What Did You Do Today 2021

[John HinkleyParticipant @johnhinkley26699]

Having had the overnight period to think about what I wrote above re. the encoder drive, I realise that I need to clarify the statement about the spindle and output shaft speeds being dissimilar.

Although strictly correct, what is more accurate is to say that the output shaft rotates at a different rate to the spindle although at a fixed ratio, irrespective of the gearbox speed selection. Otherwise it would make a nonsense of the thread cutting gear change wheel combinations! The actual ratio is nine revolutions of the spindle to two of the output shaft. So I can fit the encoder to the output shaft after all (via a belt drive) and juggle the reduction in the maths part of the program. I could have saved myself a whole bunch of work if I'd thought about it even longer! Back to the drawing mouse.

John

[Nigel Graham 2Participant @nigelgraham2]

Had a Feeling Bad incident…

I've accidentally killed one of my garden frogs!

Lying on the floor, head through the worshop door and under the front of my steam-wagon where I was re-fitting the front axle after a modification, I noticed something on the bottom of the door jamb, about 18 inches from my face.

It took me a few moments to identify it as a small frog.

Post-mortem showed cause of death to be traumatic conversion from isometric to orthogonal body shape. Inquest concluded it had been there, unseen by me, when I'd turned the workshop lights off and closed the door late last night, trapping the animal against the jamb.

Scooped it up with the 17mm spanner I had in hand, put it under a nearby bush, and reflected that I must be more careful on completing late-night engineering sessions, but at least it would have been an instant death.

RIP, little amphibian.

[Anthony KnightsParticipant @anthonyknights16741]

I found myself at a bit of a loose end while waiting for some paint to dry, so I decided to investigate 3 LED lamps, which failed recently. I cut the frosted plastic bulb off and saw this inside.

The miniature switch mode power supply is obviously beneath the panel carrying the LED's and connects via the two pins on the white connector towards the centre of the board. When powered up, I found that measuring on the + and- pins of the connector, one lamp read 1.2 volts and the other two, about 110 volts. With the LED boards removed from the lamp assembly, I was unable to get any resistance readings through any of the LEDs.

I then took the board from the lamp with what I assumed was the failed power supply and fitted it in one of the lamps with the 110 volt supply and BINGO, it worked. Not much of a sample I know, but out of 3 lamps, two had faulty LED arrays and one had a faulty power supply.

If I had taken a bit more care when cutting them open,I could have glued the now working one back together and had a free lamp.

[Speedy Builder5Participant @speedybuilder5]

Of course Nigel G should have had door opening training with the relative assessment before being allowed to control a door.

When I was at work, I had to report 2 accidents. One was where one of my lads tripped over his own wellington boots whilst walking down a corridor – apparently there was a footwear training course which he was subsequently sent on (Which did not include wellington boots) and on another occasion, my secretary put a staple in her finger (No course available for that) and I seem to remember that the accident report was mysteriously lost – By my secretary!

[Nigel Graham 2Participant @nigelgraham2]

"Door opening training"… Ah, in this case the fatality was due to door closing.

Blow me, when I opened the workshop door this afternoon, there was a frog sitting on the floor immediately inside, staring up at me! They aren't easy to pick up without risking injuring them, so I chivvied it to hop gently outside and into a safe area. It had most likely crept in when I previously had the door open.

I did once have a genuine door-opening near-miss. It was at work, or at least on work duty, and I should probably have reported it. Driving somewhere on a work trip, I stopped at a service-area. It was a windy day, and as I opened the door to resume the journey a gust of wind caught it, jerked it out of my grip and rammed the very corner against my forehead. Half an inch lower and it would probably have had my eye out.

[Kiwi BlokeParticipant @kiwibloke62605]

Nigel, sorry to hear the frog croaked…

OK, OK, I'll go and do something useful.

[Nigel Graham 2Participant @nigelgraham2]

I suppose someone had to say it, Kiwi……

[BufferParticipant @buffer]

Stood back and admired the axle horns riveted onto my frames. What a relief to get that all done.

Opps!

Edited By Buffer on 06/07/2021 12:18:53

[Roger BestParticipant @rogerbest89007]

[Nigel Graham 2Participant @nigelgraham2]

You know what they say…

He who never made a mistake, never made owt!

