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Member postings for Roger Best

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

Thread: Steam wagon "Meg" advice, please.
22/08/2020 00:06:28

I don't know about the rules but I would suggest that the cylinder is a structural component because it sustains mechanical load as well as pressure.

Thread: Which one to build
21/08/2020 23:39:30

John - how important is picking it up? Do you need to carry it into the house?

Also how big is your garden - they have a dreadful turning circle?

It may be that a too-heavy engine can be made acceptable by using a lifting frame or device.

I have had a bad back most of my adult life and can probably lift more now than at any time in the past twenty years so I am very aware that bending down to lift 20kg+ is not a good idea.

These guys have the right idea - I have visited their factory and seen their kit. Something to pick an engine up onto balloon wheels would take a small effort compared to all the work in the engine.

https://youtu.be/F4QXG5cvNSc

Thread: Brian's 1" Minnie Traction Engine
21/08/2020 23:13:27

smiley Great thread - you have covered a great many issues over the years.

Fabulous work Brian!

Thread: Mamod safety valve
21/08/2020 21:28:22

You are more than welcome, not a new idea though.

Here we go: smiley

You can do a lot worse than copy Kevin:

https://www.ita-shop.co.uk/ourshop/prod_5496551-Mamod-14-BSF.html

https://www.ita-shop.co.uk/ourshop/cat_1283563-SAFETY-VALVES-cc-pg_2.html

Thread: Copper boiler plate flanging, or not?
21/08/2020 21:18:28
Posted by Paul Kemp on 21/08/2020 20:09:10:
Posted by Roger Best on 21/08/2020 15:03:45:

sad Bob - send it straight back to Reeves as not fit for purpose and quote your rights for internet purchases. They should be responsible about this sort of thing, you are paying for a competent technical service.

My thoughts are if anyone thinks a model engineering supplier is giving a competent technical service to a degree they are in la la land where they are selling "drawings" with no manufacturing tolerances and many littered with dimensional errors!

The other issue raised by Dave H is there is no UK constructional code to underpin the model test code to give the inspectors any definitive guidance so you are reliant on the experience and knowledge of the individual inspector and any reference they make to commercial standards.

That said, I do think the "system" as it stands is fit for purpose as if it wasn't there would be boilers exploding left right and centre, insurers would be going bust under the claims, premiums would be rocketing and officialdom would be clamping down hard on the hobby!

If we ignore the hysterics of model boilers are bombs, will distribute shrapnel over many metres if they fail and look at the facts, miniature copper boilers are pretty safe and even one constructed to mediocre standards is very unlikely to fail catastrophically. Probably the most likely failure on a boiler likely to cause injury is poor threads on fittings allowing the fitting to be blown out. I have witnessed the failure of a back head to wrapper joint on a commercially made boiler as it happens which was entirely unspectacular bar the cloud of steam in the cab and the loco coming to a halt. It certainly didn't explode violently and the copper tear itself the shreds!

We should not be cavalier about these things for sure and every effort should be made to ensure as far as possible they are safe but we also should not instill in ourselves and others an illogical fear and suspicion.

Paul.

Its nice in la-la land Paul! cheeky

If the design has been updated then they should sell material for the updated design. Its not difficult. Bob wants the safer design so he is allowed to return the goods.

Equally if they are selling certified material they should control the material certs properly; its why certified material is expensive. If you are saying they can't do either competently then shout louder as there will be a lot of boiler certificates that aren't worth wiping your butt with.

Selling a photocopy of someone else's copyright material is not relevant to this issue.

Thread: Mamod safety valve
21/08/2020 20:25:10
Posted by martin perman on 25/06/2020 14:49:00:

Gentlemen,

I was given A Mamod TE1A Traction engine for my Birthday when I was fourteen and forty two years later I want to refurbish it, I would like to make a new safety valve, I am aware I could buy a new one but I have the means and ability to make and test one, the operating pressure is 10 - 12 psi, my only problem is how do I calculate the spring required and again I could measure my old one but then I learn nothing.

Martin P

Edited By martin perman on 25/06/2020 14:50:36

Edited By martin perman on 25/06/2020 14:52:02

Don't bother calculating it Martin. smiley

Instead make the valve adjustable my having a threaded stem (towards the end) with two nuts. This is how some other manufacturers made theirs, Fleischmann comes to mind I think.

Find yourself a nice stainless spring out of a pen and give it a go. If its a bit soft you may have to look around a bit but it is likely you will find it works fine.

