The die illustrated in [Fig. 11] is for a part that is used as a swinging weight, shown in [Fig. 12]. The upper part of the piece is made from a sheet steel punching, so as to lighten this part of the piece as well as to give increased strength, especially at the hole at the pivoted end of the work. The cast portion of the piece is slotted lengthwise, as the illustration shows; and three holes pass through the casting, piercing the sides of the slot. In addition to showing the method of making dies for inserted pieces, this die shows the principles of simple coring.
Fig. 11. Casting-die for Making Castings with Inserted Pieces like that shown in [Fig. 12]
In making this die, two machine-steel blanks are planed up for the upper and lower halves of the die, A and B, the lower die being made nearly twice as thick as the upper die because it is in this part that the most of the die-cavity will be made. In this lower half of the die the stock is milled out to the same shape as the outline of the plan view of the casting, being carried down to the exact depth of the thickness of the casting. From the wide end of this recess the stock is milled or shaped out in a parallel slot to the outside of the die-block. At the bottom of the side of this wide slot are T-slots to guide the slide E that is to work in this opening. The side is milled and fitted to the T-slots and opening in the die, but is left considerably longer than the finish size. Next, the slide is mounted on the faceplate of a lathe and turned out on the end with the proper radius and a tongue to form the slot that is to be in the curved end of the casting. At the outer end of the slide is left a lug that is drilled and tapped for the operating lever F that reciprocates the slide, using the stud in bracket K as a fulcrum.
Two pieces of machine steel are next shaped and finished up to form the chamfered part of the casting and to locate the inserted steel punching in the die. The combined thickness of these pieces C and D is equal to the thickness of the casting, less the thickness of the inserted piece. It is now an easy matter to seat section D in the bottom of the milled part of the lower die-half, and to locate section C in its proper position on the upper half. A pilot pin M is fitted in D to hold the steel punching in position by means of the hole that is in the extreme upper end of the punching. The pilot pin extends through this hole into a corresponding hole in section C. At the lower end of the steel part that is inserted, there are two holes the object of which is to secure the punching to the die-casting, for the molten metal runs through these holes, practically riveting the die-casting to the inserted piece.
Fig. 12. Die-cast Weight with Inserted Sheet-steel Punching
Provision has now been made for holding the sheet-metal part that is to be inserted, and the cavity has been completed for the casting, including the tongue at the end; it now remains to describe the manner of forming the holes that pierce the casting through the slotted portion. In the lower die-half the positions of the three holes H are laid out, drilled and reamed. Then, with the two die-halves together and the slide clamped at its inner position, the holes are transferred through the slide and the upper die. This being done, it is an easy matter to make core pins and drive them into the upper die at the two end holes, the center hole being taken care of by the sprue cutter L that will be described later. The core pins should be a nice sliding fit through the slide and in the holes in the lower die, into which they should extend from a quarter to half an inch. In addition to coring the holes, these pins act as a lock to hold the slide E in its proper position at the time of casting.
The sprue cutter L is most conveniently operated in the center hole, thus doing away with the core pin that would otherwise be required. The sprue cutter needs little description in this die, for as in the slide die, it is merely a plain round rod that fits closely in the holes through the dies and slide. The ejector mechanism is the same in this die as in the dies already described; therefore further description is unnecessary.