James May: The Reassembler

Hello viewers,

I'm James May and this is The Reassembler,

the show where we take everyday objects in their component form

and put them back together very slowly.

That feels very nice. Oh yes, look at that.

It is only when these much loved and iconic objects

are laid out in hundreds of bits...

Oh man in heaven.

And then slowly reassembled

that you can truly understand and appreciate how they work...

Total rubbish.

And just how ingenious they are.

It's good isn't it?

And if painstakingly putting

hundreds of pieces back together again...

That's quite satisfying.

Wasn't hard enough... I then have to hope...

Deep joy.

That they'll work.

There's some moisture on my spectacles

because I started weeping.

Welcome to virtual reality 1970s spec.

This is a 1971 Triang Hornby Flying Scotsman train set;

the perfect miniature railway.

And it was absolutely brilliant because you just plugged the track together,

wired up the transformer, plonked the locomotive

and the coaches on the track and off it went.

But not here, because it's been dismantled

into its 138 component parts.

And this is my Flying Scotsman with realistic chuffing sound train set,

which I have owned for over 40 years.

Now as this train set is powered by electricity

or as it was still known in the seventies, the miracle of electricity,

I thought we'd start with the electric motor,

which is these components here and what would be really handy

is if we had something like a little plastic tub

to put bits in whilst I walk to the bench.

Something like that.

So there we go that's the frame of the motor,

that is the, armature and the rotor,

bolt or screw, we'll come onto that discussion in a minute,

to hold it together, back plate and magnet.

What we have here is actually one of the most numerously produced

miniature electric motors in history,

this series of motors is known as the XO series

and it's a rather elegant thing, this is the frame,

this is the rotor with the armature on it and the commutator,

we'll come on to all that in excruciating detail in a minute.

It's quite delicate, there's a few things you need to be careful of.

Notably there's windings on each part of the armature there

and the very end of the tiny copper wire is soldered on the commutator.

The purpose of the frame apart from holding the whole thing together

is that it allows the magnetic field of the magnet,

which we're gonna put in in a minute,

to move down the motor and surround the coils.

This is all based on EMF; electromotive force,

which is what makes the motor work.

And the commutator is there to renew the current to it

each time it moves through one segment.

There you go. The first train set I got

for Christmas was when I was very small, so it must've been about 1968,

it was actually second hand because we were poor but we were happy.

Uh, and the train set was actually from the 50s.

And this one came later. This is a much more advanced train set.

But by modern standards it's very, very simple.

But rather, rather gloriously simple in my view

because the thing about Triang trains from which this set stemmed,

again we'll come onto the naming of the company a bit later on.

But the thing is the reason so many of us had the Triang

and later Triang Hornby and Hornby Railways train sets

was because they were fantastically good value.

That is one of the reasons they triumphed, the other was that they were absolutely brilliant.

And although this is very crude by modern standards,

it's still a rather gorgeous piece of miniature engineering.

The commutator relies on being very clean

and it is fairly clean on this one but we can clean it a bit more with a,

a brilliant thing I've got here.

This is a fiber glass pencil,

they're used by people who muck about with small electrical things,

it's very good as a means of polishing things up very very fine,

so you can use it on copper contacts and so on

and you can use it on the commutator of the motor.

Again being very careful not to catch the little copper bits.

Clean, bright and tidy is the maxim of old electrical engineers,

most of them are dead now so don't worry about it.

And you see the fiber bristles polish that copper up

quite nicely, that makes a huge difference.

Well I've actually mended a lot of these trains

'cause the tragedy of these is that

a lot of people sort of my age and a bit younger have these in the loft

and have dug them out thinking ah, my children

will play with these like I did when I was a boy.

And of course when they're shown them they look up from Pokémon Go for half a second

and go, "Yes Dad, that's fascinating."

Uh, but then of course Dad wants to play with them.

But the trouble is after they've been in the loft for 20 or 30 years

they don't work because they have congealed oil on them

and so on and contacts have come apart, you know dry joints and so on.

They're quite easy to restore and I've done quite a few for other people.

It's 'cause I haven't got any proper friends.

I think we'll put the magnet in next.

I'm going to show you something really brilliant that somebody gave me,

it is... a re-magnetizing device,

no it isn't, that's err a polishing gonna kit from the man who owns this workshop.

Who's moved my magnetizing?

