Fig. 18 shows a partially completed flow chart for making a wooden photo frame. The timber has been selected for its working properties and appearance. Diff...

(a) A suitable operation for the box labelled A: [1]

Glue and assemble the mitre joints (or: apply wood glue and clamp the frame together). This is the logical next step after the mitre joints have been cut and checked for accuracy. PVA wood glue is applied to the mitre surfaces, the four pieces are assembled into the rectangular frame shape, and the assembly is held in a picture-frame clamp or corner clamps until the adhesive sets. Other acceptable answers include sanding the joints smooth or applying a surface finish, since these are valid subsequent operations.

(b) Purpose of the decision box: [1]

The decision box (diamond shape) represents a quality check point where the accuracy of the mitre joints is inspected before proceeding. If the joints fit accurately ("Yes"), the process continues forward to the assembly stage (box A). If they do not fit accurately ("No"), the flow loops back to the "Cut mitre joints" step so the joints can be re-cut or adjusted. This feedback loop ensures that only components meeting the required standard progress to the next stage, preventing a poorly fitting joint from being glued permanently into an inaccurate frame.

(c) One quality check after the frame is assembled: [1]

Check that the frame is square by using a try square at each corner or by measuring the two diagonals (if they are equal, the frame is square). Other valid checks include: verifying the overall dimensions match the specification using a steel rule; performing a visual inspection for gaps in the joints or surface defects; checking the frame lies flat on a known flat surface (no twist or warp).