Lab Inventory: Fasteners

The following tables may help you identify commonly used parts we have available in the lab supply.

For a searchable index of all lab parts, please see Physical Computing Lab Inventory.

For a more complete systematic table of the mechanical parts, please see PhysComp Lab Mechanical Parts Chart.

Button Head Socket Cap Screws

Button Head Socket Cap screws feature a rounded head and hex drive socket. The first parameter is the thread, the second is the length, measured from under the head. M3 is a metric size with a nominal thread diameter of 3 mm, and the length is in millimeters. 1/4-20 is an inch size with a nominal thread diameter of 0.25 inch and a length in inches.

M3 Metric Button Head Hex-Drive Screws

Size	Lab Part #	Description
M3 x 6	Lab Part 1832	18-8 Stainless Steel Button Head Hex-Drive Screw
M3 x 10	Lab Part 1829	18-8 Stainless Steel Button Head Hex-Drive Screw
M3 x 14	proposed	18-8 Stainless Steel Button Head Hex-Drive Screw, McMaster-Carr Part 92095A168
M3 x 20	Lab Part 1828	18-8 Stainless Steel Button Head Hex-Drive Screw
M3 x 30	Lab Part 1826	18-8 Stainless Steel Button Head Hex-Drive Screw
M3 x 40	Lab Part 1822	18-8 Stainless Steel Button Head Hex-Drive Screw
M3 x 50	Lab Part 1820	18-8 Stainless Steel Button Head Hex-Drive Screw

Other Metric Button Head Socket Cap Screws

Size	Lab Part #	Description
M4 x 16	Lab Part 1819	Black-Oxide Button Head Hex-Drive Screw
M5 x 16	Lab Part 1821	Black-Oxide Button Head Hex-Drive Screw

1/4-20 (Inch) Button Head Socket Cap Screws

Size	Lab Part #	Description
1/4-20 x 0.5	Lab Part 1764	18-8 Stainless Steel Button Head Hex-Drive Screw
1/4-20 x 0.75	Lab Part 1762	18-8 Stainless Steel Button Head Hex-Drive Screw
1/4-20 x 1.0	Lab Part 1760	18-8 Stainless Steel Button Head Hex-Drive Screw
1/4-20 x 1.5	Lab Part 1758	18-8 Stainless Steel Button Head Hex-Drive Screw
1/4-20 x 2.0	Lab Part 1756	18-8 Stainless Steel Button Head Hex-Drive Screw
1/4-20 x 3.0	Lab Part 1754	18-8 Stainless Steel Button Head Hex-Drive Screw

Other M3 Fasteners

Plastic screws are frequently used to mount electronics. These M3x16 slotted cheese-head screws fit through the Arduino mounting holes. Lab Part 6051

These inserts can be pressed into a 4.0 mm wood or plastic hole to provide a precision M3 threaded hole. Lab Part 1825.

Metric Nuts, Washers, and Spacers

M3 Nuts and Washers

Size	Lab Part #	Description
M3	Lab Part 1838	Zinc-Plated Steel Hex Nut, M3 x 0.5mm pitch, 5.5mm width, 2.4mm height
M3	Lab Part 1839	Medium-Strength Steel Nylon-Insert Locknut
M3	Lab Part 1836	18-8 stainless steel general purpose washer, 7mm outer diameter, 3.2mm inner diameter

Nylon spacer for M3 screws, 3.3mm inner diameter x 4mm length. Lab Part 6053.

Dowel Pins

Dowel pins come in wood, plastic, or metal. Wood pins are typically used to connect wooden parts. Plastic and metal are typically used as pivots or to precisely locate parts.

Wooden Dowel Pins

Size	Lab Part #	Description
1/4 x 1.5	Lab Part 1573	wooden dowel pin, 1/4 inch outer diameter, 1-1/2 inch length, fluted, chamfered ends
1/4 x 2.5	proposed	wooden dowel pin, 1/4 inch outer diameter, 2-1/2 inch length, fluted, chamfered ends
1/4 x 3.0	proposed	wooden dowel pin, 1/4 inch outer diameter, 3 inch length, fluted, chamfered ends
5/16 x 1.5	Lab Part 1575	wooden dowel pin, 5/16 inch outer diameter, 1-1/2 inch length, fluted, chamfered ends
3/8 x 1.5	Lab Part 1577	wooden dowel pin, 3/8 inch outer diameter, 1-1/2 inch length, fluted, chamfered ends

Sheet Metal and Wood Screws

These screws have sharp threads which can cut into an undersized wood hole.

Self-Tapping Screws

Size	Lab Part #	Description
#4 x 0.5	Lab Part 6057	screw, sheet metal, self-tapping, blunt, #4 x 1/2 inch length, Phillips No 1, pilot hole 0.086 inch (2.2 mm)