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Member postings for Dave Smith 14

Here is a list of all the postings Dave Smith 14 has made in our forums. Click on a thread name to jump to the thread.

Thread: Solid Edge - Community Edition
12/10/2021 14:10:45

Dave

I did say in a limited way. I agree with 2D data that there are compatibility issues with fonts, drawing borders etc but the important bit which is the geometry does not normally have problems. It does not take long to recreate dimensions add a drawing border any way. With 3D models on the 'good' CAD systems 3D model transfer is not a problem. I transfer models between CATIA, SE and occasionally F360 without any issues. The first photo shows the boiler for my Aspinall which was modelled in CATIA, the second photo shows the boiler assembly after conversion to a STEP file and then imported into SE which took about 5 mins Depending on the system and how you create the STEP file it can be made to bring all the parts in their correct relative position.

So for Ian this may be useful to know if he needs to import a complete assembly.

I was not advocating people use multiple packages, just answering a question if systems can talk to each other which they can. I would always advise if possible to chose a CAD that does what you want of it and stick with it.

By the way I have used CAD systems continuously since the early 1980's where I was involved with the introduction of the first system into Rolls Royce, Computervision CADDS 3 if anyone remembers it. I then went onto to use CADDS 4, CATIA V3, V4 and V5 which is my current weapon of choice.

catia.jpg

se.jpg

12/10/2021 09:14:42

All the 'good' CAD systems can talk to each other in a least a limited way. This is either achieved using native translators embeded in the software or importing geometry using dxf for 2D and either IGES or STEP for 3D. STEP is the preferred file format for 3D. As Paul says with regards to 3D geometry you get a 'dumb' solid. This means it has none of the history as to how it was created, as this is unique to the parent software. However a dumb solid can be modified, have materials allocated etc you just cannot deconstruct it and it is still orrientated correctly relative to its origin axis. So although parts in an assembly may lose their relative positions, it is an easy task to reposition them. (I have the tee-shirt on a full model of a 5" gauge loco). STL files are not designed to be modified as such and are difficult to manipulate, some CAD systems have functions to change the mesh to a surface model, which in turn allows a solid model to be created (CATIA has this function).

Thread: Transporting 5 inch live steam loco
11/10/2021 18:49:53

This is what I use. It is simple scissor frame pivoted onto the lower frame and upper frame at one one. The other ends have sealed bearings run along the upper and lower frames. A car scissor jack provides the movement to raise and lower the upper frame and is arrange to give around a 2:1 motion ratio. No fancy machining needed, cheap to build, does not take up a huge amount of room and the loco can live on it in the workshop or garage which at present my Super Simplex does. If you want some more detailed photos let me know.

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Edited By Dave Smith 14 on 11/10/2021 18:52:30

Thread: Charatan motors
07/10/2021 07:45:03

Ron Laden's Class 22 build thread will help you a lot as it discusses the choice of motors, batteries etc.

Class 22 build

Also look at the photos of this Charalatan Station Road Steam had for sale. It shows how the drive train is arranged.

Station Road Steam 08

Thread: origin of CAD
10/09/2021 14:06:52

For anyone interested a fairly comprehensive history of the origins of CAD.

Table of Contents: CAD History

Thread: How concentrated should I make a citric acid pickle ?
26/08/2021 18:20:18

I bought a 5kg bucket of it from Ebay for about £10.

Thread: Galatea help
19/08/2021 18:35:27

Daniel

Also worth asking the same question on the Model Engineering Clearing House forum, which tends to have a lot more locomotive based people posting than here.

Thread: Design Award
18/08/2021 09:58:37

Why do so many model engineers knock anything that does not conform to the norm? I think it is a nice elegant piece of design, that has a practical use and if that is the value of the prize good on him, because it will pay off a huge amount of his university debt. Remember we are talking here about product design (he will probably go onto to design white goods) not mechanical design which is a whole different ballpark.

Thread: Filling the boiler
15/08/2021 13:48:37

Caravan water pump (about £7 on the net) through the blow down? That is what I use on my Super Simplex and other clubmates do.

