Core-print
The Encyclopedia of Founding (1892)
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.
What Has Changed in the Last Century
The definition given by The Encyclopedia of Founding in 1892 is still the one used on the shop floor: a core print is the projection on the pattern that forms a seat in the sand to locate and support the core, and horizontal supports are still called bearings. What has moved is everything around it. The molasses, flour and glue binders the entry recommends have been displaced by resin systems — shell or Croning cores from the 1940s, sodium-silicate/CO2 from the 1950s, and amine-cured cold-box from the late 1960s — and cores are now commonly printed directly from a digital model on a binder-jetting sand printer, with no pattern and so no core print at all. The draft angle and the print-end, though, are drawn into CAD models today for exactly the reasons the 1892 writer gives.
Written for this edition, 2026.