Back in 1996 we did stiffness tests with quick change tool joints compared to a 1 ½” boring bar. Tested were new KM 50, Capto 50, ABS 50 boring bars and clamping units, and a 1 ½” steel shank boring bar. The test was done in a new Hitachi HT40G turning center. A 2 ½” diameter part was chucked with 4” of stick out, a load cell was connected to the chucked part and the boring bars. The load cell was located the same distance from the joint face on the quick change tools, and from the sleeve on the stick tool. A .0001” indicator was mounted on the turret disk near the tool block and located a specific distance from the load cell point to measure deflection at given loads.
The results confirmed our gut feelings. The most rigid tool was the 1 ½” boring bar, its deflection was linear, for each 10 lbs of load applied the deflection measurement was the same. Our max load was equal to 200 lbs. of tool pressure in the X direction.
Each of the quick change tools had problems, the ABS 50 was the next most linear in deflection after an initial preload was applied, we saw ±.0005” movement with less than 50 lbs load applied initially.
The Capto 50 did not have any low load problems but the deflection became greater as the load increased in a non linear way.
The KM50 was the least stiff and had the greatest non linear deflection.
With that said, we use Komet ABS drills, some KM tooling and would consider Capto for some jobs. Our preference is stick tools. We do small 1-20 pc. lot CNC turning and milling. Even though quick change tooling can save some in setup time, the lack of rigidity can increase machining times, scrap, and tool wear to the point of costing more than changing stick tools.