Knife File, Cut 2

Excel knife file, Cut 2

A file with a wedge-shaped section, which tapers from the wider side into a sharp edge, hence the name knife. The cut is marked Cut 2, that is a medium coarseness, where a lower number means coarser teeth and a higher one finer teeth.

Why a wedge section is needed

A model has plenty of places where two surfaces meet at a sharp angle. A wing root, the valley between the fuselage and a leading edge, the corner between a superstructure and a deck, the gap under a fender. A flat file braces into such a corner with its face, makes a groove with its edge and leaves the bottom of the gap untouched. A knife file, by contrast, reaches right down into the angle, because its edge follows the very shape you need to clean out.

Precision instead of force

A sharp edge removes material in a concentrated way over a small area, so it is easy to go deeper with it than you planned. Work with a light hand, therefore, and check often. It pays to tape over the neighboring surface you do not want to touch. The file will catch the tape now and then, but the plastic underneath stays untouched.

Use

• Lead the file on the stroke away from you along the gap, not across it.
• Protect the neighboring surface with tape, as a sharp edge slips easily.
• Work little by little and check against the light as you go to see how much is already gone.
• Do not use the edge as a pry bar, as a wedge profile can break at a thin point.
• Clean the teeth as you go, as a clogged file stops removing material and starts to slide.

Who it is for

For builders of aircraft, ships and vehicles, where sharp inner angles occur most, and for anyone who wants this profile covered among their individual files too.

The file has a sharp edge and sharp teeth, so protect your fingers. Do not inhale the dust and work in a ventilated room.