[Nigel Graham 2Participant @nigelgraham2]

Own project – continuing fabricating my 4"-scale steam-wagon's ash-pan.

The club's steam loco – refitting its narrow bunkers after a service, presented the very fiddly task of inserting 4BA cheese-headed screws though their internal base angles. Casting round for something to hold the screws after struggling with pliers, such as stiff wire to make a crook, I spotted an oddment of bamboo from the garden.

Two cross-cuts with a hacksaw and there we were, and it worked: a screw-head collet made from Chinese grass!

[Anthony KnightsParticipant @anthonyknights16741]

Aye up Boss, I've finished with the red lead primer.

And a grand job you've made of it. I reckon that'll do!

[David George 1Participant @davidgeorge1]

Wife decided she would like a new door knob for newly decorated hall cupboard door. Some thing Art Deco was the gist. So made this.

In good books for a while.

David

[Anthony KnightsParticipant @anthonyknights16741]

Today I took delivery of a 500 gram reel of "proper" 60/40, 1.2mm cored solder. Its for use on PCB's and I don't know if it's me or my soldering irons, but I just cannot get on with the crappy lead free stuff. It looks like it may get some use straight away as this week, one of my laptops has a non working screen and yesterday my disability scooter refused to go. This might get expensive.

[Bill Davies 2Participant @billdavies2]

Anthony, if you've had your irons for some time, you will need to replace them. The lead-free solder melts at 34 degrees higher temperature, and older iron may not get there. Especially a problem if you are soldering parts that conduct a significant amount of the heat away.

The lead-free solder also doesn't freeze with the nice shiny surface that suggested a good joint had been made using the lead-tin solder.

Bill

[Kiwi BlokeParticipant @kiwibloke62605]

Posted by Anthony Knights on 16/07/2021 10:21:29:

… I just cannot get on with the crappy lead free stuff. …

You're not the only one! It keeps the electronics repair people in business, however, being responsible for far more solder joint failures, and other problems, than 'proper' stuff. Rather than tooling up to try to use the 'orrible stuff, stick with Pb-containing solder, and buy a lifetime's supply, while you still can.

Useful tip, should anyone need to de-solder a Pb-free joint, say to remove a failed component on a (modern) pcb. Add Pb-containing solder to the joint before sucking or wicking. It will increase the solder's fluidity and lower its melting point. May need to do it more than once. And if you're a masochist, hand-soldering SMDs, I think Pb-containing solder is the only way to go.

[Anthony KnightsParticipant @anthonyknights16741]

Posted by Kiwi Bloke on 17/07/2021 02:30:09:

stick with Pb-containing solder, and buy a lifetime's supply, while you still can.

That's why I've just bought a 500 gram reel. I did get it from a UK supplier, but it's labelled "Made in Taiwan", so it looks like another product we don't make any more.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Kiwi Bloke on 17/07/2021 02:30:09:

Posted by Anthony Knights on 16/07/2021 10:21:29:

… I just cannot get on with the crappy lead free stuff. …

You're not the only one! It keeps the electronics repair people in business, however, being responsible for far more solder joint failures, and other problems, than 'proper' stuff….

Quite amusing, there's a moan in one of my 1940's A5 sized Model Engineering magazines that proper tin solder was replaced by 60:40 rubbish as a war economy, and the cheapskates never fixed it.

In practice, the alleged unreliability of tin solder joints seems greatly exaggerated. Going back 20 years, much concern was expressed that lead free solder would increase the problem, but at that time there was no understanding of what caused whiskers to form and it was assumed lead in solder reduced the effect. Later research suggests lead-free solder is innocent, or at least much less whisker forming than feared.

My life is full of electronics, and – so far – I've never seen a failure caused by growing tin whiskers. Dry joints, electrolytic capacitors, corrosion damage, resistors changing value, static electricity, water, tired fuses, insulation damage, cracked tracks, tracks lifting off the board, yes. I'm not saying tin whiskers don't exist, or that high reliability electronics can't use lead, but lead leaching out of landfill into the water supply is a serious problem. Irresponsibly dangerous. Not because hobbyists use a bit of 60:40 solder, but because industry make billions of electronic boards every year. In 2000, about 80000 tons of lead solder per year. Anthony's 500g reel isn't the problem, it's the other 160 million!

