of the terminal post cavities 18 and connector post cavities 19 respectively the open sides of the coolant cavities are closed by plates 83 and 84 welded therein coolant is circulated through passages 78 and 79 after the plate lugs have been immersed in the molten metal cavities 21 by means not shown upon solidification of the molten metal as lug connecting straps the coolant liquid is expelled from the passages 78 and 79 and the passages are dried as by passing air therethrough an extension of the terminal post cavity 18 beyond the thickness of insert 12 is accomodated by an extension 85 that extension also provides a guide for terminal post knockout pin 86 connector post knockout pins 87 are guided in bores in bosses 82 to aid the removal of those posts and their integral lug connector straps the knockout pins 86 and 87 are operated in unison by raising knockout table 88 after solidification of the elements cast in mold cavities 18 19 and 21 it can be appreciated that the advantage of contact areas between the base 11 and inserts 12 and 13 which are flat and horizontal as at 37 40 mating with 46 49 and at 41 44 mating with 51 54 to provide the advantage of a broad area joint secured in compression at regular intervals by bolts 55 and enabling.