1/4 x 28 THREAD FORMING
(SAE J534)
A. 3/4″
B. 13/64″
C. 5/32″
Hex size. 3/8″
Material. 1215
Zinc Finish. Yellow/Clear
Type. 90°

The ¼”-28 SPL Special taper threads makes its own thread on soft metals.
The recommended hole size is 0.231”-0.235”.