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Member postings for duncan webster

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

Thread: Oxy hydrogen torches
22/05/2019 19:01:13

There are companies who don't charge rental on bottles, you pay a deposit (returnable) then just pay for refills. Depends where you are.

Thread: Warrington Model Engineering Developments
22/05/2019 16:27:08
Posted by duncan webster on 19/05/2019 13:14:37:

WMED ceased trading a long time ago, next time I'm up at the club I'll ask if he is still this side of the Styx, provided I can remember of course

The guys name is Harold Pugh, he hasn't been a member of our club for many years, but is still listed in the phone book at Wilson Close, so might be worth a phone call. Just put a 2 in front of the number shown in the previous links/pictures. He must be getting on a bit though.

Thread: Cast Iron For Boxford Change Gears?
21/05/2019 13:26:44

If you must have iron, then I don't see why you'd need SG iron, ordinary grey cast would be strong enough. You don't mention the finished diameter, but I'd pay the supplier to cut 2 pieces 1/2" thick rather than risk trying to cut it yourself.

Thread: stamford show vandals
21/05/2019 11:35:47

So do you want to live in a country which is hardly a functioning democracy, and scores 4 on a scale of freedom rating (7 is worst, 1 is best). UK rates at 1, same as Germany and Netherlands, slightly higher than France which is 1.5

Thread: Loco hand pump casting from Reeves
21/05/2019 11:24:20

Tender hand pump is in the water space, so a bit of a leak doesn't matter, it just goes back where it came from. Of course no good reason not to fit O rings in the rams

Thread: Larger VFD/Motors
20/05/2019 18:26:25

I used to have an MCB in the supply to mine, more often than not it tripped when I switched the vfd on. On the advice of an electrical engineer I know I fitted a fuse (15A if I recall), no further trouble and it is several years ago. It is a proper distribution unit fuse, not the one in the plug. the workshop distribution box is fed from the main house box via a 30 A MCB (normal domestic type), this has never tripped due to workshop issues

Thread: stamford show vandals
20/05/2019 13:26:22

Around half of people released from prison will re-offend within a year. Doesn't say much for the effectiveness of prisons does it. Persistent criminals in Holland are ''given two-year sentences and tailor-made rehabilitation programmes. Fewer than 10% then return to prison after their release". The Dutch prison population has fallen by 43% in the last few years, at the same time crime has fallen by 25%. We lock up nearly 3 times as many people per head of population. What we need is more effective policing so that miscreants are caught, followed by proper supervision/training during probation/prison. UK has 208 policemen per 100,000 population, Holland has 381. We privatised out probation service so that profit became more important than rehabilitation.

More stats, prisoners per 100,000 population UK 140, France 104, Germany 75, Holland 61. I know politicians don't like to base their decisions on evidence, but it is pretty clear to me that we need a rethink, prisons as we run them clearly don't work.

Corporal punishment just shows offenders that violence against the person is acceptable, not quite the message we are trying to get across.

I will now get off my soapbox, and retire to the workshop.

Thread: The Chocolate Fireguard as designed by Mercedes Benz
19/05/2019 19:07:39
Posted by V8Eng on 18/05/2019 00:22:19:

I read recently that EV charge points installed using a Government grant will have to be “smart” in the very near future.

I have just found the article again so add a link.

Charging points

Does that imply that when the wind isn't blowing (no wind generation), or it's dark (no PV) you won't be able to charge your car?

Thread: Warrington Model Engineering Developments
19/05/2019 13:14:37

WMED ceased trading a long time ago, next time I'm up at the club I'll ask if he is still this side of the Styx, provided I can remember of course

Thread: Natural gas for TIG welding
17/05/2019 21:35:23

Sif bronze melts at about 885 C which is a lot hotter than the silver solder most of us use. Let us know how you get on, as I've got a bundle of Sifbronze rods somewhere

Thread: Class 22 Diesel (next project)
17/05/2019 20:58:11
Posted by duncan webster on 17/05/2019 18:01:03:

400 Watts from a loco doing 8 mph (3.7 m/sec) is a tractive effort of 108 kgf. The best coefficient of adhesion you can rely on is about 3 (less on ally rail) so best make your loco weigh at least 325 kg, which is a hell of a lot. 108 kgf is enough to pull a train weighing over 5 tonnes up a 1 in 100 slope even allowing for rolling resistance.
I'd just settle for less power, say 200 watts. Even the Lionel Flippance machine in Dave's link only managed 300 watts average.

