slots and their distribution and whether they are through slots such as those in the side and end walls or tee slots into the thickness of the base is quite immaterial a particular pattern may be preferred in a particular kind of work and a different pattern in another kind of work the purpose of all of the slots in the side walls and end walls is to facilitate the attachment of clamp means for securing the workpiece to the vee block or to one or other of the side or end walls and or of securing the block to a machine tool according to the nature of the work in hand fig2 shows another embodiment again the top is provided with a pair of vee recesses 30 which have co planar surfaces in this case one side wall 32 and the base 34 are through slotted and instead of providing two side walls and two end walls all of which are mutually at right angles to one another and to the base only a single side wall and two end walls 36 are provided in such manner the open side lying between the two vee block parts facilitates ingress to the base slots and to a portion of the workpiece lying between the vee blocks where they are used in this case also the side wall and base have half slots 38 opening to the end face and these may be.