Don Young L and Y Aspinall Class 27 - Not Midlands

[kipford]

Pete
Forgot in my notes above that the boiler is being run at 90psi in lieu of 80psi and all the Aussie code and FEA work was carried out based on that pressure. The BI's suggested increasing the pressure to give a bit more headroom when running.

The CAD model been a great bonus, as I know that within machine limits the shapes of the formers, positions of components conform to what has been modelled. This allows things like the drill jig to be quickly, accurately and cheaply made using rapid prototyping techniques. Mind you it will inevitably walk a bit when we solder it up.
Dave

[Deleted]

Oct 18, 2021 12:45:23 GMT kipford said:

Pete
Forgot in my notes above that the boiler is being run at 90psi in lieu of 80psi and all the Aussie code and FEA work was carried out based on that pressure. The BI's suggested increasing the pressure to give a bit more headroom when running.

The CAD model been a great bonus, as I know that within machine limits the shapes of the formers, positions of components conform to what has been modelled. This allows things like the drill jig to be quickly, accurately and cheaply made using rapid prototyping techniques. Mind you it will inevitably walk a bit when we solder it up.
Dave

interesting Dave... does your boiler use longitudinal stays or not, I'm not sure what volume this covers. My boiler for 4472 does not have them following the Aussie code for long boilers using stronger butted tube plates, 6mm vs 3mm, IIRC shorter boilers may still use stays under Aussie rules but can't recall the full details?

Pete

[kipford]

Pete
I have two longitudinal stays running from the backhead to the front tube plate. The stays are threaded into bushes silver soldered into the shell and are type two stays as defined in para 3.4.3 of the Aussie code. The code allows type two to be used in any length of boiler providing the stay length is less than 100 x stay diameter. Type 1 which is a simple rod silvered soldered to the shell my on be used at 40 x stay diameter. There is a type 3 palm stay which is attached between vertical surfaces and the shell/wrapper at a max angle of 20 deg to the shell/wrapper. Not sure I understand your stronger butted tube plates?
Dave

[Deleted]

Oct 18, 2021 15:13:45 GMT kipford said:

Pete
I have two longitudinal stays running from the backhead to the front tube plate. The stays are threaded into bushes silver soldered into the shell and are type two stays as defined in para 3.4.3 of the Aussie code. The code allows type two to be used in any length of boiler providing the stay length is less than 100 x stay diameter. Type 1 which is a simple rod silvered soldered to the shell my on be used at 40 x stay diameter. There is a type 3 palm stay which is attached between vertical surfaces and the shell/wrapper at a max angle of 20 deg to the shell/wrapper. Not sure I understand your stronger butted tube plates?
Dave

From what I understand, in place of the longitudinal stays the tube plates front and back are doubled up from 3mm to 6mm by joining two 3mm plates together on the upper section where the stays would normally be. I understand this to be for long boilers where the stays are too long to actually do anything...
Something like that, as I said, I am very much a layman on boilers.

[kipford]

Pete
OK that is what I thought you meant. I need to think about this one.
Dave

[kipford]

CAD is great, works brilliantly provided the nut driving is not going bananas! Tried the boiler shell in the loco this afternoon. Funny the backhead is just clipping the edge of the rear hornblocks! Check of drawings and CAD model show that I had actually forgotten to shorten the boiler model as described earlier, hence the drill jig and wrappers are to the original length. What a walley. So back in the jig with a couple of 3mm spacers and things are now where they should be.
Dave

[kipford]

She is starting to look like a loco!

IMG_3169 by Dave Smith, on Flickr
IMG_3170 by Dave Smith, on Flickr

Dave

[Midland]

Hi Dave
Looking good. I am not going to make my boiler for lots of reasons that Steve and I discussed today. I will watch with interest how yours comes together and perhaps learn a little from that.
Cheers David

[kipford]

Little bit more progress. Firebox is bolted together and I have now started on the boiler tubes. After a lot checking of the dimension of the front plate of the firebox assembled in the boiler shell relative to the front tube plate, I was happy to start on the superheater and flue tubes. The reason for so much checking is that i am machining a 0.25 mm deep shoulder on each end of the tubes to keep them in position when soldering similar to what Steve (Springcrocus) did. The photo shows the two super heater tubes and the first of the flue tube finished and trial fitted. Another 15 flue tubes to go. That is tomorrows job. 

IMG_3180 by Dave Smith, on Flickr

Dave

[kipford]

Well all the tube fit, so onto the bushes.
IMG_3184 by Dave Smith, on Flickr
Dave

[kipford]

ast couple of days efforts.
Finished the boilers tubes. So I was able to check the position of the firebox and tubes were correct, which luckily they are. I 3D printed some cones like Springcrocus made to make lining up the tubes easier. Great things 3D printers for little gadgets like these, 15 mins on the CAD then go and do something else while the printer chugs away. I then made a doubler plate to go around the dome hole in the boiler tube. This is to put some section back into tube where there is a large hole. Then made the dome bush, I will drill and tap the holes after it has been attached to the boiler. Finally made a selection of bushes required for the various fittings, there are more to go. They included the water gauge bushes which were trial fitted to the backhead.

