Hello and welcome to today's design and technology lesson.

My name is Mrs. Fletcher, and I'm really happy to be able to help and guide you through your learning today.

Today's lesson is called "Wood Construction and Joining Techniques," and it's part of the Cams: Automata unit.

In this lesson, we'll get to learn how to measure, saw, and strengthen wood.

So let's have a look at how we'll be learning that today.

The outcome of today's lesson is "I can saw and join wood," so we'll be learning how to do those accurately and safely.

Let's have a look at the key words that we're going to need to use in today's lesson.

We're going to see these come up in today's lesson, so let's have a look at what they mean.

So first of all, we've got the word "technique." The word "technique" refers to a specific way of completing a task.

So we're going to be learning some techniques today.

Then we have the word "accurate," and that means to be correct and precise, and we particularly use that when we're talking about measurements.

Then we have the word "joint," which is used to describe the place where two materials are joined together.

And then we have the word "triangulation," which is where we use triangles to strengthen structures, particularly the joints on structures.

The lesson is split into three parts today.

So first of all, we're going to be looking at measuring for accuracy and how we do that effectively.

Then we're going to move on to looking at some safe sawing techniques, so how we can saw wood carefully and safely.

And then we're going to look at strengthening corner joints and how that works and why we do it.

So let's get started with that first part: measuring for accuracy.

Several products are made from wood: instruments, furniture, toys.

Each product must be carefully constructed in order to look good and to function properly.

When constructing products from wood, it is essential that it's measured and cut accurately.

So if we don't measure and cut things accurately, they're not going to function or appear as they are supposed to.

What would happen, for example, if a door panel was cut larger than the door frame where it was going to go? Have a think.

What do you think? Exactly.

It wouldn't fit.

To measure accurately, we must use the correct tools.

Can you name these tools that are often used to measure the size or the angle of something? Pause the video and have a think.

Okay, did you recognise any of those tools? I'm sure you did, so let's have a look.

We've got a ruler, a tape measure, a protractor, and the set square.

You may have used some of those at school or at home.

Quick check then: which of these products is made from wood? So we're talking about wood today.

Which of these is made from wood? Pause the video, have a think.

Welcome back.

What did you think? Well done.

It's the instrument.

The guitar, of course.

We can see sometimes just by looking at a product what material it's made from.

Sometimes it's a bit trickier, but that one is quite obvious.

It's the guitar is made from wood.

So when using a measuring tool, we need to remember to start measuring with the zero in the correct position.

So we don't start from the end of the ruler or the tape measure.

We have to start from where the zero is indicated on that measuring tool.

We need to accurately read and mark the length of whatever it is that we are measuring using the correct integers or decimals when needed.

So if we look at this ruler measuring this objects, an inaccurate reading of that would be 120 millimetres because it looks like it's pretty close to that measurement.

But if we want it to be accurate, we need to look more carefully at those integers on the ruler.

So we can see, if we look carefully, it's actually 118 millimetres.

And those two millimetres can make a difference when you're measuring parts of a product or measuring for accuracy.

Quick check then: This line measures 13.

5 centimetres, but I want to know what that would be in millimetres.

So if I was to convert 13.

5 centimetres into millimetres, what would that be? Would it be A, 13 millimetres? Would it be B, 135 millimetres? Or would it be C, 130 millimetres? Pause the video and have a think.

Welcome back.

So hopefully you managed to convert that, remembering that there are 10 millimetres in a centimetre, and you worked out that it is, in fact, 135 millimetres.

Well done if you got that right.

Double checking your measurements before making any permanent changes is really important.

So if you're going to cut a piece of wood, for example, you need to make sure you cut it the right size because you may not be able to go back and change that, particularly if you've done it too small.

So that means we need to make sure that we measure, we mark the place where we want to cut, and then we measure again just to double-check that we have the line in the right place.

Okay, time for a quick check for understanding: How many hundred-millimeter sections would I be able to mark out on this length of wood? So you can see this length of wood is 450 millimetres.

