To help you when the MDF or hardboard backing board seems to be too thick.
The
TRYMBLOCK tool is hand made in hardwood. A utility 507 or an SM-10A blade, 515, is set at an angle inside it.
A slot in one side allows your hardboard or MDF board to slide in. Pulling it firmly towards you shaves off a strip of the board quickly and neatly, to leave a neat bevel. This is repeated around all four sides.
The bevelled edges allow you to insert points to hold the back in place.
Tip: when you receive it, spend a few moments giving the edges a quick rub over with a piece of fine sandpaper. This makes a good tool even better.