All the tubes in place
IMG_3193 by Dave Smith, on Flickr

Doubler plate, dome bush and sundry others
IMG_3194 by Dave Smith, on Flickr

Water gauge bushes in place
IMG_3195 by Dave Smith, on Flickr

Dave

[kipford]

There probably will not be any updates for the next 6 weeks as my wife came out of hospital yesterday after a hip replacement last Monday. So I am now full time carer for a while and modelling time is going to be severely limited. Also as Chairman of the South Hants Model Railway Club I am helping to prepare for our fist club exhibition in 2 years on the 20th November. If you are in the area please come along as it promises to be a good show. The link is to the exhibition page of the club website.


SHMRC Exhibition details


Dave

[Midland]

Dave
Best wishes to your wife. Janie has had two new hips, they heal quickly, she will be mobile before you know it.
Cheers David

[jcsteam]

Dave your CAD work and loco building to date are top notch. I like seeing the methods you employ and been a late comer to this thread have been having a read through
. I was wondering if I may have a copy of the drawing for the riding trolley. I've been looking for one to build in 5" and this looks bloody good! I know there's a lot of laser cut parts, but I am mainly looking for overall dimensions to work from.

I hope your wife recovers well from the operation.

[kipford]

PM me an email address and I will send some drawings do you want the GA and piece parts or just the GA. Also PDF or DXF format.
Dave

[Midland]

Dave
Re discussion today about blown down on the boiler. Where exactly did you put the blow downs? Did you need to make a new hole through the frames for them? Would not the one in front do. My boiler man wants to put it at the back but I do not see how one would access it!
Thanks
Cheers David

[kipford]

David
There is not enough room at the rear of the boiler to access a blow down valve, due to the proximity of the rear axle and the reservoir for the hydrostatic lubricator. Don's design has a single blow down at the front of the firebox, but it is a blind access and I am concerned with the possibility of burns from escaping steam. So I have decided to go with two side mounted blow downs. They need holes through the side frames which are not prototypical and need to be as small as possible to minimise the loss of section in the frame. Picture shows the layout. I can give you more details if you want. At present I am about to make the bush's for the blow downs and drill the holes, just have to do the dome bush hole first.
Dave

Blow Down Valve by Dave Smith, on Flickr

[Midland]

Thanks Dave big help. Hope to show you a boiler in a couple of weeks!!
Cheers David

[kipford]

Coniston and I spent the day persuading about £100 of silver solder to go all the right places. Like Steve and Wilf before us we are both boiler virgins so this is a voyage of discovery. After discussion with the BI's the idea was to do all the high temperature solder joints today. So the plan was to start with the firebox wrapper and tube plate. Then progress to the boiler barrel/outer wrapper/throat plate at the same time doing the doubler plate for the dome hole and the brackets inside the boiler tube for the injector water pipes. Then finally to put all the bushes in the back head.

Solder was Cup Alloys 438 in 1 and 1.5 mm dia rods.

For heat we mine and Chris’s Sievert torches with a variety of nozzles and my oxy/propane kit. I have a 19kg propane bottle with a twin outlet manifold so we were able to ring the changes as required between two propane torches or propane and oxy/propane.

Pickle was Citric Acid in a small container for the firebox and back head and an old plastic dustbin for the main boiler assembly. I have (did) a 5 kg container of Citric acid (courtesy EBay), its really cheap so we made up a couple of batches of new pickle to take advantage of using hot water. It was mixed at the CIP Alloys recommendation of 20g/litre.

We were very pleased with how things went and just hope the BI’s agree, as we need to get these bits inspected before progressing any further.


Firebox assembly. We would have done this in a single heat but, forgot to do the tails of the tack rivets, then at the end we decided to fit the bush for the fusible plug as well. The first heat was done using two propane torches, but the second and third were done using a propane torch for background heat but using the oxy/propane for the rivet tails and the fusible plug bush to keep the heat to minimum in the main joint.


The boiler tube/outer wrapper/throat plate required three heats as well. The first heat soldering the main joint from the outside saw solder penetration through all the joint however it was marginal in places, but we were encouraged by the result, we also successfully did the water tube brackets. We tried the dome hole doubler, .however the flux was exhausted and we did not get full penetration. The BI’s had recommended a second heat applying solder from inside the wrapper if the penetration was not full which is what we did next. For the second heat we using thermal blanket inside the boiler tube and a big 80Kw burner as the we were needing a lot of heat to get the boiler up to temperature. We only did the main joint on the second heat and were pleased with the result. The third heat was done using the big burner for back ground and the oxy/propane to finish the double for the dome hole.


The back head for the Aspinall has bushes on both sides of the back head, so we used some strong backs I had made to hold in place the bushes on the inside the of the back head. This also took two heats as the blower and regulator bushes did not fully penetrate. The first heat was two propane torches, the second was propane and oxy/propane. We did manage to silver solder the bolts holding the bushes in place into the bushes, but this is not difficult to fix.

We did not have time to take many photos, but here are a couple.


Photo 1. Ready for flux and soldering.


image2 by Dave Smith, on Flickr

Photo 2. The soldering set up.
image3 by Dave Smith, on Flickr



Photo 3. The fire box after a short time in the pickle and the main boiler cooling ready for pickling both after their first heat.


image1 by Dave Smith, on Flickr

Photo 4. The result of the days work.
image5 by Dave Smith, on Flickr



Dave

[uuu]

If your journey follows the way Steve's and mine did, you'll find you get better at arranging the thermal blocks etc, and it won't take as much heat to get things up to temperature as at the start. Even though the boiler gets bigger and heavier. We used extraordinary amounts in the beginning, and seemed to take longer than the later heat ups. Perhaps the open nature of the early shapes allows it all to escape.

It looks very promising.

Wilf