Learning objective of the project.
By designing and making a phone holder KS3 students will be introduced to Engineering tools and machinery. Students will apply knowledge and understanding to work independently with equipment such as the metal lathe, pillar drill, measuring & marking tools, and how add a surface finish to steel. By the end of the project students should be able to assess and conclude if they would like to continue their studies of Engineering to GCSE level.
Please see the attached files for work booklets, work sheets and end of module test
If you have any questions please add them to the comments section at the end.....Jonny :)
Step 1: Designing
The students can use a selection of sources for inspiration e.g. flowers, architecture, nature, patterns, coral reef, etc... Using the design inspiration page, they start by sticking in the chosen image then focusing on part of it, then sketch the basic lines that make up that image. By using the phrase “Rearrange, Repeat, Rotate” create a design idea as per the example shown then repeat the process to create a range of ideas.
Step 2: Card Model + Design Development
Now make a card model of their favourite idea, the students can peer assess each others work on the following criteria; Stability, Strength, Aesthetics, Manufacture (ability to make the design). The model is disassembled and stuck onto the model and development page then annotated with info on the discussions they just had. The teacher needs to sketch exploded views of how the rods join to the sides.
Step 3: Aluminium Sides: Marking Out
Tools; Scriber / layout fluid
Remember H&S is super important in the school workshop, please ensure your students are adequately briefed on tools, machinery and workshop behaviour. The first step is to mark out one of the aluminium sides with the design, you can use layout fluid, if not use a permanent marker to colour the aluminium, this is done to make the lines easier to see. Use a scriber to scratch the lines onto the work piece.
Step 4: Aluminium Sides: Cutting Out
Put the two aluminium sides together so they are cut at the same time (saves time and makes them identical). Cut the aluminium using the hacksaws I would recommend using ‘soft jaws’ in the vice to avoid marks appearing on the aluminium. Remember to tell the kiddies to cut in a straight line downwards and to rotate their work in the vice.
Step 5: Aluminium Sides: Filing & Sanding
Keeping the two sides together use flat, half round and needle files to smooth all the edges. Then use abrasive paper to smooth the edges further. The sides also need sanding until all file marks are removed.
Step 6: Aluminium Sides: Marking Out Holes
Use a scriber to mark out the two holes for the bolts to hold the steel rods in place, they must not be too close to the edge and you need one rod at low front and the other at high back. Centre punch the marks to be drilled.
Step 7: Aluminium Sides: Drilling Holes
Keep the two sides together and use a hand vice to safely hold the work piece whilst drilling at Ø5mm (remember goggles on, hair tied, sleeves rolled). If there are burrs on the underside of the work piece, use a Ø10mm drill bit to remove them by hand.
Step 8: Aluminium Sides: Sanding
To finish the sides use abrasive paper to create a ‘brushed’ look. For best results ensure you sand in one direction.
Step 9: Steel Rods: Cutting To Size + Facing Off
Tools; Hack Saw / Steel Rule / Scriber
Measure and mark out the steel rods using the steel rule and scriber (they need two rods of equal length). The length of the rods = width of phone / Ipod + 10mm. Using a hacksaw the students need to cut two rods to the correct size. Use the lathe to face off all four ends ensuring the two rods are the same length. Remember H&S rules for machines!
Step 10: Steel Rods: Centre Drilling
Centre drill all four ends to a depth of roughly 5mm.
Step 11: Steel Rods: Drilling The Holes
The Ø4.5mm x 20mm deep hole needs to be drilled in all four ends, go slow with plenty of oil.....if not....lots of snapped drill bits!
Step 12: Steel Rods: Threading Holes
Thread the holes at M5 make it very clear to the students that they must oil the tap and not use too much force or the tap will break, especially when it hits the bottom of the hole.
Step 13: Steel Rods: Sanding
Sand the rods ready for oil blacking, You must ensure they are totally clean of corrosion or oil.
Step 14: Steel Rods: Oil Blacking
Machines: Brazing Hearth / Extraction
Put the rods on something like a welding rod. Heat the rods one at a time until the steel is ‘just before red’ if the rod is over heated let it loose its red glow then drop it in the oil. As you can see from the images when dropped the oil will smoke, you must have a suitable extraction system to remove fumes. When removing the rods from the oil they will still be very hot! Once cooled and clean if the oil black finish is patchy you can re-sand and re-black. I have a mesh ladle that sits at the bottom of the oil pot. Ensure full heat safety gear is worn and one to one adult supervision is available, if the oil does ignite and does not self extinguish immediately, put the lid on the container......DO NOT ADD WATER! Full extraction must be used.
Step 15: Acrylic Sides: Marking + Cutting Out
Tools; Coping saw
Using a biro draw design onto protective film that comes with acrylic (if film is removed masking tape can be used to recover the acrylic surface). Just like the aluminium cut both sides at the same time use a coping saw. (note remind the students their designs must be ‘chunky’ or the acrylic will snap’)
Step 16: Acrylic Sides: Filing & Sanding
Using flat, half round and needle files smooth out the shape then use abrasive paper to finish the edges, wet & dry paper can be used as a final stage to polish the edge.
Step 17: Acrylic Sides: Marking & Drilling Holes
Machines: Pillar Drill
Put the acrylic next to the assembled aluminium structure to mark where the hole needs to go.
With both pieces of acrylic put together use a hand vice to hold whist drilling at Ø5mm. NOTE the hole must not be too close to the edge, the hole must be drilled slowly and bizarrely wood drill bits seem to help prevent breakages!
Step 18: Assemble :)
Tools: Allen (hex) Key
Assemble the components together.
I have also included some pictures of my students work.
Solutions to problems
Bolts don’t fit into threads: Sometimes the start of the thread gets damages, just de burr the hole with a large diameter drill bit and run the tap back through.
Bolts are too long to fit into the hole: Cut bolts shorter with a hacksaw then file the cut edge to remove rough edge.
No Lathes: You can file the ends flat, centre punch the middle of the rod, secure in the V of a drill vice then drill at Ø4.5mm x 20mm deep. Follow instructable to create a thread in the hole.
Acrylic breaks: Design is too thin / drilling too quick / hole is too close to the edge.
Oil black is patchy: surface not clean before blacking / not hot enough