Machine Screw Size

Number of Threads Per Inch

Minor Dia.

Tap Drills

Clearance Hole Drills

Aluminum, Brass & Plastics

75% Thread 

Stainless Steel, Steels & Iron

50% Thread

All Materials

Close Fit

Free Fit

No. or Dia.

Major Dia.

Drill Size

Decimal Equiv.

Drill Size

Decimal Equiv.

Drill Size

Decimal Equiv.

Drill Size

Decimal Equiv.

3/4

.7500

10

.6273

21/32

.6562

11/16

.6875

49/64

.7656

25/32

.7812

16

.6733

11/16

.6875

45/64

.7031

20

.6887

45/64

.7031

23/32

.7188

13/16

.8125

20

.7512

49/64

.7656

25/32

.7812

53/64

.8281

27/32

.8438

7/8

.8750

9

.7387

49/64

.7656

51/64

.7969

57/64

.8906

29/32

.9062

14

.7874

13/16

.8125

53/64

.8281

20

.8137

53/64

.8281

27/32

.8438

15/16

.9375

20

.8762

57/64

.8906

29/32

.9062

61/64

.9531

31/32

.9688

1

1.000

8

.8466

7/8

.8750

59/64

.9219

1-1/64

1.0156

1-1/32

1.0313

12

.8978

15/16

.9375

61/64

.9531

20

.9387

61/64

.9531

31/32

.9688

1-1/16

1.0625

18

.9943

1.000

1.000

1-1/64

1.0156

1-5/64

1.0781

1-3/32

1.0938

1-1/8

1.1250

7

.9497

63/64

.9844

1-1/32

1.0313

1-9/64

1.1406

1-5/32

1.1562

12

1.0228

1-3/64

1.0469

1-5/64

1.0781

18

1.0568

1-1/16

1.0625

1-5/64

1.0781

1-3/16

1.1875

18

1.1193

1-1/8

1.1250

1-9/64

1.1406

1-13/64

1.2031

1-7/32

1.2188