And Anthony needs a new soldering iron. Tin solder is difficult to use if the iron isn't hot enough. So is 60:40!

Dave

Edited By SillyOldDuffer on 17/07/2021 11:27:09

[SamsarandaParticipant @samsaranda]

Dave you mention that the problem with lead is that it leaches out of landfill into the water supply, I was under the impression that current landfill sites had to be located such that there could be no contamination of water supplies to the extent that a number of recent landfill sites have been constructed with a non-porous membrane as a foundation expressly to protect from contamination of water supplies. The mind boggles at what sort of nasties could be dissolved in our drinking water. Dave W

[modeng2000Participant @modeng2000]

Dave, I have suffered the problem of tin whiskers. The OC170/171 transistors can have this problem.

The whiskers grow internaly and can produce shorts between the four connection wires.

One remedy is to mechanically shock the case to fracture the whiskers or another way is to fuse the whiskers.

I ordered some replacement transistors and these had already whiskers!

John

[Brian HParticipant @brianh50089]

I've been cutting some Iroko wood to turn some pulleys for the 1896 Ford model that I am making.

Not for nothing is it known as ironwood. It's very hard.

I'don't use much wood but when I do I go to Nottingham Hardwood Timber who supply small pieces for pencil makers, model makers, furniture makers and even boat builders.

**LINK**

Wood Turning/Self-select Timber Store

I have absolutely no connection with this (largely one-man) business other than as a very satsfied customer.

Brian

[SillyOldDufferModerator @sillyoldduffer]

Posted by modeng2000 on 17/07/2021 12:25:21:

Dave, I have suffered the problem of tin whiskers. The OC170/171 transistors can have this problem.

The whiskers grow internaly and can produce shorts between the four connection wires.

One remedy is to mechanically shock the case to fracture the whiskers or another way is to fuse the whiskers.

I ordered some replacement transistors and these had already whiskers!

John

Gosh – how old might an OC170 be? This Philips spec is dated April 1958. No wonder the poor things have grown whiskers, ho ho!

This picture (pinched from VMARS, July 2008) shows whiskers inside a transistor:

Note the two short whiskers are growing from the can towards the lead; the phenomenon seems to be more associated with smooth tinplated surfaces rather than solder joints.

A transistor of this age would have been soldered with 60:40, not high tin.

If whiskers were a major problem I'd expect a high failure rate with SMD boards – the inter-pin gap of chips on these look less than 0.2mm and there are thousands of them in a laptop. So far so good, but I wouldn't bet the farm on it. Maybe they will all fail over the next 20 years!

Talking of whiskers, I've never grown a beard or moustache. Is that a record?

Dave

[Roger BestParticipant @rogerbest89007]

Whilst lack of facial hair is unfashionable at the moment it not a record no never have had any. I believe its common among the majority of people.

[Robert ButlerParticipant @robertbutler92161]

Are we excluding the fairer sex, quite a few have have significant facial hair!

Robert Butler

[Joseph Noci 1Participant @josephnoci1]

Posted by Brian H on 17/07/2021 15:56:45:

I've been cutting some Iroko wood to turn some pulleys for the 1896 Ford model that I am making.

Not for nothing is it known as ironwood. It's very hard.

I'don't use much wood but when I do I go to Nottingham Hardwood Timber who supply small pieces for pencil makers, model makers, furniture makers and even boat builders.

**LINK**

Wood Turning/Self-select Timber Store

I have absolutely no connection with this (largely one-man) business other than as a very satsfied customer.

Brian

Mmm, not true….Iroko is also known as African Teak or Nigerian Teak, definitely not Ironwood – in fact, there is no such thing as Ironwood, or an Ironwood tree…Poor usage of the term has resulted in any wood heavier than water being termed Ironwood, but there is no botanical wood named such. Iroko is native to the North African West coast and only resembles Teak – it is not Teak…

And, Iroko floats on water..

Dad was a Master Cabinet Maker, so I have saw dust in my Blood..

Joe

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