There are far too many parameters to design a Mamod SV without encountering tolerance problems; with a little adjustability you can be spot on.

Thread: Is a hand scraper pulled or pushed?
21/08/2020 17:22:37

I have only seen it done, not done it, but I am sure the answer is push, like wood chisel.

have you tried Youtube?

Thread: Copper boiler plate flanging, or not?
21/08/2020 15:03:45

sad Bob - send it straight back to Reeves as not fit for purpose and quote your rights for internet purchases. They should be responsible about this sort of thing, you are paying for a competent technical service.

Agreeing with Duncan - a design has failed if there is any distortion. There needs to be a margin between load and resistance to cater for wear and tear, in this case erosion and mechanical fatigue. That margin is established by a proof test at above working load.

Some design codes allow minimal "set", lifting beams for instance, where there is some stress re-distribution. This is OK in a simple structure that can easily be examined and shown to be undamaged, a locomotive boiler is a lot more complex than an I-beam with a few holes in it, how can you tell what is happening deep inside without an awful lot of work?

The other issue with distortion is buckling - the point at which the shape is so distorted that its strength is no longer adequate. Fortunately a very large amount of development has gone into the locomotive-type boiler and copper is wonderful stuff, so it tends not to be a problem, but in principal if its stretched it won't be as designed and will be weaker than intended.

Thread: Who trains these ideots?
18/08/2020 20:46:38

I think the country is going to pot for the same reason.

Anyone with a brain and in independent streak used to do a trade where they could be their own boss. A good apprenticeship meant they could be trusted on their own.

For many years now the brighter and more industrious sort have gone to University. Leaving the rest, including all the wasters, snowflakes etc, who would have been fine in heavy industry being supervised, to cause chaos in domestic situations. Meanwhile the grads get the life sucked out of them by the corporate world.

We are doomed.

Thread: Copper boiler plate flanging, or not?
18/08/2020 16:33:24

Not much on YouTube.

The 2" version is pretty big, I would say it would easily pull a man. The 1" would need some advantageous conditions, good flat surface, good bearings on the cart etc.

I have seen some tiny engines move a big load, its all down to leverage at the end of the day, tinker with the gears and it comes good.

18/08/2020 16:21:50
Posted by Phil H1 on 18/08/2020 15:31:24:

Can I ask a question about Minnie please? It has a remarkably small boiler (page 3) - hence the name I guess but what can it realistically do? e.g., on a really nice flat surface, can it pull the driver or do you run it like the little Mamod traction engines using a long control rod?

Phil H

I am pretty sure they will pull a man of reasonable build. Any on YouTube?

18/08/2020 14:51:15

angelthumbs up

18/08/2020 11:21:05

Is the edge used to fix the model in space?

Thread: Faircut lathe tidy up
18/08/2020 11:16:59

smiley I love the golf ball.

There is a club down the road, they tend to knock them out of the grounds.....wink

Thread: Which Milling machine and what is its footprint?
17/08/2020 22:02:40

cimg9188.jpgcimg9189.jpg

17/08/2020 21:59:31

smiley

Hi guys

A Warco 16B has been ordered, along with some bits and bobs to get me going. Its pretty small in the flesh, very quiet though. Warco's showroom is amazing.

The bench is all but complete. Ironically after all the effort and discussion, a mistake on the Warco website might mean that the drip tray might overlap the bench edge, but everything is about compromise so I didn't change my mind at the last minute. I have done a video that just needs the last bits done before publishing.

Thread: Copper boiler plate flanging, or not?
17/08/2020 21:42:47

As an owner of numerous toy engines I can confirm that Duncan is right about " one mistake with water level and your boiler was ruined".

Thread: Copper mig wire and boilers etc
17/08/2020 21:17:33

TIG is the craftsman's tool for small, non-ferrous metal, The arc acts like a flame allowing a variable, even intermittent deposit of filler metal. Mig is adjustable, but relies on a rate of delivery, so better for a continuous run, but challenging for tricky welds. I have done a lot of Mig welding on cars and the corners always suffered for my lack of skill.

Welding is a great way to make scrap.

Thread: Battleship Grey
31/07/2020 23:15:59

Its fashionable smiley

Thread: DRO installation - a salutary lesson
31/07/2020 23:15:04

frown interesting lesson Bob., So capacitive slides are as fussy as optical? I might start saving for the posh ones.

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