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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: What did you do today (2015)
10/11/2015 17:45:25

I spent about 2 hours trying to find the fault in some Arduino softawre, and eventually found it was a hardware problem, blown transistor. Don't you just hate electronics, at least if something mechanical breaks it's obvious

Thread: Todays update from Bodgers Lodge
10/11/2015 17:36:56

Surely 'modern' and 'harley'; constitutes an oxymoron

Thread: A new small lathe on ebay from China.
09/11/2015 20:47:13

It's a clone of the Super Adept!

Thread: Tracking the sun's movement
06/11/2015 12:54:28

Ok pgk, here's your challenge for today! Use your array of photocells to find the sun, measure the angle from north, input the equaton of time and drive an LCD display to give a digital sundial!

Thread: What did you do today (2015)
04/11/2015 20:46:22

And as for hydrogen powered cars producing no pollution, where do they imagine the hydrogen comes from? Most of it is made by reacting methane with steam, so you start with water and methane, convert it to carbon dioxide and hydrogen and then burn the hydrogen to get water. That's supposed to be better than just burning the methane to get water and carbon dioxide.

There is however one way of making the whole thing work, use wind power to generate electricity which you then use to make hydrogen by electrolysis of water. At least you can store hydrogen (not easily but possible), and if the wind hasn't blown for a bit you can run your car off petrol.

Thread: Warco 250 cross slide dial slipping
03/11/2015 12:31:03

Sounds like your lathe is not fit for purpose. Have you contacted Warco? In principle you can demand your money back, but other people I know have had good after sales from them.

Thread: Unimat 3 Vertical Head Quill
02/11/2015 16:43:03

I've probably got a copy of the article in the attic if you're interested.

Thread: Motorcycle General Discussion
01/11/2015 22:50:55

I think they eventually got round to making the rocker box part of the head on the very last Triumph twins, which must have helped a lot, no longer had the push rod forcs opening the joint. It only took them 40 years!

On my Velo you were supposed to set the tappets with the engine hot, but you had to take the tank off to get at them, so you had to take it for a thrash, then whip the tank off quick!

01/11/2015 01:32:59

I was supposed to start as a graduate apprentice with BSA Triumph in September 1971. I was made redundant before I started! However when I went on the 3 day interview I found that they had solved the problem of new bikes leaking oil all over the showroom floor, they drained it out before shipping from the factory! The Bandit/Fury was only an updated 3TA, still a 2 bearing twin, granted very fast, but as the Honda twins of the time had a four bearing crank built like a brick outhouse (got to be polite on this forum!) it's not dificult to see why the Japanese wiped out our motorcycle industry, we gave it away. Pre war designs still being made in the 1960s. Yes they had gone unit construction, but basically the same, and still spending money tinkering with 2 designs which competed against each other. I reckon the BSA twins were actually better than the Triumphs, but I'll now go away and wash my mouth out.

Thread: BSA C15 upgrade to 12v electrics
31/10/2015 12:18:58

You only have to dump power if you allow current to flow in the first place. With clever electronis I'd have thought you could have it full wave rectifying up to a battery voltage of say 13V, then half wave recitifying up to 13.5V, then switching off completely. Battery has very low internal impedance so should mop up any ripple. Have I just re-invented the Honda system?

This is similar to how the old dynamo regulators worked, above some voltage the field current was reduced, all using a voltage sensitive relay.

30/10/2015 22:25:45

55W halogen on a 100cc bike! I had 25W on a Velocette Venom, which would just about get to 100mph. Any more flatenned the battery as on a good day that was rated at 28W. Real men don't need to see where they are going!

On a more serious note, te big Zenner shunt always seemd more than a bit crude, couldn't some kind of switch mode arrangement be developed? I probably don't know what I'm talking about as they usually step up, but why not controlled step down?

