Cleaving is done by driving a wedge between the fibres of a log, so as to split fibres apart along their weakest path. This work may appear strenuous, but is far less effort than rip sawing by hand. It is first done radially, to split the log into wedged segments. Timbers with
medullary rays, such as
oak, may be hard to split through these radial rays and so careful alignment is made to split between them. Segments are halved symmetrically at each step, as this encourages them to split more evenly than attempting to cleave off thin sheets repeatedly from one end. Cleaving usually begins from one end of a log, by driving the cleaving axe or a splitting wedge into the end of the log. It is driven further by use of a
mallet or
froe club. As always, a
hammer should be avoided when striking a hard steel tool, as it damages the tool by mushrooming it and may even cause cracking. A short log may be split entirely from one end, a long log will require an initial split to be extended along the log by the use of axe or wedges, driven in from the sides. Short logs are cleaved vertically, long ones horizontally. The ability to use several tools at once makes the use of an axe and wedges capable of cleaving far heavier logs than a
froe. The froe must also be used gradually from one end, the axe (or wedges) may enter the log from the side. The froe does however have a wider blade, and so may give a more precisely flat surface when cleaving wide timber, such as for
roofing shingles. It is common to start cleaving a log with an axe, finish the first heavy splits with wedges, then use a froe to make the finished items. == Related tools ==