Lesson video

Hello, my name's Mrs. Fletcher and I'm here to help you with your design and technology lesson today.

This lesson is called Make an Accurate Box Frame and it's part of the Cams automata unit.

It's a practical lesson where we get to build a wooden box frame that can be used to house a cam mechanism or to make an automaton toy.

So let's have a look at what we'll be learning about today.

The outcome of today's lesson is I can make an accurate box frame, so that is because it's such a practical lesson, by the end of the lesson we will have made a box frame and it will be accurate.

That means all of the pieces will fit together nicely because we have been very precise with our measurements.

There are some key words we're going to need in today's lesson.

Let's have a look at those today.

We have the word measure, which means to determine the size of an object using a measuring tool.

We've got the word join, which means to link or connect two or more things together.

And we've got the word strengthen, which means to make stronger.

So those are the words.

We might see them come up in the lesson.

Let's have a look at what we're going to be doing in this lesson today.

So today's lesson is split into three parts.

First of all, we're going to look at some accurate sawing techniques, so that's how we can saw accurately.

So that's precisely, we're going to then look at joining some wood sections and how we can do that.

So that's an important part of building a box frame and we'll be looking at how we do that in that section of the lesson.

And then finally we'll be looking at strengthening a box frame.

So once it's built, we want to make sure it's strong ready for use.

So that will be in that part of the lesson.

So let's get started with looking at some accurate sawing techniques that we can use.

It is important to be accurate when sawing and joining wood pieces together.

But why, well let's have a look at this table.

What's wrong with it? Have a think.

Pause the video if you need to.

What's wrong with the table? So what did you think? Well, precisely the legs are not the same length, which means the top is not level.

It's not really much use as a table.

So that tells us why accuracy is important because ensuring all the legs on that table are measured to the same size and cut exactly to the same length would make the top of that table level, which is what we want it to be.

If we don't make them accurate, then we get the problem we can see there where the top of the table is not level.

When using a measuring tool, we need to remember a few things.

So we need to make sure we remember we start measuring at the zero, so not at the very end of the ruler or the tape, but at the place where the zero is marked on the ruler.

This is to make sure we can read the accurate length.

So here we can see where our object lines up on the integers of this ruler.

We can accurately read that it's 118 millimetres.

So we can only do that if we line the ruler up correctly.

Sofia's reminding us there that to make sure to double check the measurements before making any permanent changes.

So we wouldn't want to cut a piece of wood before we've double checked that we've measured it properly because we can't go back and change it.

This line measures 12.

7 centimetres, but how many millimetres is that? If I was to convert it from centimetres to millimetres, how many millimetres is that? Is it A, 123 millimetres? Is it B, 125 millimetres or is it C, 127 millimetres? Pause the video, have a think.

So what did you think, well done if you said it was 127 millimetres.

So Jacob and Sofia are getting ready to measure and cut some wood.

To stay safe, they need to remember a few things.

They need to remember to tie back any loose hair.

They need to remember to roll up their sleeves.

They need to remember to clear the table so they've got a tidy working environment and they need to make sure they've got all the tools that they need for this task in front of them ready to go.

They might also want to wear goggles and an apron as well.

We need these to following tools and equipment in order to measure and saw wood accurately.

We'll need a ruler, we'll need a junior hack saw, which we can see there is a saw that has a solid frame and handle to hold that blade in place.

And then we need a bench hook, which is used to hold wood in position on a table.

Quick task there before we start, we've just had a look at that hacksaw, but can you label the parts that you have just seen? Which part is A, which part is B and which part is C? Pause video, have a go.

Okay, how did you get on? Let's have a look if you got the answer correct, we should have A is the frame, B is the handle and C was the blade.

Well done if you've got all those in the correct place.

So let's go over those steps for sawing wood safely and accurately.

So first of all, we need to measure the wood that we're going to cut.

Then we need to mark out the place where we're going to make the cut.

We might want to double check that to make sure we've definitely got the right measurements.

Then we want to position that bench hook on the table ready to secure the wood, and you will need to secure that bench hook with a clamp as well.

We need to position the wood in the right place.

So holding it correctly with your hand and your thumb being the thing that holds the wood in place, you need to make an indentation.

So that's by drawing the saw back three times in the same position to make an indentation.

And then you want to begin sawing with those full, even strokes until you've sawn through that piece of wood.

Quick check before you start though, which hand should you use to hold that piece of wood? Is it your writing hand, your non-writing hand or your left hand? Which hand should you use to hold the piece of wood? Think about which hand you'll be using to saw.

Which hand will be holding the wood? Pause the video, have a think.

Okay, welcome back, what did you think? Which hand will be holding the wood? It's your non-writing hand.

So you'll be using your writing hand.

So if you're right-handed for writing, you'll be using that hand for sawing.

If you're left-handed for writing, you'll be using that hand for sawing.

So the opposite hand, your non-writing hand, will be used for holding that wood in place.

Okay, time for the first part of your task then.

So first of all, I want you to measure and mark four sections of wood from the piece of square section wood that you're using in today's lesson.