OOPS, sums wrong! Having a bad day, or at least that's my excuse

tractive effort is 108 Newtons, not kgf, so the weight only needs to be 33 kg, which is much more manageable. Max load up a 1 in 100 will then be 550 kg, about 7 people plus the loco

Edited By duncan webster on 17/05/2019 21:02:47

Edited By duncan webster on 17/05/2019 21:31:45

17/05/2019 18:01:03

400 Watts from a loco doing 8 mph (3.7 m/sec) is a tractive effort of 108 kgf. The best coefficient of adhesion you can rely on is about 3 (less on ally rail) so best make your loco weigh at least 325 kg, which is a hell of a lot. 108 kgf is enough to pull a train weighing over 5 tonnes up a 1 in 100 slope even allowing for rolling resistance.
I'd just settle for less power, say 200 watts. Even the Lionel Flippance machine in Dave's link only managed 300 watts average.

Thread: aching ribs - posture
16/05/2019 21:53:02

I have a small vice bolted to a steel plate which I grip in the normal vice for fiddly fettling jobs. It has smooth jaws so no need for soft jaws and is a lot higher up than the normal recommended elbow height, so no stooping. Just remember not to slacken the wrong handle to get the job out of the little vice, or you finish up with sore toes.

Most lathes are mounted too low for me as well, I find that cross slide handwheel at navel height s about right

16/05/2019 21:53:02

I have a small vice bolted to a steel plate which I grip in the normal vice for fiddly fettling jobs. It has smooth jaws so no need for soft jaws and is a lot higher up than the normal recommended elbow height, so no stooping. Just remember not to slacken the wrong handle to get the job out of the little vice, or you finish up with sore toes.

Most lathes are mounted too low for me as well, I find that cross slide handwheel at navel height s about right

Thread: DC Treadmill Motor
16/05/2019 10:27:23

If John is correct and it's wound field with 3 wire connection you'll need to do some surgery to find the other end of the field winding, otherwise you won't be able to reverse it. 1.3kW is very much overkill by the way

Thread: 5" gauge LSBC Minx
14/05/2019 19:27:12

There was a thread some time back from a guy copying all LBSC designs into 3D CAD. Might be worth contacting him to see if he's done Minx

Dean Da Silva

Thread: The Chocolate Fireguard as designed by Mercedes Benz
14/05/2019 10:10:24
Posted by Samsaranda on 14/05/2019 09:36:27:

Colin, I await the debut of an electric Caterham 7.

Dave W

Well there is already a Isle of Man TT race for electric bikes, a bit spooky seeing seriously quick bikes which make no noise electric TT

Thread: Adjustable workshop perching stool
13/05/2019 16:53:05
Posted by Jim Nic on 13/05/2019 14:10:44:

Looks very useful Stew, is that a lavatory seat you have on it? I manage with an assortment of 3 stools but not having the kit or expertise to weld I shall have to continue doing so.

Jim

I don't think it's meant to be that multipurpose, there's no where for the bucket!

Thread: Steel boiler storage.
13/05/2019 14:54:10

There was a very good article in ME by Silly Old Duffer not long back which went into prevention of condensation.

As Paul says, after blowdown, even if you get all the liquid water out, the boiler is full of hot air saturated with moisture. When this cools down a lot of this moisture will condense onto the internal surface, just what you don't want. To get corrosion you need both liquid water and oxygen, so filling the boiler to the brim with de-oxygenated water would seem lie a good route, if you have copper tubes then de-ionised as well sounds good to prevent bi-metallic corrosion. This however does nothing for the external surfaces, a boiler full of water will have a large thermal inertia and so changes in ambient air temperature and humidity could result in condensation on the outside. Is this a problem?

In my working life I came across similar problems, we finished up tenting the item and blowing in de-humidified air. I believe this is the solution used by SS Great Britain, although their problem is worse because of the presence of chloride ions, see SS Great Britain

SOD's article went on to describe a control system which would switch on/off a dehumidifier as needed, you only want it when the dew point of the air is above the temperature of the steel. I think you could use a heater to warm the steelwork , but then you'd need insulation.

To summarise, if it were mine I'd build a reasonably air tight storage box for the whole engine, put a dehumidifier inside and build one of SOD's controllers. A halfway house which should deal with internal corrosion is to dehumidify the inside down to some level where the dewpoint is below anything it will actually see, and then fit the dessicant breathers I mentioned earlier

Thread: Brazing torch
12/05/2019 14:33:31

In similar vein I recently got a bunsen burner, the idea being that I could use it for little jobs like boiler fittings and save having to get the propane bottle out. Useless! Does anyone know of a burner that will work off mains gas and generate enough heat to silver solder boiler fittings etc. I'm not talking Flamefast size,

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