RUKO STB-HSS-Gr.6-7/8-1-3/8 Step Drill Bit, HSS-G, 7/8-1-3/8 inch, 9 Steps

For sheet metal workers and electricians who need clean, burr-free holes in thin materials, this step drill bit from RUKO delivers precise, multi-diameter drilling in one tool. It is made from ground high-speed steel (HSS-G) and covers a range from 7/8 to 1-3/8 inches (22.2 to 35.0 mm) across 9 steps, each increasing by 1/8 inch (3.2 mm). The 3-surface shank prevents slipping in the chuck, and the 118° point angle ensures accurate starts. Suitable for sheet metal, non-ferrous metals, plastics, and stainless steel up to 1,000 N/mm², it is ideal for drilling, deburring, reaming, and chamfering.

Key specifications

• Material: HSS-G (high-speed steel, ground)
• Drill type: Step drill bit
• Diameter range: 7/8 - 1-3/8 inch (22.2 - 35.0 mm)
• Number of steps: 9
• Step increment: 1/8 inch (3.2 mm)
• Shank type: 3-surface shank (tri-flat)
• Shank diameter: 10 mm
• Overall length: 100 mm
• Maximum material thickness: 4 mm
• Point angle: 118°
• Flute type: Spiral flute
• Surface finish: Bright
• Standard: DIN 1412 C
• Direction of cut: Right-hand cut

Why choose it

The HSS-G construction provides high wear resistance and long tool life, while the ground finish ensures precise, clean holes. The step design eliminates the need for multiple drill bits, saving time and effort on the job.

Ideal use cases

• Drilling holes in sheet metal and thin plates
• Deburring and chamfering existing holes
• Enlarging holes in plastic or non-ferrous metals
• Working with stainless steel up to 1,000 N/mm²

Good to know

For optimal performance and tool life, use a suitable cutting fluid or coolant. The drill is designed for right-hand rotation and is compatible with standard drill chucks thanks to its 3-surface shank.