So that is a small magnet re-magnetizer.

Magnets are weird things really because in some ways

magnetism is similar to electricity but in other ways it isn't,

for example you can't really insulate magnetism,

that was one of those very smug things that

physic teachers used to say in the olden days.

And study of magnets goes back to,

well the scientific revolution and before that.

A bloke called Gilbert wrote a Latin treaties de-magnet if I remember rightly.

And in early days as part of the mechanical philosophy

I think it was thought that magnetism was actually a flow of particles.

Quite literally that knocked things into alignment or out of alignment.

We know understand it slightly differently from that.

But the important piece of kit in this box is a compass.

Because magnets have a north and a south pole

and you have to get the magnet the right way round in the mounts.

And not that that makes any different to it running

it will run whichever way round magnet is.

But if you don't all your magnets in all trains

around the same way when you select forward on control box,

some trains go forwards and some will backwards.

So the convention is north goes to the top.

So that end, which attracts the red end,

is the north pole of the magnet. And I can tell you,

just with a simple screwdriver test, that that magnet is pretty weak,

so we'll re-magnetize it.

So this device is marked on this side, north goes that way,

so you put that between the two bars, the two pole pieces.

You know it's thought that sharks are repelled by magnets

so if you always go swimming in the Bahamas with a train set you'll be fine.

Here we go, ready? It's very exciting.

That's it. However, I bet you...

But I can already feel that that's much stronger than it was,

and to do our little screwdriver test, if I put that there,

take the same screwdriver I can now, there you go look, I can pick up,

that's how much better magnet is and that will the motor more powerful

and less prone to overheat, because it will actually draw current that way.

Now to hold that in place is this.

That begs a fascinating question that you can take down to the pub with you later:

is that a screw or is it a bolt?

Now one definition says that a bolt is not threaded all the way up

as indeed this one isn't, it has a plain shank,

because its main function is as a dowel to line things up which this does,

because it passes through the hole in the magnet and keeps it all in alignment.

A bolt is secured by a nut, which we also have here.

So technically that, I think, is a bolt.

The definition of a screw, or one definition of a screw

is that it passes through a component and screws into another component,

so say the screw that goes through the engine case on a chainsaw

and then screws into the body of it, that's a screw.

Another definition says that it's a screw if it's threaded

all the way along its length and a bolt if part of it is not threaded.

Another definition says that if it's small it's a screw because a bolt can't be small

but I think technically that's a bolt.

Right the 8BA spanner...

It's a very old British standard, goes on that end and we have to put the,

what's called a hairpin spring, which is going to hold the brushes,

I'll explain all this in a minute.

And I mean I can hear you screaming please don't but I'm going to anyway.

It's a nicely designed little screw/bolt

because it another shoulder on it that means this,

this spring remains free even though it's in place.

And you can now feel, you can't feel because you're watching the television,

but I can feel that now the magnet is in place and re-magnetized.

instead of that spinning freely, it now moves in a series of little clunks,

because there's a magnetic field in there, that's fab isn't it?

This is isopropyl alcohol.

It's the stuff that goes on those swabs

that they put on your arm before they give you injection.

Sometimes known rubbing alcohol. I think this might be what surgical spirit as well.

That's a very old fashioned term that my grandmother used to use.

It evaporates very quickly. If you buy it as surgical swabs they cost about a pound each.

If you buy it in a tin like that it costs about 4 quid

for more than you'll ever use in your life time.

This is a great workshop moment. If you do this you have a cup of tea

and a glass of turps or meth's or isopropyl alcohol and you're talking,

at some point you will drink... the cleaner and not the tea.

So let's have a convention that says that goes there and the cup of tea goes there.

Um...

The brushes are made of copper,

they have blobs of carbon on the end

to transfer electricity to the commutator.

These are quite grubby. I'm gonna use the fiber pencil again

and dip it in the alcohol which is a thorough but benign cleaner

it won't damage anything.

You see? Filth, the enemy of electricity,

whatever electricity is, nobody really knows of course.

That goes through there.

And I've gotta put the other one in.

I can barely see it myself, I'm so blind these days, there you go.

Now, the interesting thing actually about

a toy train from this era, we're talking about the early 1970s,

it is exactly at that time that the video game started to emerge,

things like the very first Ataris.

In fact at home we had the, the very early TV tennis game