Tub
The rectangular wooden trough over which some brass-moulders ram their flasks is by them called a tub. If iron slides are fastened on the inside, lengthwise, a few inches from the top, a frame can rest thereon to hold the flasks. By this means the rammed flask may be slided across or along the tub into any convenient position without bearing up its weight--a great convenience when the work is prolonged.
Tube-vents are vent-connections made with tubes in such a manner as to make it impossible for any metal to insinuate itself therein. If the gas from one core must be made to pass off by the way of another through a connecting core, the operation is made absolutely safe by placing a tube midway at the junction; or if a vent must be led from a core remote from the outside, as in a set of steam-way cores, tubes inserted in the vents, long enough to reach the distance, make it a safe operation. See VENTING.