Pre Ream Drill Size

Pre Ream Drill for 2% Ream

Reamer Diameter
Drill for 2% Ream
Decimal Equivalent
9/16 (0.5625)
35/64
0.5513
1in (1.0000)
24.75MM
0.9800
63/64 (0.9844)
24.40MM
0.9647
31/32 (0.9688)
24.00MM
0.9494
61/64 (0.9531)
23.50MM
0.9340
15/16 (0.9375)
23.25MM
0.9188
59/64 (0.9219)
22.80MM
0.9035
29/32 (0.9062)
22.50MM
0.8881
57/64 (0.8906)
22.00MM
0.8728
7/8 (0.8750)
21.60MM
0.8575
55/64 (0.8594)
21.25MM
0.8422
27/32 (0.8438)
20.80MM
0.8270
53/64 (0.8281)
20.50MM
0.8115
13/16 (0.8125)
20.10MM
0.7963
51/64 (0.7969)
19.70MM
0.7810
25/32 (0.7812)
19.30MM
0.7656
49/64 (0.7656)
18.90MM
0.7502
3/4 (0.7500)
18.50MM
0.7350
47/64 (0.7344)
18.20MM
0.7197
23/32 (0.7188)
45/64
0.7044
45/64 (0.7031)
11/16
0.6890
11/16 (0.6875)
17.00MM
0.6738
43/64 (0.6719)
21/32
0.6585
21/32 (0.6562)
41/64
0.6431
41/64 (0.6406)
5/8
0.6278
5/8 (0.6250)
39/64
0.6125
39/64 (0.6094)
19/32
0.5972
19/32 (0.5938)
37/64
0.5820
37/64 (0.5781)
9/16
0.5665
35/64 (0.5469)
17/32
0.5360
17/32 (0.5312)
33/64
0.5206
33/64 (0.5156)
1/2
0.5053
1/2 (0.500)
31/64
0.4900
31/64 (0.4841)
12.0MM
0.4747
15/32 (0.4688)
11.6MM
0.4594
29/64 (0.4531)
11.2MM
0.4440
7/16 (0.4375)
10.8MM
0.4288
27/64 (0.4219)
10.4MM
0.4135
13/32 (0.4062)
10.0MM
0.3982
25/64 (0.3906)
9.6MM
0.3828
3/8 (0.3750)
9.25MM
0.3675
23/64 (0.3594)
S
0.3522
11/32 (0.3438)
8.5MM
0.3370
21/64 (0.3281)
8.1MM
0.3215
5/16 (0.3125)
7.75MM
0.3063
19/64 (0.2969)
7.3MM
0.2910
9/32 (0.2812)
I
0.2756
17/64 (0.2656)
6.5MM
0.2600
1/4 (0.250)
C
0.2450
15/64 (0.2344)
1
0.2297
7/32 (0.2188)
5.4MM
0.2144
13/64 (0.2031)
5.0MM
0.1990
3/16 (0.1875)
14
0.1838
11/64 (0.1719)
19
0.1685
5/32 (0.1562)
24
0.1532
9/64 (0.1406)
29
0.1378
1/8 (0.1250)
31
0.1225