So one of the most overlooked asspect of fasteners, Nuts and Washers.  I always have to try to remember what size relates to the size of the bolt.  See below

US NUT SIZE TABLE

Size	Diam.*		Height
	Hex Nut	Machine Screw Nut	Hex Nut	Jam Nut	Nylock Nut	Machine Screw Nut
0	-	5/32	-	-	-	3/64
1	-	5/32	-	-	-	3/64
2	-	3/16	-	-	9/64	1/16
3	-	3/16	-	-	9/64	1/16
4	-	1/4	-	-	9/64	3/32
6	-	5/16	-	-	11/64	7/64
8	-	11/32	-	-	15/64	1/8
10	-	3/8	-	-	15/64	1/8
12	-	7/16	-	-	5/16	5/32
1/4	7/16	7/16	7/32	5/32	5/16	3/16
5/16	1/2	9/16	17/64	3/16	11/32	7/32
3/8	9/16	5/8	21/64	7/32	29/64	1/4
7/16	11/16	-	3/8	1/4	29/64	-
1/2	3/4	-	7/16	5/16	19/32	-
9/16	7/8	-	31/64	5/16	41/64	-
5/8	15/16	-	35/64	3/8	3/4	-
3/4	1-1/8	-	41/64	27/64	7/8	-
7/8	1-5/16	-	3/4	31/64	63/64	-
1	1-1/2	-	55/64	35/64	1-3/64	-
* This is the diameter across the flats. It is also the size of wrench to use.