If I was measuring and marking 100-millimeter sections, how many would I be able to fit on that piece of wood? Is it 4, 5, or 45? Pause the video and have a think.

Welcome back.

What did you think then? Well done if you said four.

So if I marked out four 100-millimeter sections, that would equal 400 millimetres, and then I only have 50 millimetres left over, so there's not enough room for another section.

That would be what we call the excess.

So well done if you got that right.

So we're going to use the steps for accurate measuring to mark out the following pieces of square section wood.

So this is your task.

You are going to mark out four sections that are 150 millimetres long, and you're going to mark out four sections that are 100 millimetres long.

So you need to make sure that you line up the edge of the wood on the zero of whichever measuring tool you're using, that you mark a line at the correct integer, and you double-check all your measurements.

So by the end of this task, you need to have those four sections of wood that measure 150 millimetres and four sections of wood that measure 100 millimetres marked out on your square section wood.

Pause the video and come back when you've had a go.

Okay, welcome back.

So remember, we were just marking out in this task.

It was to test that we could measure accurately before we go into any cutting techniques.

So you should have some 100-millimeter sections, four of those, and you should have some 150-millimeter sections, four of those as well.

The number of sections on each piece of wood depends on how long the piece of wood is that you started with.

You may have gotten them all on one piece if you had a really long section, but it's more than likely that you needed to measure them out on separate pieces of wood.

So as long as you've got each one of those measured ready for the next task, you're ready to go.

So in this next part of the lesson is where we'll learn about the safe sawing techniques to make sure we don't lose that accuracy that we've done, with the measuring that we've got from the measuring.

When learning to saw wood, there are a few key things that we need to remember: Safety, accuracy, and technique.

Being prepared and using the correct technique, so that's the method that we are using to do the job, ensures that we stay safe.

Accuracy ensures that we have a quality finish on our products or on our work.

So those are key ingredients to doing this task really well.

Jacob and Sofia are getting ready to cut some wood, and to stay safe, they need to remember a few things.

So they need to remember to tie back any loose hair.

They need to remember to roll up their sleeves out of the way.

They need to remember to clear the table so they've got room to work safely.

And they need to gather together all the tools that they'll need before they start.

They could also wear goggles and an apron if they wanted to as well.

These are the tools that you will need to saw wood safely.

So you'll need a junior hacksaw, which is a saw that has a solid frame, a large handle, and a blade.

And you'll need a bench hook.

So this is a device that's used for holding wood safely in place while we saw it.

A hacksaw has very small teeth, so that's what we call those little grooves on the end of the blade, we call them teeth, and they're very, very small, and that's what enables it to cut through the wood when it's pushed forwards and backwards.

Hacksaw should always be carried down by your side when you're moving around in your environment.

You should hold them by the handle, and they should be pointing down to the floor.

This is to keep you and other people around you safe.

Quick check, then: which one of these is the bench hook? Is it A, B, or C? Which one is the bench hook? Pause the video, have a think.

Welcome back.

Well done if you said it was A.

Of course, it's the device that we use to support the wood when we are sawing.

Jacob has positioned his bench hook on the table, getting ready to saw, and he makes sure he secures that with a clamp, and that's to stop it from moving or falling off the table while we are sawing.

A bench hook is a block that sits right on the edge of a table, and it's used to hold wood in place.

So Sofia pushes the wood up against the top of that bench hook.

So that's the position it needs to be in when we come to saw it.

And she uses her non-writing hand to hold it in place, and that's because she'll be using her writing hand, the one she normally uses to write, to hold the saw and to saw the wood.

So the other hand, her non-writing hand, gets the job of holding the wood in place.

So you can see there, if you're left-handed, the marked piece of wood should be on the left of the bench hook.

If you're right-handed, then that marked piece of wood should be on the right, being held with the opposite hand.

