V-COIL STI Twist Drill – Thread Repair
V-COIL STI Twist Drill – Precision for Thread Repair
The V-COIL STI Twist Drill is an essential tool for enlarging core holes of damaged or worn threads.
When a thread is damaged due to wear, material fatigue, or improper handling, the STI twist drill provides the perfect solution:
it creates the precise hole diameter required for the installation of thread inserts.
Made of high-quality HSS-G (ground high-speed steel), the drill offers a long tool life, precise cutting, and excellent surface quality.
With sizes ranging from 2.1 mm to 13.0 mm, it covers a wide field of application and is ideal for
unalloyed and low alloyed steels as well as other machinable materials up to 900 N/mm².
The STI twist drill is available individually, in complete V-COIL thread repair kits, and as part of larger assortments.
This makes it a flexible solution both for workshops and mobile use.
The STI twist drill is used wherever threads need to be repaired or reinforced. Typical applications include:
- Enlarging core holes of worn or damaged internal threads
- Preparing holes for V-COIL thread inserts
- Use in workshops, mechanical engineering, automotive repair and maintenance
- Available in sizes from 2.1 mm to 13.0 mm
- Suitable for machinable materials up to 900 N/mm² (e.g. steel, aluminum, cast materials)
- Preparation: Secure the workpiece, prepare the workspace, and wear safety goggles. Identify the damaged thread.
- Insert the drill: Mount the STI twist drill in a drilling machine or drill press. Apply cutting oil.
- Enlarge the core hole: Drill out the damaged thread evenly and enlarge the hole to the correct size.
- Remove chips: Pause regularly, remove chips, and reapply cutting oil.
- Check: Inspect the borehole to ensure it is ready for the thread insert.
Q1: Why do I need a special STI twist drill?
A1: Standard drills often don’t provide the exact tolerances required. STI drills are specifically optimized for thread insert applications.
Q2: Can the drill be used for blind holes?
A2: Yes, depending on the thread insert type, it can be used for both through and blind holes.
Q3: Do I have to use cutting oil?
A3: Yes, cutting oil reduces tool wear and ensures better drilling quality.
Q4: Is it suitable for hardened steels?
A4: No, it is designed for materials up to 900 N/mm². For hardened steels, special tools are required.
Q5: Is the STI twist drill available in kits?
A5: Yes, it is sold individually, in repair kits, and as part of assortments for various thread sizes.
Do you have questions about the V-COIL STI Twist Drill or want advice on complete repair kits?
Contact us via our contact form.
