru the fire bar gaps, a file style handle one end & a “U” formed in the other end ....facing up....id get a photo but lockdown is preventing visits other than dropping groceries off .....keeping the U as close to the horizontal wire as possible. Makes getting the bars in & out easy. Hope that makes sense

Cheers Kerrin

[coniston]

Thanks guys,
Don,yes I have a pair of those which I have used but maybe they're a bit small as the weight of the grate slips through the jaws, although so far that is what I have been using.
Kerrin, good idea about the third spacer rod, probably not too difficult to add that, and I understand what you mean about the tool, sounds simple enough.

Chris D