I want you to mark out four sections that are 100 millimetres long.

They need to all be the same size.

So you need to measure and double check your measurements to make sure you've got four pieces that were are 100 millimetres long.

We're just going to mark them out on the piece of wood.

If you've got one long piece of wood, they might all fit on one piece.

If you've got smaller pieces of wood, you might need to mark them out on separate pieces of wood.

But the important thing is, as Sofia's reminding us there, is that you double check those measurements so that each piece is 100 millimetres long.

When you've done that and marked out the pieces, come back and we'll move on to the next part of the task.

Okay, how did you get on? Hopefully you were able to mark out and measure those four sections really accurately.

So you should have marks that show where you can cut to make four separate sections that will each be 100 millimetres long.

So that leads us into the second part of the task.

Now we've marked them out, we need to cut them.

So using those steps to so accurately, I want you to cut the four sections of wood that you measured out.

So by the time you've cut them, you should have four equal pieces, four pieces that each measure 100 millimetres.

You might have some spare wood, some excess that you can tidy away.

They won't need those pieces.

You just need the four identical pieces of wood that measure 100 millimetres.

Pause the video, come back when you've done that step.

Okay, welcome back.

Hopefully you managed to follow all those steps, recapping if you needed to, to accurately saw through your wood section to make four equal pieces that each measure 100 millimetres, you can always recheck now that you've cut them to make sure that you have those four pieces ready for the next part of the lesson.

Okay, so the next part of the lesson is where we look at joining those wood sections and there's different methods for this.

So we're going to have a look at which method we're gonna use today.

Wood can be joined without using screws or nails.

So screws and nails are one method we could use for joining wood, but we don't need to use those necessarily.

It can be shaped to interlock like in that first image there or it can be glued.

So they usually provide, these two methods usually provide a much neater finish than screwing in screws or hammering in nails.

Wood that has been joined with glue can sometimes need some extra support though to stop it from coming apart.

Cardboard triangles can provide this support and when we use cardboard triangles to provide support for a joint, we call that triangulation.

So you can see here a folded triangle support has been placed in the corner joint where the wood is joined together and that provides some extra strength to that joint to keep it securely together.

Quick check then before we move on, using triangles to strengthen a wood joint like we've just seen, is known what, is it A, glueing , B, interlocking or C triangulation.

What is it known as? Pause the video, come back when you've had a go.

Okay, what did you think, well done if you said it's triangulation, the clue is in the name there.

We use a cardboard triangle.

It's called triangulation.

Well done if you got that right.

We can join and strengthen a frame using these tools and materials.

So we'll need some thick card, we'll need some thin cardboard strips.

For the triangles, we'll need an A4 piece of card cut in half length ways.

We'll need two prebuilt frames ready to use in this task.

We'll need some scissors.

We'll need the four pieces of wood that we cut earlier in the lesson, the 100 millimetre piece sections, and we'll need some PVA glue and a spreader.

So let's have a look at the steps to join the frame and to strengthen that corner joint.

So first of all, you need one of the rectangular frames that we needed for this task and the four upright sections that you cut earlier on.

And first of all, you're going to glue those four upright sections, one to each corner of that rectangular frame.

So have a look at the image on the screen for the position that you need to glue them into.

Now you need to wait for the glue to dry before you move on to step two.

In step two, we want to use that piece of thin card that we set aside for the card triangles.

And I want you to cut out four triangles and trying to make them symmetrical triangles.

That means they're equal on each side if we fold them in half.

And that will make a much stronger joint because it'll have the same amount of support on each side.

I want you to fold them in half and then glue them wrapped around each of those corner joints that you've just created by glueing those uprights to the rectangular frame.

So have a look at the diagram there.

You can see they wraps around the corner of those now three pieces of wood that join together.

And then for step three, I want you to repeat that with the top section.

So you're gonna get the second rectangular frame, glue that to the top of those four upright sections that we glued in at the start.

And then again, cut, fold and glue four more supporting triangles to the four corners of that top section.

So if you look at the diagram in the third step, we've got the two rectangular frames with those four uprights in between them and those cardboard supports supports wrapping round each corner of the frame.

So you should have eight supports in total.

Sofia's reminding you that you need to take your time with this task.

It can be very tricky, can be a bit fiddly to apply those triangles in the right place.

A top to tip is to make sure that the upright sections are dry before you start applying the next stage, just so that they don't fall out of place because they're not secured yet.

So a quick check before you get on with your task.

How many corner sections will the box frame have? Will it be four, will it be six or will it be eight? Pause the video, have a think.

Okay, what did you think? Well done if you said it is eight.

So if we had four triangles in the corner sections at the bottom and four at the corner sections on the top, then we'll have eight all together.

Okay, so your task then is to follow those steps that we've just run through to join and strengthen those two rectangular frames using the sections of wood that you cut earlier.

So we've got there in the image the two rectangular sections and the four upright sections that will join together.

And they will be supported and strengthened by those eight cardboard triangular sections.

