Bench Machines: Scroll Saw and Drill
AdvancedBench machines cut and drill fast and true: the scroll saw follows curves in thin board, the drill press bores neat holes. Learn their parts, safe operating procedures, and how to choose, maintain and dispose of equipment — then designs become products, safely.
- Bench machines use motors for fast, accurate work — and carry higher risks
- A scroll saw's narrow blade cuts curves and interior openings in thin sheet
- A drill press spins bits into clamped work for accurate round holes
文體小知識：科技知識說明文按構造、用途、程序的次序講解機器，配合安全守則，令讀者能正確而安全地操作設備。
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1However fine the drawing, only processing makes it real. In the workshop, bench machines guarantee efficiency and accuracy: the scroll saw's racing narrow blade cuts smooth curves in thin wood and plastic, while the drill press spins its bit into clamped work to drill round holes in exactly the right places. Jobs impossible by hand become easy and reliable.
2But machine power and speed dwarf hand tools, so the safety rules are stricter. Before use: goggles on, hair tied, loose clothing secured, and the equipment checked with the teacher. In use: clamp the work, keep hands away from moving parts, and clear chips only after a full stop, with a brush rather than fingers. Safety procedure is not a cage — it is what lets a machine's power be used with confidence.
3For example, holding a small metal plate by hand under a drill press invites trouble: the instant the bit grabs, the plate whirls with it and can cut the palm. Clamp the plate in the machine vice and the same job is safe and neat. The core principle of machine safety: let fixtures replace hands, let procedures replace memory, and let checklists replace last-minute judgement.
4Equipment management also means choosing, maintaining and disposing: pick machines to suit material and process, replace blunt blades, sharpen bits, clean the body and add lubricant on schedule; register and dispose of worn-out machines by procedure, recycling their metal. Treat the machines well and they will work safely for you — the basic attitude of everyone who builds things.
1Summary 重點摘要
Bench machines cut and drill fast and true: the scroll saw follows curves in thin board, the drill press bores neat holes. Learn their parts, safe operating procedures, and how to choose, maintain and dispose of equipment — then designs become products, safely.
2Vocabulary cards Vocabulary
Processing equipment fixed to a bench and driven by a motor.
A machine whose narrow blade races up and down to cut curves.
A bench machine that spins a bit and feeds it by handle to drill holes.
The narrow toothed strip on a scroll saw that does the cutting.
The rotating cutting tool on a drill press that bores round holes.
The part that grips the drill bit and spins with the spindle.
The material being worked on.
A clamp fitted to the machine table that grips the workpiece.
Routine care that keeps equipment sound, such as changing tools and cleaning.
Handling unusable equipment by procedure, recycling materials where possible.
3Step by step Steps
- From hand tools to bench machinesHand tools rely on muscle: fine for straight cuts, slow and tiring for thick stock, curves or repeated identical jobs. Bench machines stand fixed on the workbench, powered by an electric motor, cutting and drilling quickly and accurately — the workhorses of the workshop. But their power and speed far exceed hand tools, and mistakes carry heavier consequences, so the first lesson of every machine is safety. For example, a scroll saw cuts a curve in eighteen-millimetre plywood in minutes with a clean edge; by hand with a bow saw, the same board takes half an hour and leaves a ragged line.
- Scroll saw: parts and usesA scroll saw cuts with a fine, narrow blade moving rapidly up and down, ideal for curves and interior cut-outs in thin wood and plastic. Its main parts are the table, blade, upper and lower guide assemblies and the tensioning device: the table supports the work and tilts for angled cuts; the guides steady the blade so the cut stays true; the tensioner keeps the blade taut so it does not wander. For example, to cut a pierced pattern in a lamp-box panel, drill a small hole at the centre, thread the blade through, and follow the line slowly — shapes hand tools could never manage.
- Operating the scroll saw safelyBefore switching on, confirm goggles are on, hair tied back, loose clothing secured, and ask the teacher to check the blade's fitting and tension. Lay the work flat on the table, keep both hands at the sides of the blade rather than in front, feed slowly and steadily, and slow down at corners. Never bring hands near a moving blade, and clear offcuts only when the blade has fully stopped. For example, forcing a sharp turn twists and can snap the blade; the proper method is to cut a few relief cuts before tight curves, keeping the line smooth and the blade lasting longer.
- Drill press: parts and usesA drill press spins a bit at high speed while the feed handle presses it into work clamped on the table, drilling round holes of accurate diameter with square shoulders in wood, plastic and metal. Main parts: base, column, table, spindle, chuck and feed handles; the table adjusts in height and angle. Choose bits to suit material and hole size — metal needs high-speed-steel bits and cutting fluid to keep them cool. For example, drilling dowel-position holes in a storage box's side panels, the drill press puts every hole in the same place, so the box assembles square and true.
- Operating the drill press safelyThe drill press's greatest dangers are the spinning bit and an unclamped workpiece. Clamp the work in the machine vice or fixtures — never hold small pieces by hand; lock the bit in the chuck and remove the chuck key at once; choose the speed for the material and ease off pressure as the bit breaks through, so the work is not grabbed and spun. Long hair, gloves and loose sleeves must stay clear of rotation. For example, a small metal plate held by hand can be snatched by the bit and whip round, cutting the palm; clamped, the same job is safe and accurate.
- Choosing, maintaining and disposing of equipmentChoose equipment by material, process and accuracy: straight cuts to the hand saw or bench saw, curves to the scroll saw, holes to the drill press — machines are means, fitness is the principle. Maintenance: replace blunt blades, sharpen bits, oil sliding parts as instructed, clean swarf after use and cover against dust. Equipment beyond repair is registered and disposed of as directed by the teacher; metal bodies are recycled, never binned as ordinary waste. For example, a blade with a hairline crack may snap and fly at speed — timely replacement is the cheapest insurance.
5Worked example Example
Example: the workshop has a new drill press, and the teacher asks you to write a pre-operation checklist the whole class can run through before use. Give four check groups with their contents.
- Power and controls → plug and cable undamaged; emergency stop and switch work properly
- Bit and chuck → correct bit for material and hole size; chuck tightened and the key removed; bit straight and uncracked
- Work and table → work clamped in the machine vice or fixtures; table locked at the right height; bench cleared of clutter
- Protection and surroundings → goggles on, covered shoes worn; hair tied, loose clothing secured; neighbouring students kept at a safe distance
- Answer: A complete pre-operation check covers power and controls, bit and chuck, work and table, and protection and surroundings — verified item by item before switching on. After starting, run the machine unloaded for a few seconds and listen for odd sounds; stay focused while drilling; brush away swarf only after a full stop; and at the end, switch off, remove the bit, clean the machine and log its use. A checklist works because it replaces memory with procedure — anyone following it reaches the same standard of safety.
6Common mistakes Mistakes
7Quick check Quick check
Q1What is a scroll saw best at? A. piercing thick steel plate B. cutting curves in thin board C. smoothing surfaces
Q2Why must the chuck key be removed immediately after fitting a bit?
Q3What should you do as the bit is about to break through the far side?
Q4Name three routine maintenance jobs for bench machines.
Q5How should equipment that is beyond repair be handled?
8Recap Recap
- Bench machines use motors for fast, accurate work — and carry higher risks
- A scroll saw's narrow blade cuts curves and interior openings in thin sheet
- A drill press spins bits into clamped work for accurate round holes
- Before use, check power, cutting tools, work-holding and protection
- Choose equipment to fit the job, maintain it regularly, dispose of it by procedure