1/4"-28 Machine Screws

1/4-28 Machine Screws in all available lengths, grades, materials, and finishes. This collection covers every 1/4-28 option in stock — use the filters to narrow by length, grade, material, and finish.

1/4-28 Thread Specifications

• Nominal diameter: 0.25"
• Threads per inch: 28
• Tap drill (75% thread): #3 (0.213")
• Clearance hole (close fit): 17/64" (0.266")
• Clearance hole (free fit): 9/32" (0.281")

To thread a 1/4-28 hole, drill with a #3 (0.213") tap drill for a standard 75% thread. For a clearance hole that the 1/4-28 screw passes through, use 17/64" (0.266") for a close fit or 9/32" (0.281") for a free fit. Pair with a matching 1/4-28 nut or tapped hole.

Orders before 12 PM ET ship same day.