So we're using triangulation to strengthen those joints where we've glued the wood together.

So the joint is where you have glued it together, pause the video and come back when you've completed that tricky task.

Okay, welcome back, how did you get on? Well, you should now have a box frame that looks a little bit like this, that is strengthened with those card triangles.

Hopefully you need to leave it to dry before we move on to the next stage so that it is strong and ready to use.

So let's have a look at the next section of our lesson.

So we're going to move on to the last part of our lesson now, that third part of the lesson where we get to look at how we strengthen the box frame as a whole.

So we've looked at joining those wood sections and strengthening those joints.

Now we're going to look at strengthening the box frame as a whole.

So triangle supports can strengthen joints and a box frame can be strengthened further by adding rectangular panels.

This is particularly important if other elements such as an axle are going to be joined to the frame later on.

So we need to add that strength if we are going to add other components to our box frame.

A length of card can be measured and folded to wrap around two sides of the box frame.

So here we can see the rectangular piece of card.

So this is where we will need those.

The A4 card that's been cut in half length ways, you're going to cut and measure that to fit your box frame.

So it's going to cover the top and one side.

And then another piece is gonna cover the bottom and the opposite side.

So you need to measure both of those sides to get the accurate measurements for your box frame.

So I measured my box frame and I measured that it was 270 millimetres across the top and down one side and it was 120 millimetres wide or deep.

So that's the length that I needed to cut my piece of card.

I then measured where I should fold it so that it could wrap around both of those sides.

So I measured, my top panel was 150 millimetres, so that's where I needed to do the fold.

So the second part can fold onto the side of my box frame.

You need to measure yours as I say separately because everybody's box would be slightly different.

We need to get an accurate measurement for your individual box.

That's what it should look like if we put it next to our box frame, it should be the same length as the top and one side of your box frame.

Then we were going to repeat that with the second piece of card so that it fits across the bottom and the opposite side.

So we've got a piece of card that wraps around the whole structure of our box frame and that's how it will strengthen the whole of the structure by wrapping around it completely.

Quick chat before you get to have a go on your box frame, what shape are those card panels going to be that you cut out for this task? Will they be A, triangle, B rectangle, or C, a square? Pause video, have a think.

Of course, they are a rectangular shape.

To be able to envelop the top and side, they need to be a rectangular shape.

Okay, so that's your task then is to measure the length of two sides of your box frame, one of the long sides, one of the short sides, add them together so you've got the total length and then measure the depth.

So that's how wide the piece of card is going to be.

Once you've done that, draw two rectangles onto those pieces of card with those exact measurements and cut out both of those shapes.

Mark the length of the top of your box on each card so that that's the point where you're going to fold the card so that it can wrap around both sides.

Making sure you accurately measure is the key to making this task this part of the task successful.

So make sure you measure and measure again if you need to, pause the video, come back when you have two rectangles that fit snugly round your box frame.

Okay, welcome back.

So you should have those two rectangles now with the fold measured in the correct place so that we know it fits around two sides.

Each piece fits around two sides of your box frame.

So two accurately measured rectangles with a fold in the correct place.

So what we're going to do with those two pieces then? Well you're going to carefully spread glue onto the outer surfaces of the two measured sides, so the top and side that you measured to start with, you're going to put some glue on there and you're going to attach the card rectangle, making sure that everything's aligned correctly.

So it all lines up with the edge of the box frame, if you need to make some alterations, then make them before you stick it down so that it fits perfectly.

So you can see here on the diagram the places where I've applied the glue is where the cardboard rectangle is going to sit.

And you're going to repeat that, turn your box upside down and repeat that on the opposite side so you can attach your second rectangle in exactly the same way.

So by the time you finish, you should have a completely wrapped box frame, pause the video and come back when you've done.

Welcome back, so hopefully you managed to do that task and you managed to make two accurately measured and cut rectangles that you could apply to your box frame.

And you now have a solid box frame that has been strengthened with cardboard rectangles.

So we're nearly at the end of the lesson now.

Again, we've had fun with this practical lesson showing us how to strengthen joints and strengthen a box frame.

What have we learnt along the way? So measuring accurately is essential to creating an effective product.

So if we think back to that table at the start of the lesson, it wasn't an effective product.

It didn't work well because those legs had not been measured and cut accurately.

So measuring is the first step to making an effective product.

But equally as important is the sawing technique that we use.

If we don't saw accurately on those measurements that we've already made, then those measurements won't stay accurate.

So we need to be as accurate with our sawing as we are with our measuring.

Joining with a selection of techniques will strengthen the box frame.

So we saw that using those card triangles, using triangulation is a method of strengthening a corner joint, particularly where we've joined separate pieces of wood together.

And those card side panels that we use to wrap around the whole of the box frame will strengthen that box frame for use with other components so we can add to that box frame now knowing that it's strong enough to take those components.

That's the end of the lesson then.

I've had fun making my box frame and strengthen it.

Hopefully you have too and I'll see you again in another lesson.

Goodbye for now.