Member postings for Dave Smith 14

Nigel

Any 3D CAD system can create a hollow cylinder like you asked. Here is an example with flanges added at both ends as well. All done with a single 2D sketch which you can see in the picture.

Ask the same question on RMweb you are more likely to get more response.

RMweb

Dave

Luker

Similar to you I used FEA on ME boilers. First photo a section cut through the FEA on a steel version of the Highlander Boiler. I did this as a favour for a member of this forum and wrote a full report which used 3 justifications, first principles hand calculation, a comparison with the Aussie code and the FEA. This was done before not long before I retired and I had my Chief Stress Engineer do the a peer review on the FEA methodology and results as a check. The FEA showed up some issues with design as presented to me and allowed me to easily modify the design to eliminate the problems.

I am also building a Don Young Aspinall. I have modified the boiler to remove the crown girder stays of the original design and replace them with crown rod stays. The boiler design was checked to see if it complied with and then modified in accordance with the Aussie code, how ever I also carried FEA on the boiler as designed and modified to for rod stays. The FEA results were quite interesting. The crown girders are very benign with reasonably low stress. However the some of the crown rod stays when designed in accordance with the Aussie code guidelines were marginal and needed to be increased in diameter to get the levels to a point where I was happy with them. The change to stays has been cleared with our BI's to the Aussie code but they are aware that the FEA has initiated further modification and fully endorse it. Little steps, but I am lucky in that one our BI's is a retied professional engineer like myself. Second picture is from the Aspinall FEA.

Over on MECH, this thread details painting a Stirling.

Stirling Single

Duralac is the yellow conformal coating used to protect interfaying surfaces in a lot of Aerospace applications. The permanent joints on my tender and loco chassis are using it.

4 Years into my Aspinall class 27 build, I have a complete tender, chassis running on air, smoke box and all plate finished and a most of the boiler parts made but not assembled. Nothing is final painted yet. So what is my advice at this point. Do your research and built what you want to, which is what I did. A 4-6-2 Pacific is no more difficult to build than my Aspinall just a few more parts to make. Laser cut anything you can, you can break complex parts into layers which can be silver soldered together. Only use castings where you have too, for a lot of items it is easier, quicker and a lot cheaper to hog from bar. I bought a complete set of casting (in a sale) but the quality was very poor and the tender axle box castings were not fit for purpose and binned. Boiler, your choice I am making mine. Oh and enjoy the process it can be very frustrating at times but ultimately very stimulating.

Nigel

To echo Jason's comments, if you go for a low end machine you could be running into trouble as you get more proficient and model sizes increase. CAD systems are very memory hungry and need high end graphics cards and lots of RAM to run properly. My laptop is now 4 years old and has a quad core i7 processor and 8 Gb of ram. The graphics card is an INVIDIA GTX1050 Ti. I find this only just copes with the full 3D model of my Aspinall Class 27. I am considering changing my laptop as I have a damaged case, one screen hinge has broken and the battery is knackered and I will go for 16Gb ram this time and upgrade the graphics. I expect to pay at least £1K for a new machine to give me the power I need. I could probably get it cheaper using a tower system, but the laptop suits how I use the machine. I use a firm called Novatech for all my machines, they are a local independent manufacturer to me based in Porchester Hampshire.

In summary go for the most powerful system you can afford/are prepared to pay for.

Owl castings.

Metal Casting | Owl Castings | England

Steve

Get a copy of the Australian Boiler Code, AMBSC. Part 1 cover copper boilers. If you work to that in conjunction with your Boiler Inspectors, you should not have a problem. If you want a copy of the code PM me with an email address.

Yes.

Stew

PM me your email address and I will send you some info I have which explains the process very simply.

Dave

I am involved at the moment in changing the status of the model railway club of which I am chairman and is currently a non incorporated organisation. The main reason for this is that our landlords are moving from a service letter agreement for our room rental, to a commercial tenancy. We have decided change to a Company Limited by Guarantee, having considered changing to a charitable status for a couple of reasons:

1 We are bunch of people who build model railways, we do do not anything which 'benefits the community' as charitable status requires you to do.

2. We have substantial assets and if the club is dissolved then the assets are distributed amongst the members. This is not permitted if you are a charitable trust, the assets must be passed to another organisation to use.

3 We think it is easier to take the potential hit on taxation of any profit than the additional hassle that goes with being a charitable trust brings.

We will classed as a micro entity which makes the annual accounting much simpler and does not require the accounts to be audited under the small company rules.

Acetone or IPA.

Dave

I am 6ft and have Warco stand. Height is fine for me. Without a stand I would set it at kitchen worktop height.

My experience with the castings on my Aspinall is unless they are lost wax from a known set of dimensions, I would only use castings if it there was no other choice (like wheels). I would either fabricate or machine from solid. For sure on my next loco that is the approach I will be taking.

There is a study that found Parsnips contain carcinogens! How many of us have stopped eating them. Seriously provided you use a suitable mask and disposable gloves, with the quantities you are probably spraying something else is going to kill you first.

Bob

Yes you just push the rail through the roller. Can be done by one person or with help. It is large scale version of this. The rollers are spaced relatively further apart though.

Make a base from plate, thick sheet or even wood about 400 mm long. Get three bearings about 20 mm OD M8 bolt. Bolt two bearings to the base at the ends of the plate. The centre bearing needs to be positioned centrally between the two outer bearings such that its position can be adjusted in the transverse direction. Place rail between the three bearings and adjust to put a gentle curve into rail. Run the full length of the rail through the bearings and it will put a curve into the rail. Continue adjusting until desired radius is achieved. If you over bend just reverse the rail and adjust it out. We use a rail bender like this at our club.

Phil

The joint is basically as per Don Youngs drawing. The only change I made was to the outer wrapper to include the little 'ears' that line up with boiler tube flange. The throat plate is double flanged, hopefully this picture will explain the joint, note the bottom of the throat plate and the wrapper have not yet been trimmed to length.. If you want more detail let me know.

I used plywood for the flanging on my Aspinall and 3D printed formers for outer and inner wrappers, which work a treat. I have also used a 3D printed former successfully to reshape one part when I got plywood shape wrong.

Hope the following photos may be of interest to some people.

First couple of photos show the 3D formers.

This photo shows the laser cut and 3D printed drill jig I made to get all the bits in the right place.

Where I am

Trial fir in chassis.