TOOLS AND TECHNIQUES - MAKING HOLES IN PLASTIC Flashcards
What sizes do twist drills come in?
A range of sizes from the thickness of human hair to 100mm in diameter.
Those used by schools usually range from 1mm to 13mm in diameter.
What are twist drills made of?
High speed steel (HSS)
What can plastics be drilled with?
A hand drill or a pillar drill
What are pillar drills sometimes referred to and why?
A sensitive drill because you can ‘feel’ the drill cutting into the work as the feed handle is turned
Why should you never attempt to drill close to an edge on plastic, especially acrylics?
The drill exerts a sideways pressure on the material and may cause cracking.
How do you drill a hole using the hand drill?
- Clamp the work firmly to a bench surface with waste material underneath (small work may also be held in a machine vice clamps to the bench)
- Locate the drill tip in the small indent made during marking out and apply gentle downward pressure on the drill while turning the handle
Why should you take special care when a drill exits through acrylic sheets?
Because acrylic sheets are brittle and may crack.
How do you drill a hole using a pillar drill?
- Check the drill speed with your teacher - small drills need a fast speed and large drills need a slow speed
- Fix the drill into the chuck and remove the chuck key
- Ensure the work is held securely in the machine (clamped to the drill table) - work should be firmly resting on waste material
- Lower the drilling machine guard and PUT ON GOGGLES
- Turn the machine on and lower the drill gently
Why should you your work rest on waste material when using a pillar drill? 2 points
- It protects the drilling equipment
2. It reduces the possibility of cracking when the drill breaks through
Why should you raise and lower the pillar drill several times?
To get rid of dwarf which may weld itself into the flutes.
Using a lubricant will help avoid this.
How do you cut larger diameter holes in plastic?
By using a hole saw cutter running at a very low speed. The same steps when using a pillar drill should be used and special care should be taken to clamp your work.
What would you use to cut large holes with a saw in plastics?
Large diameter holes, including square and rectangular ones, can be cut out using a ABRAFILE or COPING SAW
How would you use an abrafile or coping saw to cut large diameter holes in plastic?
- Mark out your hole with a compass and drill a small hole anywhere on the line so that the saw blade can be passed through
- Re-assemble the saw and, as you cut, gradually turn your work around in the vice. Remember to keep the actual cut close to the vice jaws.
What are CONECUT SHEET & TUBE DRILLS?
CONECUT tools drill clean quick holes in steel up to 2mm thick and in non-ferrous metals, plastics, Formica and plywood.
A range of sizes can be drilled with one tool - the further the tool advances the bigger the hole.
What are step drills?
Each tool cuts parallel holes in a range of specific hole sizes.
For use on sheet metal or plastic to stated minimum thickness.