And make sure that it's your thumb that is holding that wood in position, so your hand is out of the way.

Jacob's making sure that he holds the saw correctly, as you will need to as well when you come to use the saw.

So you need to make sure you're holding the whole handle with your whole hand, and you're resting your index finger along the top or side of the frame to keep it steady.

So that pointed finger helps with accuracy because it reduces the movement of the saw when you come to saw through the wood.

So first of all, we need to make an indentation in the wood, and this is to mark the place we're going to saw through, and it helps to locate the saw in the right place so that it doesn't move.

To do that, we need to place the hacksaw on top of the pencil mark that you made into your measuring in the measuring task earlier on.

You're going to make sure your fingers are out of the way of the blade before you move it.

You're going to pull back on that hacksaw once, then reset it back in the position where you started, and repeat that three times.

So you're going to pull it back, reset it, pull it back, reset it, pull it back.

So you're not sawing backwards and forwards; you're just doing a backward motion just to leave an indentation in that wood.

And this will help to give the blade a place to sit when you start to saw.

The way your body is positioned is important as well when you're sawing.

So you need to stand with your left foot forward if you're right-handed, or your right foot if you're left-handed.

That's to keep your balance.

You need to use your whole thumb to hold the wood in place, keeping the rest of your fingers out of the way.

You need to position the saw in that cut that we've just made, in those indentations, slightly tipped forward on an angle.

You need to move the saw backward and forward slowly when you start to saw through the wood.

So we don't need to be quick.

You need to use the middle of the blade, so we are using the strongest part of the blade to cut through the wood.

And you need to make sure you keep your fingers away from the blade at all times.

If you relax your grip on the blade, that will help as well because if you're holding it too tight, it will make it, the wood, the blade will get caught in the wood.

So relax your hand.

Don't hold it too tight.

Quick check then: what is used to saw the wood? Is it A, a pencil, B, a hacksaw, C, a bench hook, or D, a clamp? Pause the video and have a think.

Well done if you said it was the hacksaw.

Of course, the junior hacksaw is the tool we are using to saw wood today.

So let's just go over those steps that we need to saw wood safely and accurately.

So first of all, you need to measure the wood like we did in the first task.

You need to mark the wood, to make sure we don't lose that measurement.

You need to clamp your bench hook to the table so it's in position, ready to start.

Position your piece of wood on that bench hook so that it's in the right place, depending on whether you're left or right-handed.

You need to make that indentation by drawing the saw back three times.

And then you need to saw through the wood using the technique we discussed earlier.

Okay, so that leads us to our task then.

So using the steps to cut wood safely that we've just gone through, I want you to cut the sections of wood that you measured and marked in the first task.

So you marked off those four 100-millimeter sections and the four 150-millimeter sections, so now I want you to saw through each one so they are separated.

And Sofia is reminding that you could use sandpaper to smooth off any rough edges once you've finished with the sawing.

So pause the video, come back when you've had a go at that task.

Okay, how did you get on? Hopefully, you managed to follow those steps to safely and accurately saw your wood.

So now you should have four separate sections of wood measuring 100 millimetres, and you should have four separate sections of wood that measure 150 millimetres.

So we are going to need those later on in the lesson.

So tidy up your area and make sure you're ready for the next step.

So the next part of the lesson, the last part of the lesson, is where we learn about strengthening corner joints, and we'll learn about why that's important as well.

Wood can be joined without using screws or nails.

It can be shaped to interlock.

So that means it's shaped in a certain way that fits together a little bit like a jigsaw puzzle, and that, because it's so accurately cut, it stays together without anything else, or it can be glued.

And both of those methods are usually much neater than using screws or nails.

Wood that's been joined using glue can sometimes need extra support.

Cardboard triangles can provide this support on small models, like the type of thing we're going to be making in today's lesson.

And this is known as triangulation when we use that.

Triangle supports are placed where the wood is joined, and that just helps to strengthen the joint between the two pieces.

