It will be my next project for my after school engineering club. Check the vid to see the key rings in action!
By following a detailed set of instructions and videos from the Instructables website, yr9 students (13 year olds) will make a glow-in-the-dark key ring. The students will recall previously learnt skills on the metal lathe, e.g. facing off, centre drilling, and drilling to a given depth. This project will introduce the students to a milling machine and an indexable head. The project teaches how to use these precision tools to a high degree of accuracy and the students must aim to work within a tolerance of +/- 0.1mm. To achieve this tolerance the students will have to use basic mathematical calculations of linear measurements and angular divisions.
Step 3: Tapping the thread
- Put a M8 tap into the chuck and manually tap the thread. Do not turn the lathe on!
- Once its started remove from the lathe and complete the rest in a metal vice.
Step 4: Y axis (centre)
- Remove the work piece from the lathe and secure in the indexing head.
- Put in the centring bar (this can be any rod with a known diameter)
- Slowly advance the rod towards the work piece, using a thin piece of tissue as an indicator......keep moving the tissue, when the rod grips the tissue you know its exactly on the edge of the work piece.
- Lower the machine bed and zero the Y axis dial.
- Use the following calculation (Ø of centre rod + Ø of work piece / 2)
- 8mm + 9mm = 17mm 17mm / 2 = 8.5mm
- Move the Y axis dial 8.5mm
- If done correctly you should be within +/- 0.1mm of the centre