Here is a list of all the postings Paul Lousick has made in our forums. Click on a thread name to jump to the thread.
|Thread: Boiler testers and material verification|
I'm not a layer, but if a boiler failed and the inspector could show that he did the checking and testing that was required by the model code and used the documentation supplied by you, that you would be the one that faced a claim. The inspector would also have to show that he was a competant engineer, capable of doing the job.
A reason to do everything as required in the model boiler code, keep records and have insurance.
Edited By Paul Lousick on 07/08/2019 10:23:45
Not all model boilers are the little toy Mamod type that are made from copper and opertate at 5 - 10 psi.
The boilers on a 7 1/4" gauge loco or 4", 6" traction engine have a boiler containing 20 - 50 litres of water and steam at 100 - 130 psi. These are a potential bomb if made from the wrong materials.
If I present some materials to a boiler inspector prior to building a boiler how does he verify that they are what my suppliers say they are ? The inspector can only go by the documents which you present to him and if you end up in court he will present these documents. It is then up to you to show a paper trail of receipts. Yes, a dodgy certificate could be printed or cheaper material substituted, which is a reason to buy from a reputable company and keep good records, otherwise you could go directly to jail, not pass go and not collect £200.
I supply a drawing of all of the boiler parts to the supplier when I order cut plates and the test certificate which they supply with the plates has a reference to each drawing.
You have to ask for a certificate from the material supplier when you place an order, otherwise there is no guarantee of the material that you receive and it would be a very fool hardy inspector that did not require one.
I have a test certificate for every piece of plate that I used to make my boiler and if any part should fail, it can be tracked back to the supplier and the manufacturer. My insurance would not cover me if I could not prove that it was made from the required materials.
A boiler inspector, especially a club inspector would not be able to accurately determine the type of material which you intend to use to build a boiler. As you have said, it would require a testing laboratory. The material surplier should give you a test certificate (not just a sales receipt) which specifies the chemical composition, tensile strength, etc for that batch of material..
|Thread: Most difficult part first|
As old mart says, it depends on your machining ability. If a beginner, start on something simple and not expensive to build up your skill level. Cheaper to make again if something goes wrong.
When starting my traction engine, a machinist who had built his own engine advised me to start on the wheels first as these were fairly straight forward and required a number of different skills. (Turning, milling, drilling, rolling plate, welding). They were also something which could be completed on their own and give me a sence of achievement.
|Thread: Graphite sealing cord|
If it is an antiquated bathroom basin mechanism with a gland nut, it probably used a graphite pump packing as a seal. O-rings are a later invention. Do a search on the internet or ebay. Graphite or teflon pump and valve packing is available in different sizes.
|Thread: Laser cut plates|
Laser cutting services use expensive machines and their charge out rate has to cover the cost of labour and business overheads and to cut a sample would be expensive. It's not just for cost of the material used.
Not many firms have a service where you could wait at the counter for a job to be done. Instead it would be scheduled into their work program and made at a later time after placing an order. Then you would have to come in and check the job and if OK, re-scheduled again for the final cutting. It is a different matter though, if you need hundreds of the same part and the cost of a sample part is justified.
Is there some way a laser cutter can do a dummy run to check? You would have to cut the plate to be able to check it. The laser profile cutter could trace out the path it would take to cut the plates without cutting but it would be imposible to measure.
In the days prior to laser cutting and CAD systems, steel plate was cut with machine with an oxy torch which traced the outline of a hand drawn template, drawn at a scale of 1:1. The finished size of the cut plates depended on how accurate a drafter could draw the profile with an ink pen, usually on plastic film which did not expand or contract like paper as it absorbed moisture. Steel plates could be cut with a 1mm - 2mm accuracy.
The advantages of doing everything in CAD (Computer Aided Design). is that the models and drawings can be drawn to a much greater accuracy. (eg. 0.00000001mm). Mating parts are assembled in the computer drawing and it is here that dimensional checks are made. Some CAD systems can automatically check for interference problems with mating parts. Much cheaper and easier to fix before it is cut from steel.
Most oxy, laser, water jet cutters use a computer program to cut the profile and if a CAD file is not supplied then someone at the cutting company has to make one. Some profile cutting machines have built in programs which can cut basic shapes without a CAD file but are limited to rectangles, circles, etc.
I had laser cut spokes made for the steel wheels on my traction engine and they were cut to within 0.2mm accuracy.
Edited By Paul Lousick on 01/08/2019 13:36:01
|Thread: Garryflex Blocks|
First I have heard of them. Are they worth getting ?
|Thread: Upgrading to fibre optic broadband|
I live in Sydney, Aus. and have no choice. My ADSL connection is closing and I have to change to fibre optic. They say I will get an evening download speed of 42 MB/s.
|Thread: Muncaster's Simple Entablature Engine|
Another question. This one about design layout. Why is the power side only supported on one side ie outboard and the valve gear is on a shaft supported between bearings? Ease of alignment? Simplicity to buid? So it can be seen easier? Nice engine, but design seems odd, to me. Even though I know there are umpteen small engines with no rear crank support.
The outboard crank design was also used on big engines, like the Case 150 HP road locomotive shown in this Youtube video
|Thread: Up and over door seal|
I have a panel-lift type door on my garage which is similar to an up and over at the bottom. Providing a water tight seal at the bottom of the door where it meets the floor is difficult. They are not precision parts and therefore not water tight.
To overcome the leakage, I made the height of the floor under the door about 10mm lower than the main garage floor with a slight fall to the outside. Any water that seaps under the door door is drained away.
|Thread: Chuck out of true|
From reading thru the posts, The backplate thread and register appear to be OK but have you checked if the backplate is running true when attached to the spindle ?
If the backplate checks out OK, the problem must be in the chuck and if cleaned and no swarf in the scroll, etc, then the jaws or scroll is worn and the jaws need a re-ground.
|Thread: Boring Head|
The minimum hole diameter is normally governed by the size of the boring cutter. Yor could possibley go smaller by making your own cutters. Also, the boring head can make much bigger holes by mounting the cutter in the side hole instead of the one at the base. They are very useful and worth the investment. Lots of useful videos on Youtube.
|Thread: Steam powered RC aircraft|
We do not hear much about steam powered aircraft for obvious reasons but I found this article which appeared in ME Vol 194, No 424 in 2005 and a Youtube video of its first flight.
|Thread: Making from castings or scratch build.|
Building from purchased castings is quicker but making something ftrom scratch is definitely more rewarding. It all depends on what you want to achieve. I am building a 6" scale traction engines and would have prefered to make my own patterns and make my own castings but that would be too much of a task. Its been a 7 year build so far.
Most of the accessories, lubricator, valves etc. have been build from scratch. This allows you to modify existing designs and give it a personal touch. It is also much cheaper than paying someone else for their work and definitely more rewarding.
|Thread: Another "what is it lathe"|
Thanks Neil, gives me a starting point to look for info.
Our club was given this lathe, much in need of some TLC and is missing a few parts. Does anyone know what it is and where I can find a user manual, drawings, etc.
Edited By Paul Lousick on 23/07/2019 09:11:16
|Thread: Why are CNC lathes more expensive than a CNC Mill|
Not sure, but CNC mills are more common than CNC lathes. The higher price could simply be because of production costs for smaller quantities.
|Thread: How badly do I need a surface plate?|
You can make your own surface plate for little cost and a lot of elbow grease useing the 3-plate method of lapping the plates. See link below. (other examples of this method on the web)
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