Flat triangular supports can be glued across a joint.

So you can see here we've got a right-angle triangle piece of card that is supporting the joint of two pieces of wood there.

And folded triangles can be used to wrap around a corner joint on a box frame like that.

So, quick check: What are triangular supports used for? Are they used to cover joints? Are they used to strengthen joints? Are they used to neaten the joints? Pause the video, have a think.

What did you think? Well done if you said it is to strengthen the joints.

So that's what we are learning about in this part of the lesson: strengthening those corner joints.

So we can make and strengthen a frame using these tools and materials.

So we need those four 150-millimeter pieces of wood you cut earlier, the four 100-millimeter pieces of wood that you cut earlier, a cardboard strip to make your card triangles out of, you can use a joiner if you want, if you have them, which is something that can help keep the wood in position.

We need some PVA glue and a spreader, and some scissors.

So the correct glueing technique will ensure that the wood and the cardboard sections connect properly.

So we need to make sure that we don't use too much glue, so we wipe away the excess on the edge of the pot when we get the glue on the spreader.

That we spread the glue in even strokes and that we remove any excess glue.

So we just leave a thin film that covers the whole of the cardboard triangles that we are using.

That way, it'll stay neat and it'll make sure it connects properly.

So let's run through the steps that you will need to follow in order to construct a frame and to strengthen a corner joint.

So first of all, you will need to glue a 100-millimeter section to one of the 150-millimeter sections at a right angle.

So, looking at the picture there, those two pieces of wood need to be a right angle, and you're going to glue one of the card triangles to the corner in the right-angle section of that joint that you have made.

One on each side.

So, you can see in the image, you've got one on each side of that joint.

Once you've done that, you're going to repeat it again so that you end up with two L-shaped section of wood, and you're going to join those two sections together using glue to make a rectangular frame.

So, you're making two separate L-sections, and then you're going to connect those two sections together and join in all of the joints with those card triangles that you've cut from the thin card.

You're going to repeat steps one and two again so that you have two full rectangular frames that you can see in step number three.

So, we need to allow all that glue to dry, and you might need to allow the glue to dry in between steps as well, but definitely once you've constructed those two frames before we move on to the next step.

Quick check before you move on to the task though is how many sections of wood make each rectangular frame? Is it four, six, or eight? Pause the video, have a think.

Okay, well done if you said it was four.

So those two 100-millimeter sections and the two 150-millimeter sections are what will construct or make your construction of a rectangular frame.

So your task then is to follow the steps to make those two rectangular frames using the sections of wood that you cut earlier and strengthen them using card triangles, making sure you position them in the correct place.

So, you should have two rectangular frames made from two 100-millimeter sections and two 150-millimeter sections.

And each frame should have four cardboard triangles on each side.

So, you can see four on the front side there, but there would also be four on the reverse side, and you've got two of those.

Pause the video while you do that task and come back when you're finished.

Okay, well done.

Hopefully, you managed to construct your two rectangular frames and you strengthen them with cards, so you've got something that looks a bit like this.

Remember, they should be strengthened on both sides.

So, you should have a total of 16 card triangles altogether, eight on each rectangular frame.

If you've managed to do that, well done.

You've done a really great job.

So, we're at the end of the lesson now, and hopefully, you've had fun learning how to measure and saw accurately and using those techniques to build those rectangular frames that we strengthened using those triangular supports.

What have we been learning about then in today's lesson? Well, we've learned that measuring accurately is essential in creating an effective product.

If we don't measure accurately, the product won't turn out as we intend it to, which means it might not function as it is intended to.

Sawing techniques need to be conducted safely.

Saws are safe tools to use as long as we follow the correct procedures and use the correct techniques.

And card triangles can be used to strengthen those corner joints, and this is known as triangulation.

So hopefully you remember that word when you come to work on joining wood in the future.

I've had fun today.

Hopefully, you have too, and I hope to see you again in another lesson.

Goodbye for now.