KM vs. Capto tooling systems

[Mechineer]

I have spoken to numerous tool salesmen about KM and Capto style tooling systems but I would like other opinions of people who have used them. Which one is most rigid?

 

[EdDanzer]

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.

 

[Mechineer]

I am partial to stick tooling as well but I need to cut our setup times. I am looking into quick change chuck jaws and a solution to decrease our barfeeder setup times. Our setup times on our mill-turn lathe range from 1.5 hrs to 3.5 hrs. I have considered using bar stock diameters in increments of 1/4" and turn off the excess material to reduce the # of times the barfeeder must be adjusted for new material but I am not sure this is feasible until I do some more research. Any suggestions are welcome.

 

[EdDanzer]

We had a Wasino LJ63M mill turn for several years and used KM50 and Komet ABS drills to reduce setup time. We had several sets of nuts for chuck jaws so the operator could be preparing for the next part number to be machined. All jaws were sets for specific part diameter, and several had steps of a standard depth (1/4”). A few were for a specific part number. Loosening 2 bolt and switching jaws is only a few minutes slower than the fastest quick change chuck and the jaws are less expensive. We end up with about 10 sets of chuck jaws per machine. We have a Forkhardt quick change chuck and find it to be slower to work with in some cases because we have not bought extra master jaws (very expensive). Changing diameter is very little faster since you must back the masters out before shifting position.
Capto might be a better choice if *** the tools are available. Capto or KM will be ok if you choose a size larger than the largest boring bar you use. We should have used KM63.
What size of machine are you using?
How many tools do you have to change per part number and what type of tools are they?
What type of parts and quantity are you doing?