Thread geometry - British Association (BA)

All dimensions in inches unless otherwise stated.

	d1 - Minor thread diameter male d2 - Minor thread diameter female d3 - Pitch diameter d4 - Major diameter

Thread	Major diameter	Thread per inch	Pitch diameter	Minor diameter male thread
No. 16	0.03110	134	0.02630	0.02205
No. 15	0.03543	121	0.03016	0.02559
No. 14	0.03937	110	0.03358	0.02835
No. 13	0.04724	102	0.04094	0.03543
No. 12	0.05118	91	0.04413	0.03780
No. 11	0.05906	82	0.05122	0.04449
No. 10	0.06693	73	0.05811	0.05039
No. 9	0.07480	65	0.06496	0.05630
No. 8	0.08661	59	0.07579	0.06614
No. 7	0.09843	53	0.08634	0.07559

Thread	Major diameter	Thread per inch	Pitch diameter	Minor diameter male thread
No. 6	0.11024	48	0.09689	0.08504
No. 5	0.12598	43	0.11110	0.09803
No. 4	0.14173	38	0.12508	0.11063
No. 3	0.16142	35	0.14303	0.12677
No. 2	0.18504	31	0.16461	0.14685
No. 1	0.20866	28	0.18598	0.16614
No. 0	0.23622	25	0.21102	0.18898