Screw Distributor

Screws

Bayou City Bolt carries a wide variety of Machine, Tapping and Wood Screws. We keep hex head, round head and pan head in stock. Drill point screws as well as construction fasteners are available as well. We also stock specialty screws such as Tamperproof, Thread-Cutters and Set Screws.

  • Drill Point Screws
  • Tek Screws
  • Drywall Screws
  • Lag Screws
  • Machine Screws
  • Set Screws
  • Thread Cutting Screws
  • Thread Rolling Screws
  • Rolok
  • Tamperproof Screws
  • Thumb Screws
  • Wood Screws
  • U-Drive Screws

MACHINE SCREWS

The term Machine Screw typically refers to small diameter, general purpose screws. Machine Screw diameters range from #0 (1/64") up to #14 (1/4"). Machine screws are threaded to be used in a tapped hole, or with a nut to join two mating surfaces.

Additional Specification

TAPPING SCREWS

Tapping Screws, also known as Sheet Metal Screws have the ability to "tap" their own internal thread when driven into metallic and non-metallic materials. These sharp threads cut into a material such as sheet metal, plastic or wood. By cutting their own thread, they create a good thread fit which increases resistance to loosening while in service. The shank is usually threaded up to the head.

WOOD SCREWS

Wood Screws are formed in a similar manner to tapping screws. However, the thread length is approximately two-thirds the nominal length of the screw. The unthreaded portion of the shank is designed to slide through the top board (to prevent binding) so that it can be pulled tight to the board it is being attached to.

LAG SCREWS

Lag screws, also sometimes called lag bolts, are basically "large wood screws". A typical lag bolt can range in diameters from 1/4" to 1 1/4", and lengths from 1/4" to 6" or longer, with coarse threads similar to a wood-screw. The head is typically an external hex. Lag bolts are used to lag together lumber framing, to lag machinery feet to wood floors, and other heavy carpentry applications.

THREAD FORMING SCREWS

Thread forming screws, or Thread Cutters, were designed to extend Tapping Screws to thicker and/or harder materials. Thread Cutters have cutting flutes or edges at their point so that the screw will act as a tap and cut its own mating threads.

GOVERNING STANDARDS

ASME B18.6.3 Machine Screws, Tapping Screws, and Metallic Drive Screws (Inch Series)
ASME B18.6.1 Wood Screws (Inch Series)
ASME B18.6.4 Thread Forming & Thread Cutting Tapping Screws & Metallic Drive Screws (Inch Series)
ASME B18.2.1 Square, Hex, Heavy Hex, and Askew Head Bolts and Hex, Heavy Hex, Hex Flange, Lobed Head, and Lag Screws (Inch Series)
SAE J933 Mechanical & Quality Requirements for Tapping Screws

HEAD STYLES

Head Styles

DRIVE STYLES

Drive Styles

MACHINE SCREWS - US STANDARD

  Thread Diameter
Size & Thread per InchDecimalNearest Fraction
# 0-80 0.06" 1/64"
# 1-64 0.07" 5/64"
# 2-56 0.08" 3/32"
# 3-48 0.09" 7/64"
# 4-40 0.11" 7/64"
# 5-40 0.12" 1/8"
# 6-32 0.13" 9/64"
# 8-32 0.16" 5/32"
# 10-24 0.19" 3/16"
# 12-24 0.21" 7/32"
# 14-20 0.24" 1/4"

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MACHINE SCREW - METRIC

 Thread Diameter
Size & Thread PitchDecimal
M1.6-.35 .063"
M2.0-.40 .079"
M2.5-.45 .098"
M3.0-.50 .118"
M4.0-.70 .157"
M5.0-.80 .196"
M6.0-1.0 .236"
M8.0-1.25 .315"
M10-1.50 .393"
M12-1.75 .472"

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DRILL SIZES FOR THREAD ROLLING TAPPING

SCREWS AND TYPES D,F,G & T THREAD CUTTERS

Screw SizeMean Hole DiameterDrill SizeDrill Diameter
2-56 0.076 48 0.076
2-64 0.077 48 0.076
3-48 0.090 44 0.086
3-56 0.090 44 0.086
4-40 0.097 41 0.096
4-48 0.100 41 0.096
5-40 0.110 35 0.110
5-44 0.112 35 0.110
6-32 0.119 31 0.120
6-40 0.124 31 0.120
8-32 0.146 20 0.147
8-36 0.148 20 0.147
10-24 0.165 19 0.166
10-32 0.172 11/64 0.1719
12-24 0.192 11 0.191
1/4-20 0.221 2 0.221
1/4-28 0.230 2 0.221
5/16-18 0.281 K 0.281
5/16-24 0.290 K 0.281
3/8-16 0.339 R 0.339
3/8-24 0.353 R 0.339
7/16-14 0.397 X 0.397
7/16-20 0.411 X 0.397
1/2-13 0.457 29/64 0.4531
1/2-20 0.475 29/64 0.4531

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DRILL SIZES FOR TYPES AB, B, AND BP THREAD FORMING

TAPPING SCREWS AND TYPES BF & BT THREAD CUTTERS

Screw SizeMean Hole DiameterDrill SizeDrill Diameter
0-48 0.046 56 0.0465
1-42 0.059 53 0.0595
2-32 0.072 49 0.0730
3-28 0.084 45 0.0820
4-24 0.096 41 0.0960
5-20 0.107 36 0.1065
6-20 0.116 32 0.1160
7-19 0.129 30 0.1285
8-18 0.138 29 0.1360
10-16 0.159 21 0.1590
12-14 0.182 14 0.1820
1/4-14 0.211 4 0.2090
5/16-12 0.270 I 0.2720
3/8-12 0.333 Q 0.3320
7/16-10 0.386 W 0.3860
1/2-10 0.449 29/64 0.4531

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We offer the lowest minimums in the industry, and sell by the piece or in
bulk - you buy only the fasteners you need!

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