These Industrial and Scientific Cutting Tools failed to live up to expectations .While the cobalt material seemed promising for a stronger drill bit the spiral cutting design led to frequent slipping and wobbling during use. The price point may be attractive, but the lack of precision and efficiency makes it an overall unsatisfactory purchase for serious industrial drilling..
Pros
Cobalt material for added strength
Cons
Spiral cutting design causes slipping and wobbling
Good drills. 3.3mm Used for 4m tap pilot hole Works like a charm. The beats bite immediately. Recommend a cutting oil such as Tap Magic or Sulfur Dark.