Five free practice questions on band saws and power saws: block C of the Red Seal 429A Machinist exam, about 8 of its 135 questions. They are in the exam's format: four options, one correct answer. Answer each one before opening the explanation. No account, no email.
01The questions
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A band-saw blade has a wave set. What work is it mainly made for?
- Thick blocks of soft aluminum.
- Thin-wall tube and thin sheet.
- Large solid bars of mild steel.
- Plastics and wood at a fast feed.
Show the answer
B. Correct. In a wave set the teeth are bent in groups, gradually to one side and then the other. With the fine pitch it comes in, it keeps several teeth engaged and spreads the load on thin sections, so teeth do not catch on a thin wall and strip.
Why not the others
A. Thick aluminum needs a coarse, positive-rake (hook) tooth with large gullets to carry the long, soft chips. A wave set's fine pitch would load up with aluminum and stall.
C. Solid bar is usually cut with a raker-set blade (one tooth left, one right, one unset) in a coarser pitch. A fine wave-set blade on a large solid would pack its small gullets and cut slowly.
D. Plastics and wood are usually cut with a coarse skip-tooth blade with large gullets that clear chips quickly. A fine wave-set blade would clog, and the heat would melt or scorch the cut.
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A band-saw blade has just been butt-welded on the saw's welder. What is done to the joint next?
- It is flexed by hand to test it.
- It is ground flush with the band.
- It is annealed in the welder.
- It is quenched in cutting fluid.
Show the answer
C. Correct. The weld cools quickly against the welder's jaws and comes out hard and brittle. Annealing it in the welder's annealing jaws (reheated, then cooled slowly) restores toughness; only then is it ground flush to the blade thickness.
Why not the others
A. Flexing an un-annealed weld is the quickest way to snap it. The joint is annealed and ground before the band is flexed or put on the wheels.
B. Grinding is the right step at the wrong time. Straight off the welder the joint is hard and brittle and can crack when ground or flexed. Anneal it first, then grind it flush to the blade thickness.
D. Quenching would make the weld harder and more brittle still, which is exactly the problem after welding. The joint needs reheating and a slow cool so it can flex around the wheels.
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A short piece has to be clamped at one end of the saw vise jaws. What keeps the movable jaw from cocking so the piece is held square?
- Soft jaw covers fitted to both vise jaws.
- A thin shim between the piece and the fixed jaw.
- A spacer of equal size at the other end.
- Extra vise pressure on the short piece.
Show the answer
C. Correct. With work at one end only, the movable jaw pivots on it and grips on an edge. A spacer of the same thickness at the other end keeps the jaw parallel to the fixed jaw, so the piece is clamped flat and square to the blade.
Why not the others
A. Soft jaw covers protect finished surfaces from marking, but the movable jaw still pivots about the short piece. A spacer of equal size at the other end keeps the jaws parallel.
B. A shim at the fixed jaw tilts the piece out of square and does nothing for the open end of the movable jaw, which still swings in. Fill the gap at the other end of the jaws.
D. More pressure makes the jaw cock further around the short piece, so it is gripped on one edge and can still shift or twist in the cut. Support the open end of the jaw instead.
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A short length of 40 mm round bar must be cut across on a vertical band saw. How should it be held?
- Between two parallels held by hand.
- Clamped in a V-block or work clamp.
- Against the rip fence, fed with a push block.
- Flat on the table, held firmly by hand.
Show the answer
B. Correct. The blade cuts downward, and on a round bar that force rolls the work, which can grab the bar, twist the band and pull the hands toward the blade. A V-block or clamp stops the bar turning and keeps the hands clear.
Why not the others
A. Two hand-held parallels do not lock a round bar against rotation, and they bring the hands close to the blade. A V-block or clamp holds the bar securely.
C. The fence guides the work in a straight line but does not stop a round bar rotating, and a push block is for flat work. The bar can still roll and grab the blade.
D. A firm grip does not stop a round bar rolling once the downward cutting force catches it; the bar can spin, snap the blade and drag fingers into the cut. Hold round stock in a V-block or clamp.
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A sawn and filed outside corner must have a 6 mm radius. How is the profile checked?
- With a steel rule across the corner at 45°.
- Against a 6 mm drill shank, sighting for light.
- With a square on the two adjacent faces.
- With a 6 mm radius gauge, sighting for light.
Show the answer
D. Correct. The concave end of a radius gauge fits an outside (convex) corner. Held square to the faces with a light behind, it shows any gap between gauge and work, so the shape and size of the radius are checked in one look.
Why not the others
A. A rule across the corner measures how much was taken off, not the shape of the curve; very different profiles can give the same reading. A radius gauge checks the form itself.
B. A 6 mm drill is 6 mm across, so its shank has a 3 mm radius, half the one called for. It also suits only an inside (concave) corner; against an outside corner it touches at a single point and shows nothing about the radius.
C. A square checks that the two faces are at 90°, which they can be whatever the corner radius is. It says nothing about the radius between them.
02Answer key
| Question | Answer | Sub-task |
|---|---|---|
| Q1 | B | Selects saw blades |
| Q2 | C | Installs saw blades |
| Q3 | C | Sets up workpiece on power saw |
| Q4 | B | Saws straight and angle cuts |
| Q5 | D | Cuts irregular shapes |
03What block C covers
Block C covers cut-off and contour sawing on power saws, mainly horizontal and vertical band saws: choosing the saw and the blade, tooth pitch and set, installing and breaking in a blade, band speeds and feeds, guide and vise adjustments, holding the workpiece, straight and angle cuts, and sawing irregular shapes to a layout line.
The Red Seal Occupational Standard names this block “Machines using power saws”. It carries 5.9% of the exam, about 8 of the 135 questions, split across two tasks. The share column is each task's weight within the block, as the standard publishes it.
| Task and its sub-tasks | Share of block |
|---|---|
| Sets up power saws Selects power saw types; Selects saw blades; Installs saw blades; Selects power saw speeds and feeds; Makes power saw adjustments; Sets up workpiece on power saw | 63% |
| Operates power saws Saws straight and angle cuts; Cuts irregular shapes | 37% |
04What the questions turn on
Tooth pitch from the wall thickness
Thin sections need enough teeth in the cut. If the blade maker calls for three teeth in contact, divide three by the wall thickness to get the minimum teeth per inch, then take the coarsest blade that meets it for chip room.
Break in a new blade
A new blade's tooth tips are very sharp and fine. Run the first cuts at the normal band speed with the feed reduced, which hones the tips instead of chipping them, then bring the feed up gradually.
Guide arms close to the work
The blade is supported only at its guides, and the span between them is free to twist. Setting both guide arms just clear of the work shortens that span and keeps the cut straight and square.
Band speed is rim speed
The band travels at the rim speed of the drive wheel, so band speed in m/min is π times the wheel diameter in millimetres times rpm, divided by 1 000. It is the metric rpm formula rearranged.
05The other blocks
The 429A exam has eight blocks. Each has its own page of free questions:
The 429A Machinist practice exam page describes the full question bank. How these questions are written and checked: how our questions are made. Found a mistake? Tell us and we will fix it.