Thread: Steam oil
14/08/2021 18:38:37

I use Morris's steam oil in my Super Simplex, available from Heritage Steam in either 1L or 5L containers.

Thread: Aluminium
20/07/2021 14:31:08

As a professional user of Aluminium (40 years of aircraft structures) I stand by my opinion. The OP wants to make a seat base. It will be subject to loads from the occupant. Strength may not be issue, but is very low at 100 - 135 MPa (mild steel is around 240 MPa) but stiffness is going to be important and we talking about structure that needs to be SAFE. 1050 is extremely soft so yes suitable for things like foil, lables and custom dashboards but not where its operating environment will subject to any significant loads, which a person sitting on a bike can easily apply.

Bill I agree 5251 would also be a good candidate.

Also remember that with all Aluminium welding the HAZ at the joint unless heat treated will be in 'O' condition. So with say 6082-T6 with a tensile strength of around 295 MPa the strength at the joint will be in the order of 65 MPa and very soft, so stiffness can remain an issue.

Dave

19/07/2021 08:53:49

1050 is no use for anything except foil and labels being pure Aluminium. 3103-H4 or similar is a better bet as it is weldable relatively easy to form and has a higher strength. 6082 can be used but you will need it in the fully soft T0 condition.

Thread: Fusible plug in a 5" gauge copper boiler?
09/07/2021 19:20:06

Paul..

Always happy to oblige with hornets nestsdevil. Thanks for the update.

08/07/2021 07:37:48

Paul

Copy of the whole page. We will go with your version as it makes more sense at our scale. Also It does not matter to me as I only use it as a guide, although a very good one.

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07/07/2021 13:47:00
Posted by Paul Lousick on 30/06/2021 14:46:22:

Hi Dave, Your extract from the model code is not exactly correct.

I checked with my copy of the AMBSC code for copper boilers, Issue 8-2012 which I believe is the latest edition and it states in para 5.7.1 that: "If used, fusible plugs shall be fitted in the highest point of the inner firebox crown that is readilly accessible for plug replacement" and not shall be fitted. So it is optional.

5.7.2 The clear area thru any fusible plug shall be equal to 20% of the area thru the safety valves, with a maximum bore of 4mm diameter. (The pressure valve orifice diameter is taken a Nomogram diagram)

Paul

Paul I am very confused extract from my copy of issue 8 - 2012? This copy came from a fellow club member so I am not sure where he got it from.

ambsc.jpg

29/06/2021 13:29:38

Just looked at the current version of AMBSC, para 5.7 which states that a fusible plug SHALL be fitted and makes no concession for diameter, which means it is mandatory on all boilers. It also states the fusible material shall be commercially pure tin, I read this meaning solder with at least 99% tin (eg lead free solder) and leaded solder if you still have some not being allowed.

Thread: Cold blue for Aluminium?
27/06/2021 18:16:14

Birchwood Casey Aluminium black. £16.50 on Ebay.

Dave

Thread: Ideas on how to make a nylon Stiffnut 'less stiff'
06/06/2021 10:28:19

+1 for run it up and down a bolt it will soon loose its grip. That is why repeated use of nylocs should be avoided.

Thread: Complete novice in Hampshire
25/05/2021 08:56:30

Jerry

I live in Cowplain and am building my first 5" gauge loco a Don Young Aspinall. I have a Warco WM250V lathe and a. WM16 mill. If you want to pop round and see what I am doing pm me.

Thread: Who uses airbrushes?
23/05/2021 14:00:39

+ 1 for the Iwata Neo. A good easy to use brush that is not expensive. I spray enamels, acrylics and cellulose with mine quite happily. I use airbrush cleaner at the end of each session to clean out before taking it apart to final clean in an ultrasonic cleaner. It will spray large areas but it takes some time because the need as Jason says to maintain a wet edge. The 63" wingspan Hurricane in the photo was painted with it. Although the paint is semi matt.

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