RUKO Step Drill Bit HSS Size 4, 3/16 inch - 7/8 inch (4.8 - 22.2 mm), 10 Steps, DIN 1412 C

With a drilling range from 3/16" to 7/8" (4.8 mm to 22.2 mm) across 10 steps, this RUKO step drill bit in high-speed steel (HSS) delivers precise, burr-free holes in sheet metal, non-ferrous metals, and plastics up to 4 mm thick.

Overview

The RUKO STB-HSS-Gr.4-3/16-7/8 is a size 4 step drill bit manufactured to DIN 1412 C. Its spiral flute and cross-ground point with 118° point angle ensure self-centering and clean cutting. The bright, uncoated surface reduces friction and heat buildup.

What stands out

• 10 clearly marked imperial steps: 3/16", 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 3/4", 7/8"
• Metric equivalent range: 4.8 mm to 22.2 mm
• Deburrs while drilling, eliminating secondary operations
• Cylindrical shank with 10 mm diameter fits standard drill chucks
• Overall length 75 mm for good reach in tight spaces

Technical details

• Material: HSS (High-Speed Steel)
• Standard: DIN 1412 C
• Drill bit type: Step drill bit
• Size designation: Size 4
• Number of steps: 10
• Step increments: 3/16", 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 3/4", 7/8"
• Shank type: Cylindrical
• Shank diameter: 10 mm
• Flute type: Spiral flute
• Point geometry: Cross-ground point
• Point angle: 118°
• Surface treatment: Bright (uncoated)
• Maximum material thickness: 4 mm
• Overall length: 75 mm

Our verdict

A versatile step drill for professionals and serious DIYers who need clean, accurate holes in thin materials without changing bits.