Spindle Selection
What type of spindles are available on machine tools, and which is best for me? Over the past five to six decades, machine tool builders have developed many varied sizes and styles of machine tool tapers to hold the tool holders and cutting tools they want their machines to utilize. They look at multiple factors such as rigidity, RPM/Speed of spindle, size, and overall performance desired between machine control, accuracy of machine, and speed of table/head feed rate. Over the past three decades, the metal cutting industry has settled on five to six different spindle connections and machine tool builders design their equipment using any one of these taper technologies as it best suits their machine design.
NMTB
Old technology mainly used on manual equipment and large boring mills where automatic tool changes are not needed..
CAT40/CAT50
The ANSI/ASME B5.50 was designed in the early 1980’s for use with automatic tool-changing systems in machines. Read More
BT30/40/50
MAS403 spindle connection. Originally a standard design on all Japanese designed and produced machine tools. Read More
BT & CAT Face Contact
Face Contact designs, which were developed by Daishowa Seiki Co. in 1994 under US Patent 5352073, took the benefits of the MAS 403 and ANSI/ASME designs but removed the “weakness” from higher RPM machining by utilizing a face contact between the flange of the tool holder and the spindle face of the machine tool spindle. This additional contact surface allows more rigidity because of the larger “footprint” the spindle face contact offers. This large diameter of contacts increases the “leverage point” between spindle taper, spindle face, tool taper, and tool flange face. Excellent design where long-length tools and/or large diameter tools benefit from additional tool/taper contact for accuracy and rigidity. While this design is like the BT-MAS and CAT-ANSI, interchanging styles of tapers in a face contact spindle is not recommended. Accutek follows the expired US Patent 5352073 to maintain the integrity of the design as our AccuPlus™ product.
HSK – DIN 69893 A, C, E, and F styles
HSK means “hollow shank” and uses a drawbar that pulls the taper into the machine using internal gripping vs. the external drawbar gripping that steep taper designs use with a retention knob. While this is a spindle connection for metal working machines like the steep taper designs, this design allows for much higher spindle RPM machining because of the spindle/drawbar, and connection design. The “low profile design” and balanced orientation slots allows for a much higher spindle RPM without the spindle opening “bell-mouthing” seen in the steep taper designs. HSK also uses the face contact to increase tool holder rigidity for radial loads. HSK does require a change in “machine programming culture”. With ANSI and MAS403 designs, heavy radial loads at lower spindle RPMs is the normal practice. With the HSK shank such heavy radial loads are handled differently by increasing spindle RPM, lighter chip loads on cutting tools, and an overall increase in machining metal removal rates.Read More
ISO26623-1 CAPTO®
In the mid-1990s the new machine technology was the Multi-Tasking machining center or the Mill-Turn machining centers. This new machining technology required a spindle connection that not only could rotate for rotational machining applications like milling, drilling, tapping, etc. but also maintain a static or stationary position for turning – thus the multi-tasking or mill-turn names. Rotational tool machining presents a specific set or forces that static or stationary turning does not present. Conversely, static or stationary turning presents machining forces not seen in rotation tooling applications. Read More
ISO26622-1 KM®
Determining your spindle connection for your next machine tool purchase depends on your comfort level with new spindle technology, need for increased machining capabilities, and type of work you plan to process through the new machine. While there are advantages with Steep Taper designs as well as HSK Taper designs, you will need to match those advantages to your specific machining needs. Read More
