Product Help

Here we have some commonly asked questions with our answers or demos. These Quick help links give you some answers but you can still speak to one of our friendly and knowledgeable staff who can give you the answer there and then. Call 0115 978 5454 Monday to Friday 8.00am - 5.00pm


What size drill bit should I use with my self-tapper?

 Self-tapping screw drill chart


What size drill bit should I use with a Thread Tap?

Tap Chart


 Bolt Head, thread length and pitch Chart

Diameter (d)PitchLength of threaded portion* (b)Head Depth (k)Across Flats (s)
M4 0.7mm 14mm 2.8mm 7mm
M5 0.8mm 16mm 3.5mm 8mm
M6 1.0mm 18mm 4mm 10mm
M7 1.0mm 20mm 4.8mm 11mm
M8 1.25mm 22mm 5.3mm 13mm
M10 1.5mm 26mm 6.4mm 17mm
M12 1.75mm 30mm 7.5mm 19mm
M14 2mm 14mm 8.8mm 22mm
M16 2mm 38mm 10mm 24mm
M18 2.5mm 42mm 11.5mm 27mm
M20 2.5mm 46mm 12.5mm 30mm
M22 2.5mm 50mm 14mm 32mm
M24 3.0mm 54mm 15mm 36mm
M27 3.0mm 54mm 15mm 41mm
M30 3.5mm 66mm 18.7mm 46mm
M33 3.5mm 72mm 21mm 50mm
M36 4mm 78mm 22.5mm 55mm
M39 4mm 84mm 25mm 60mm
M42 4.5mm 90mm 26mm 65mm
M45 4.5mm 96mm 28mm 70mm
M48 5mm 102mm 30mm 75mm