Since their creation in 1938, Helicoils have revolutionised both thread repair and thread use in softer materials. Having proven themselves billions of times throughout the modern world saving users both time and huge sums of money they are now manufactured by many companies to set international standards The most important step in creating a Helicoil hole is to select the correct drill. Below is a list of thread sizes and the drill required to make them.
Thread sizes M2 to M6
Thread size M2 x 0.40 Drill Diameter = 2.10mm
Thread size M2.2 x 0.45 Drill Diameter = 2.30mm
Thread size M2.5 x 0.45 Drill Diameter = 2.60mm
Thread size M3 x 0.50 Drill Diameter = 3.10mm
Thread size M3.5 x 0.60 Drill Diameter = 3.60mm
Thread size M4 x 0.70 Drill Diameter = 4.10mm
Thread size M4.5 x 0.75 Drill Diameter = 4.70mm
Thread size M5 x 0.80 Drill Diameter = 5.20mm
Thread size M6 x 1.00 Drill Diameter = 6.20mm
Thread sizes M7 to M16
Thread size M7 x 1.00 Drill Diameter = 7.20mm
Thread size M8 x 1.00 Drill Diameter = 8.20mm
Thread size M8 x 1.25 Drill Diameter = 8.30mm
Thread size M9 x 1.25 Drill Diameter = 9.30mm
Thread size M10 x 1.00 Drill Diameter = 10.30mm
Thread size M10 x 1.25 Drill Diameter = 10.30mm
Thread size M10 x 1.50 Drill Diameter = 10.30mm
Thread size M11 x 1.50 Drill Diameter = 11.30mm
Thread size M12 x 1.25 Drill Diameter = 12.30mm
Thread size M12 x 1.50 Drill Diameter = 12.40mm
Thread size M12 x 1.75 Drill Diameter = 12.40mm
Thread size M14 x 1.25 Drill Diameter = 14.30mm
Thread size M14 x 1.50 Drill Diameter = 14.30mm
Thread size M14 x 2.00 Drill Diameter = 14.30mm
Thread size M16 x 1.50 Drill Diameter = 16.25mm
Thread size M16 x 2.00 Drill Diameter = 16.50mm
Thread sizes M18 to M27
Thread size M18 x 1.50 Drill Diameter 1= 8.25mm
Thread size M18 x 2.00 Drill Diameter = 18.50mm
Thread size M18 x 2.50 Drill Diameter = 18.50mm
Thread size M20 x 1.50 Drill Diameter = 20.25mm
Thread size M20 x 2.00 Drill Diameter = 20.50mm
Thread size M20 x 2.50 Drill Diameter = 20.50mm
Thread size M22 x 1.50 Drill Diameter = 22.50mm
Thread size M22 x 2.00 Drill Diameter = 22.50mm
Thread size M22 x 2.50 Drill Diameter = 22.50mm
Thread size M24 x 1.50 Drill Diameter = 24.25mm
Thread size M24 x 2.00 Drill Diameter = 24.25mm
Thread size M24 x 3.00 Drill Diameter = 24.75mm
Thread sizes M27 to M42
Thread size M27 x 2.00 Drill Diameter = 27.50mm
Thread size M27 x 3.00 Drill Diameter = 27.50mm
Thread size M30 x 1.50 Drill Diameter = 30.50mm
Thread size M30 x 2.00 Drill Diameter = 30.50mm
Thread size M30 x 3.50 Drill Diameter = 30.50mm
Thread size M33 x 2.00 Drill Diameter = 33.50mm
Thread size M36 x 2.00 Drill Diameter = 36.50mm
Thread size M36 x 4.00 Drill Diameter = 36.50mm
Thread size M39 x 2.00 Drill Diameter = 39.50mm
Thread size M39 x 4.00 Drill Diameter = 39.50mm
Thread size M42 x 4.50 Drill Diameter = 43.00mm
Tips / Warnings
Always wear protection, cutting tools may shatter. Wear eye and hand protection.
Always clamp the piece you are drilling securely.
Always use a cutting oil, this will lubricate the drill / tap and prevent seizure and snapping of tools.
Ensure both your drill and Helicoil tap are square to the surface before and during the process.
