For precise work, a low TIR may be important. For multiple setups, quick change capability may be essential for high productivity. Tool retention force may be the weak link in a tough job. This chart shows the relative overall performance ratio for a typical 3⁄4-inch shank cutting tool using the most common solutions:
|TIR||S/R Ratio||Clamp Range||Gripping Power||Pullout security||High Speed||Damping||Handling|
|FACE MILL HOLDER||001’||1.7-2.7||None||Weak||High||Low||Low||Excellent|
|SHRINK FIT HOLDER||0001’||1.7-2.7||None||Strong||Moderate||Excellent||Low||Moderate|
Cutting tool attributes for good holding
Does the cutting tool affect holding ability? More than many machinists and engineers realize. The amount of available shank for gripping is a significant factor.
Polished shanks reduce friction, as does the cleanliness of both the shank and toolholder. Oil and coolants reduce gripping power. Cutter shank roundness is often assumed to be close enough to perfect to ignore, but in reality a 25.
Similarly, ISO h6 tolerance of the tool’s shank dia meter is important, which for smaller tools can mean 0-6 micron repeatability. Most shops lack the ability to check low micron diameter tolerances, so a good tool supplier is essential here.