Thread: Valve Gear Simulator Software
30/10/2015 17:13:54

To make Bill Hall's valve gear programs run fully on Win7 I had to use Dosbox. Don't ask me how to make this run on a MAC, I guess you need a dos emulator.

Without dosbox the programs would run but could not access or amend saved data files

Thread: super Heaters
30/10/2015 00:11:16

I have a copy of Bill's later paper if anyone is interested send me a pm and I'll try to find it.

30/10/2015 00:00:57

For the definative answer see **LINK**

After these tests Bill replaced the LBSC type superheaters in his loco with radiant type and then sleeved down his water pump as the loco used so much less water and therefore coal.

I accept that coaxial type don't work as well, but I don't yet see why. Transfer of heat from the hot to the cold steam can't be the answer because that would not affect the energy gained from outside the superheater system. If the hot steam flowed down the outer annulus I'd believe it lost heat by radiation to the cold flue tube (hot and cold are relative here).

Thread: LED mark space
29/10/2015 12:38:29

I'm always amazed by the knowledge of people using this site, and how helpful they are. I've found an article (ME 2009) about using a lens to make the apparent diameter of the light bigger, and to make it more directional, so I'm going to experiment with this and pulsing. As the whole thing is driven by a microprocessor pulsing is software mods, so quick and easy. The built in routine for pwm runs at <1kHz so I'm not anticipating RFI. As an amusing aside I once worked on a plant which had a high power RF heating system. We were asked by 'the management' to prove that we weren't interfering with everyone's radio, so I consulted a chap who had worked for the BBC for advice. He advised me to tune a transistor radio to Radio Blackpool (the nearest station to our operating frequency) and wander round our site and the local area to see if there was a problem. No fancy tests or meters, I like solutions like that. I'll let you all know how it goes, but once again thanks to all who have replied. At least I now know why the green gives up first.

 

By the way Neil, I can't make the present red LEDs dimmer as they have a bult in switch mode power supply, if you reduce the input volts the current goes up (steeply) and the brightness stays the same until you reach a very low voltage, when it just gives up the ghost. I'm not planning on using these in te new manifestation!

Edited By duncan webster on 29/10/2015 12:38:56

28/10/2015 18:51:56

I'm on with a low battery alarm, but I confidently expect the drivers to ignore it, after all they ignore the fact that the green LED has died without mentioning it (the green LED array seems to give up the ghost first). We're also looking into a solar panel. SillyOldDuffer's link looks just the ticket, thanks. I'll post the rsukts, but don't hold your breath, need to wait till running season is over before undertaking any major rebuild of the unit.

28/10/2015 17:14:55

A little bit off metal bashing, but of relevance to our signalling system. I've got all the gremilns out (famous last words), the usual cause of failure is now flat battery (no-one seems to remember to charge them up). I've read somewhere many years ago that turning an LED on and off very rapidly reduces the power cosumption, but hardly reduces its apparent brightness. Tried google to no avail. Anyone got any info on best mark space and best frequency?

Thread: THE 2016 MODEL ENGINEER EXHIBITION
28/10/2015 17:10:24

I'd missed the significance of Appleby Parva, centre of population of UK. Obvious flaw, it's outside the M25, so southerners will either deny it's existence, or be too afraid to attend.

27/10/2015 19:47:05

Why not come clean and rename it the South East Exhibition. Three and a half hours travelling for me and I'd still only be at Weybridge station. I've never bothered since it left central London, stick to Harrogate (Doncaster) and/or Midlands

Neil if you think BH is a long way from the centres of population I suggest you invest in a map! It's a lot nearer to the conurbations in the North and Midlands than Weybridge is.

Edited By duncan webster on 27/10/2015 19:49:43

Thread: Elf n Safety police
26/10/2015 15:53:18

Agree totally with Neil. If properly conducted risk assessment stops you doing something, you shouldn't be doing it in the first place, unless you want someone to get hurt of course. If it stops you doing something which isn't unsafe, it hasn't been properly conducted, do it again.

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