US 4,498,361 AGranted

Broach manufacturing method

AssigneeEx-Cell-O Corporation

InventorWallace C. Grace

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Abstract

The broach manufacturing method includes a first turning operation in which the outer diameter of the puller portion, retriever portion and the toothed cutting portion are rough turned to within 0.030-0.050 inch of finished dimension. Also, in the first turning opertion, the cutting teeth are turned to include a gullet radius of finished dimension and an oversized hook angle intersecting therewith. Following a hardening treatment, the cutting teeth are turned to finished dimension in a second turning operation with the exception that the outer diameter and back-off angle of the finishing teeth are turned slightly oversize in the second turning operation followed by grinding to final dimension. The oversized hook angle of the cutting teeth is also nicked off during the second turning operation and blended with the gullet radius turned in the first turning operation. The turning operations are performed on a CNC lathe.

Claims6

Dependent claims

A method for making from tool stock a broaching tool with a puller portion adjacent one end, a retriever portion adjacent the other end and a cutting portion having a plurality of individual cutting teeth between the puller portion and retriever portion comprising

(a) turning the tool stock to machine the outer dimension of the puller portion, retriever portion and cutting portion to a preselected over-size dimension larger than the finished outer dimension of the tool and turning individual cutting teeth to have a gullet radius to finished dimension and a hook angle to an oversize dimension intersecting the gullet radius,
(b) then heat treating the tool stock turned in step (a),
(c) then turning the heat treated tool stock to machine the oversize outer dimension of the puller portion, retriever portion and at least a portion of the cutting portion of the tool stock to finished dimension and turning individual cutting teeth to face the hook angle to finished dimension and blend said hook angle with the gullet radius.

Dependencies are inferred from the claim text.