GRAFF long drill bit for metal 4 mm is made of high speed steel. Drill bits of this type are effective for operations in hard-to-reach places or when drilling thick materials. This is when quality meets the price. These drill bits have accuracy class A1 thanks to their polished cutting edge.
135 degree angle at the apex and cross sharpening provide excellent metal drilling without predrilling. Extra long drill bits are made according to DIN 338 and excellent for working in industrial enterprises, small workshops and subsidiary farms.
Drill size: – 4x78x119 mm where 4 mm is diameter, 78 mm is working length, 119 mm is total length.
The recommended number of revolutions for a drill bit with 4 mm diameter is 2870 rpm. Please note that this very drilling speed is for non-alloy steel. When processing other metals, speeds will differ.