-From Onsrud Cutter Website: www.onsrud.com

Climb and Conventional cutting merely describe the way in which the cutter moves around the part in respect to its direction of rotation. In regards to a right-hand rotation spindle (the most common type),moving around a finished part counter-clockwise would be considered Conventional Cutting while a clockwise part path would be Climb Cutting. The terminology will be reversed if the spindle is of left-hand rotation or a pocket or hole is being cut out of the finished part.

In most cases, conventional cutting provides the best edge provided the right tool geometry to cut a specific material has been selected. This applies mainly to man-made board products. If you are cutting solid wood where multidirectional grain patterns have to be considered, it is often necessary to employ climb cutting thereby limiting the chip the tool can remove at one time and reducing splintering. In CNC routing with right hand rotation tooling, climb cutting occurs as the perimeter of the workpiece is routed in a clockwise direction. Routing the same workpiece in a counter clockwise direction represents conventional cutting. The whole process is reversed when making internal cuts on the part. When workpiece finish is substandard, check the scrap as a comparison. If the scrap finish is better, change the direction of the tool.

The other factors when considering Climb or Conventional Cutting is the aggressiveness of the cutter and part hold down. Climb Cutting is a much more aggressive means of cutting and can chatter or move small parts that are not fixtured well. In most cases soft chips that are difficult to extract from the cut are also more likely to weld to the climb cut side rather than the conventional cut side. The best method of approach for most new materials is to run sample parts with both methods of cutting at the same feeds and speeds and make the determination from there.