Page 148 - Michigan Drill

Interchangeable

Pilot Counterbores

High Speed Steel
COUNTERBORES Short Series Straight Shank Taper Shank

For use with interchangeable Pilots
Used to enlarge the openings of a hole to allow room for the head
of a screw. Also for general purpose counterboring and spot facing.
List No. 500 – Straight Shank
List No. 501 – Taper Shank
Size Pilot Range of Number Overall Shank 500 Price Morse 501 Price
Hole Size Pilot Sizes of Flute Length Diameter Each Taper No. Each
11/64 3/32 3/32 - 1/2 3 3 11/64 28.80 — —
3/16 3/32 3/32 - 1/2 3 3 15/64 28.80 1 32.58
13/64 3/32 3/32 - 1/2 3 3 15/64 28.80 1 23.58
7/32 3/32 3/32 - 1/2 3 3 15/64 28.80 1 32.58
15/64 3/32 3/32 - 1/2 3 3-13/16 15/64 31.10 — —
1/4 3/32 3/32 - 1/2 3 3-13/16 15/64 30.15 1 32.58
17/64 3/32 3/32 - 1/2 3 3-13/16 17/64 31.10 — —
9/32 3/32 3/32 - 1/2 3 3-13/16 17/64 30.15 1 33.48
19/64 3/32 3/32 - 1/2 3 3-13/16 17/64 31.97 — —
5/16 3/32 3/32 - 1/2 3 3-13/16 19/64 30.96 1 33.48
21/64 3/32 3/32 - 1/2 3 3-13/16 19/64 31.68 — —
11/32 3/32 3/32 - 1/2 3 3-13/16 5/16 31.68 1 33.48
23/64 3/32 3/32 - 1/2 3 3-13/16 5/16 31.68 — —
3/8 5/32 9/64 - 17/36 3 4-1/16 5/16 31.68 1 33.48
25/64 5/32 9/64 - 17/36 3 4-1/16 3/8 32.63 — —
13/32 5/32 9/64 - 17/36 3 4-1/16 3/8 33.70 1 35.55
27/64 5/32 9/64 - 17/36 3 4-1/16 3/8 33.70 — —
7/16 5/32 9/64 - 17/36 3 4-1/16 3/8 33.70 1 35.55
29/64 5/32 9/64 - 17/36 3 4-1/16 3/8 37.80 — —
15/32 3/16 3/16 - 1-1/8 3 4-5/16 7/16 35.37 1 37.26
31/64 3/16 3/16 - 1-1/8 3 4-5/16 7/16 35.37 — —
1/2 3/16 3/16 - 1-1/8 3 4-5/16 7/16 35.37 1 37.26
33/64 3/16 3/16 - 1-1/8 3 4-5/16 1/2 41.63 — —
17/32 3/16 3/16 - 1-1/8 3 4-5/16 1/2 39.33 1 41.63
35/64 3/16 3/16 - 1-1/8 3 4-5/16 1/2 41.18 — —
9/16 3/16 3/16 - 1-1/8 3 4-5/16 1/2 39.33 1 41.63
37/64 3/16 3/16 - 1-1/8 3 5-1/8 1/2 43.42 — —
19/32 3/16 3/16 - 1-1/8 3 5-1/8 1/2 42.08 2 44.91
39/64 3/16 3/16 - 1-1/8 3 5-1/8 1/2 44.10 — —
5/8 3/16 3/16 - 1-1/8 3 5-1/8 1/2 42.08 2 44.91
41/64 3/16 3/16 - 1-1/8 3 5-1/8 1/2 46.98 — —
21/32 3/16 3/16 - 1-1/8 3 5-1/8 1/2 46.44 2 48.51
43/64 3/16 3/16 - 1-1/8 3 5-1/8 1/2 49.32 — —
11/16 3/16 3/16 - 1-1/8 3 5-1/8 1/2 46.44 2 48.51
45/64 1/4 1/4 - 1-3/8 3 5-3/8 1/2 50.40 — —
23/32 1/4 1/4 - 1-3/8 3 5-3/8 1/2 48.33 2 50.27
47/64 1/4 1/4 - 1-3/8 3 5-3/8 1/2 52.20 — —
3/4 1/4 1/4 - 1-3/8 3 5-3/8 1/2 48.33 2 50.27
49/64 1/4 1/4 - 1-3/8 3 5-3/8 5/8 51.08 — —
25/32 1/4 1/4 - 1-3/8 3 5-3/8 5/8 51.08 2 53.42
51/64 1/4 1/4 - 1-3/8 3 5-3/8 5/8 54.81 — —
13/16 1/4 1/4 - 1-3/8 3 5-3/8 5/8 49.41 2 53.42
53/64 1/4 1/4 - 1-3/8 3 5-3/8 5/8 55.80 2 64.60
27/32 1/4 1/4 - 1-3/8 3 5-3/8 3/4 54.23 2 55.48
55/64 1/4 1/4 - 1-3/8 3 5-3/8 3/4 59.40 — —
7/8 1/4 1/4 - 1-3/8 3 5-3/8 3/4 51.84 2 55.48
57/64 1/4 1/4 - 1-3/8 3 5-3/8 3/4 61.20 — —
29/32 1/4 1/4 - 1-3/8 3 6-1/8 3/4 54.45 3 58.62
59/64 1/4 1/4 - 1-3/8 3 6-1/8 3/4 64.80 — —
15/16 1/4 1/4 - 1-3/8 3 6-1/8 3/4 54.45 3 58.62
61/64 5/16 5/16 - 1-3/8 3 6-3/8 3/4 67.50 — —
31/32 5/16 5/16 - 1-3/8 3 6-3/8 3/4 64.89 3 66.99
63/64 5/16 5/16 - 1-3/8 3 6-3/8 3/4 75.15 — —
1 5/16 5/16 - 1-3/8 3 6-3/8 3/4 64.89 3 66.99
1-1/32 5/16 5/16 - 1-3/8 3 6-3/8 3/4 76.23 3 75.37
1-1/16 5/16 5/16 - 1-3/8 3 6-3/8 3/4 73.26 3 75.37
1-3/32 5/16 5/16 - 1-3/8 3 6-3/8 1 73.26 3 79.55
Continued on Next Page 
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