Holder Performance
Alan Miller
consider the spindle speed required. If a hydraulic chuck exceeds its rated RPMs, fluid is pulled away from the holder’s internal gripping gland, causing loss of clamping force. But when used within its recommended operating range, a hydraulic tool holder offers superior runout and repeatability. On average, a good shrink-fit holder has about .0003" runout, while a hydraulic chuck offers .0001" or better. 7. Don’t overlook the tool’s effects on holder performance The cutting tool affects holding ability more than most machinists and engineers realize: a. Polished shanks reduce friction. b. Oil and coolants reduce gripping power. c. Cutter shank roundness is often assumed to be close enough to perfect to ignore, but in reality a 25 millionths tolerance is necessary for high-speed performance.
the supply chain and/or sales process. The easiest way to figure if an interface is BIG-PLUS is to place a standard tool into the spindle and see how much of a gap there is between the tool holder flange face and spindle face. Without BIG-PLUS, the standard gap should be visible, or about .12". If it is BIG-PLUS, the gap is half of this amount, or only .06". These values change depending on 30 taper, 40 taper or 50 taper sizes, but the gap is visibly less than usual. 10. Use positive offsets during holder setup It may be how it’s traditionally been done, but touching off holder assemblies in each machine to establish negative tool offsets based on the zero- point surface—the vise, machine table, workpiece, etc.—is not the most efficient process. We think the choice is pretty clear: adapting machines to a single presetter so they can receive positive gage lengths is superior to using all types of machine-specific negative offsets. This is a change to “the way things have always been done” that can be met with some resistance, but in the grand scheme of things, it’s a relatively small and simple step that makes life much easier. It’s essentially a relatively low-cost opportunity to introduce more standardization of holder setup to the shop floor. Holders are the bridge between the machine and the part. That’s a lot of pressure—literally and figuratively. It’s important to select, care for and use holders carefully from the day they are purchased until they’re tossed into the recycling bin. From collet chucks to coolant inducers, BIG KAISER is North America’s source for standard-bearing tool holders that guarantees high performance.
8. Not all dual-contact tooling is the same
Anyone in the market for BIG-PLUS ‘dual-contact tooling’ should consider this simple statement: Only a licensed supplier of BIG-PLUS has master gages that are traceable to the BIG grand master gages and have the dimensions and tolerances provided to make holders right. Everyone else is guessing and using a sample BIG-PLUS tool holder as their own master gage—a practice that any quality expert will advise against. Look for the marking: “BIG-PLUS Spindle System-License BIG DAISHOWA SEIKI.” 9. You may have a BIG-PLUS spindle and not even know it You’d be surprised how often we hear from our certified regrinders or engineers in the field about folks that didn’t realize their machine had a BIG-PLUS spindle—the message can get lost in
CONTRIBUTOR AlanMiller is the EngineeringManager & Product Manager BIG at BIG KAISER Email: alan.miller@us.bigkaiser.com
11
Powered by FlippingBook