This project is intended to serve a number of possible functions and can be used as a classroom artifact and or a working drill press.

The project can be used as an example of a rack and pinion mechanism converting rotary motion into linear motion. It also employs smart grease to make the mechanism drag a little so that should the press handle be released the drill does not fall down the pillar and smash the drill into the wood.

At Keystage 3 I would be particularly drawing the students attention the the design features of this product. The mechanism and its purpose is the first step but I would then move on to some of the more subtle aspects of the design. The unit is designed to be both left and right handed in it's operation, i.e. the operating handle can be bolted on either side. Despite 3mm acrylic having low mechanical properties the design is made to take these deficiencies into account. Firstly, the base has an inner support wall in the shape of a X that is designed to allow the operator to press down on the workpiece without cracking or deflecting the workarea. Also under the drill a hole has been made in the workarea to allow the bit to protrude through the circuit board without having to machine the workarea, this can sometimes result in a broken bit.

Also the X cross support has been rebated to ensure that it does not interfere with the drill as it pokes out of the back of the work.

When you look at the column that supports the drill it is worth pointing out that three of these sides actually poke all the way through to the base thus adding rigidity to the tower as it supports the weight of the drill which is significantly off centre from the column. This leverage causes a bending moment, some of this force being transmitted to the work surface and some to the underside.

Finally the sliding bolt at the back of the column is designed to stop any twisting of the carriage around the gear wheel. When the first design was made it was apparent that on the up stroke the unit had a tendency to tilt forwards and on the down stroke a tendency to tilt backwards, this in itself would have been a minor problem apart from when the drill was fully inserted in a hole the change in direction as you pulled the drill out was causing the drill to bend and occasionally on the .8mm drill break. This also takes a lot of pressure off the gears and will subsequently extend their life.

At keystage 4 I would review the design and expect pupils to be able to offer suggestions of better materials for the drill task and argue why they had selected them.

At AS level I would be looking to discuss the flaws of acrylic and the further defects in the project in depth, with a view to designing a market competitor. What materials could be used as alternatives. What mechanisms would supply the linear motion without the complexity of a rack and pinion.