Core-print
A tapered boss on a pattern or model, indicating the place where a hole corresponding with it in size and shape must be made in the casting. A print of this description is frequently termed a "seating." These prints should always be as large as the intended hole, at the point of contact with the pattern, tapering a little from thence outwards, just sufficient for a clean draw from the sand.
That end of the core which enters the print is called the "print-end." When castings, as columns, pipes, etc., are cast horizontally, the prints which guide and support the core in that position are naturally styled "bearings." See SEATING.
Core-sand is sand possessing qualities that will favor the production of a good sound core with the minimum quantity of gas-producing substances in its composition; and that will leave the casting clean and free from scars, with comparatively no expense for labor. To that end sands should be chosen which contain the least possible proportion of alumina and organic matter. The requisite consistency can be temporarily imparted by substances which, while they stiffen the core sufficient for handling, are acted upon by the molten metal, burning the artificial substance out, and leaving the sand as incohesive as it was in its original state. Silica sands, beach, and river sands, are eminently useful for this purpose, and even indifferent clayey sands may be much improved, if subjected to the process of washing, to eliminate foreign substances there-from before using. See SAND-WASHING; FLOUR; MOLASSES; GLUE.