MARYLAND METRICS
THREAD DATA CHARTS

Size	Threads per inch	Outside Dia.	Core Dia.	Pitch	Depth	Radius	Tapping drill	Clearance drill
		inch	inch	inch	inch	inch	mm	mm
				p		r
16	56 RH	0.0735	0.0545	0.0179	0.0095	0.0030	1.5 mm	2 mm
15	56 RH	0.0825	0.0635	0.0179	0.0095	0.0030	1.7 mm	2.2 mm
14	56 RH	0.0905	0.0715	0.0179	0.0095	0.0030	1.9 mm	2.4 mm
13	56 RH	0.1025	0.0835	0.0179	0.0095	0.0030	2.2 mm	2.7 mm
12	56 RH	0.1145	0.0955	0.0179	0.0095	0.0030	2.55 mm	3 mm
1/8"	40 RH	0.1250	0.0984	0.0250	0.0133	0.0041	2.65 mm	3.4 mm
11	44 RH	0.1291	0.1049	0.0227	0.0121	0.0038	2.8 mm	3.5 mm
10	40 RH	0.1423	0.1157	0.0260	0.0133	0.0041	3.1 mm	3.8 mm
5/32"	32 RH	0.1563	0.1231	0.0312	0.0166	0.0052	3.4 mm	4.2 mm
9	40 RH	0.1583	0.1317	0.0250	0.0133	0.0041	3.5 mm	4.3 mm
8	32 RH	0.1776	0.1444	0.0312	0.0168	0.0052	3.9 mm	4.7 mm
3/16"	32 RH	0.1875	0.1543	0.0312	0.0166	0.0052	4.1 mm	5.0 mm
7/32"	26 RH	0.2188	0.1778	0.0385	0.0205	0.0064	4.8 mm	5.8 mm
1/4"	26 RH	0.2500	0.2090	0.0385	0.0205	0.0064	5.5 mm	6.6 mm
17/64"	26 RH	0.2656	0.2246	0.0385	0.0205	0.0064	5.0 mm	7.0 mm
9/32"	26 RH	0.2813	0.2403	0.0385	0.0205	0.0064	6.4 mm	7.4 mm
5/16"	26 RH	0.3125	0.2715	0.0385	0.0205	0.0064	7.2 mm	8.3 mm
3/8"	26 RH	0.3750	0.3340	0.0385	0.0205	0.0064	8.8 mm	9.9 mm
7/16"	26 RH	0.4375	0.3965	0.0385	0.0205	0.0064	10.4 mm	11.5 mm
7/16"	20 RH	0.4375	0.3843	0.5000	0.0266	0.0083	10.3 mm	11.5 mm
1/2"	26 RH	0.5000	0.4590	0.0385	0.0205	0.0064	12.0 mm	33/64"
1/2"	20 RH	0.5000	0.4590	0.0500	0.0266	0.0083	11.9 mm	33/64"
9/16"	26 RH	0.5625	0.5215	0.0385	0.0205	0.0064	13.5 mm	37/64"
9/16"	20 RH	0.5625	0.5093	0.0500	0.0266	0.0083	13.4 mm	37/64"
5/8"	26 RH	0.6250	0.5840	0.0385	0.0205	0.0064	15.0 mm	41/64"
5/8"	20 RH	0.6250	0.5719	0.0500	0.0266	0.0083	14.75 mm	41/64"
11/16"	26 RH	0.6875	0.6465	0.0385	0.0205	0.0064	21/32"	18 mm
11/16"	20 RH	0.6875	0.6343	0.0500	0.0266	0.0083	16.5 mm	18 mm
3/4"	26 RH	0.7500	0.7090	0.0385	0.0205	0.0064	23/32"	19.5 mm
3/4"	20 RH	0.7500	0.6968	0.0500	0.0266	0.0083	18.0 mm	19.5 mm
7/8"	24 RH	0.8750	0.8306	0.0417	0.0222	0.0070	21.5 mm	23 mm
31/32"	30 RH	0.9688	0.9332	0.0333	0.0178	0.0066	24 mm	25 mm
1"	24 RH	1.0000	0.9556	0.0417	0.0222	0.0070	31/32"	26 mm
1 1/8"	26 RH	1.1250	1.0840	0.0385	0.0205	0.0064	1 3/32"	29 mm
1.29"	24 LH	1.2900	1.2456	0.0417	0.0222	0.0070	32 mm	1 5/16"
1.37"	24 RH	1.3700	1.3256	0.0417	0.0222	0.0070	34 mm	35.5 mm
1.37"	24 LH	1.3700	1.3256	0.0417	0.0222	0.0070	34 mm	35.5 mm
1.45"	26 RH	1.4500	1.4090	0.0385	0.0205	0.0064	1 27/64"	37.5 mm
1.45"	26 LH	1.4500	1.4090	0.0385	0.0205	0.0064	1 27/64"	37.5 mm
1 9/16"	24 LH	1.5620	1.5181	0.0417	0.0222	0.0070	1 17/32"	1 19/32"
1 5/8"	24 RH	1.6250	1.5805	0.0417	0.0222	0.0070	40.5 mm	42 mm

Notes: RH = Right Hand     LH = Left Hand     r = p x 0.1666     D = p x 0.5327

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IMPERIAL WIRE GAUGE (IWG)
spoke thread data
No picture currently available

Size	Threads per inch	Outside Dia.	Core Dia.	Pitch	Depth	Radius	Tapping drill
		inch	inch	inch	inch	inch
				p		r
17 IWG	62	0.056	0.0388	0.01613	0.0086	0.002687	No 61
16 IWG	62	0.064	0.0468	0.01613	0.0086	0.002687	3/64"
15 IWG	62	0.072	0.0548	0.01613	0.0086	0.002687	No 54
14 IWG	62	0.08	0.0628	0.01613	0.0086	0.002687	1.60mm
13 IWG	56	0.092	0.073	0.0179	0.0095	0.002982	No 49
12 IWG	44	0.104	0.0798	0.0227	0.0121	0.00378	No 46

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