THE BIG-PLUS SPINDLE SYSTEM IS AN ORIGINAL DEVELOPMENT OF BIG DAISHOWA SEIKI CO., LTD.
BIG-PLUS — The World’s Most Rigid Dual Contact Spindle System Adopted by more than 100 machine tool builders for over the past 20 years, thousands of machines and tens of thousands of BIG-PLUS tool holders are in operation today. Due to the popularity of BIG-PLUS, many tooling companies, without a proper license agreement, gauges, or manufacturing specifications & tolerances are offering dual contact tooling. The achievement of dual contact is only possible by strict control of flange face location to taper gauge line.
S P I N D L E S Y S T E M DUA L CON T AC T Simultaneous Taper & Flange Fit
BIG-PLUS surpasses all other spindle concepts while offering interchangeability with existing machines and tool holders. • Improved surface finish & dimensional accuracy • Extended tool life • Prevention of fretting corrosion caused by heavy cutting • Improvement of ATC repeatability • Elimination of Z-axial movement at high speeds • Improved roundness of boring operations
Basic Concept The BIG-PLUS Spindle System is based on the most current available standards in ASME B5.50, JIS B6339 and DIN 69871. A conventional steep taper tool holder is supported on a reference diameter called the gauge line. On the contrary, a BIG-PLUS tool holder is supported on the flange face, which brings remarkable improvement to rigidity.
Distance Between the Taper Gauge Line and Tool Flange is the Critical Dimension for BIG-PLUS
Taper Gauge Line
BIG-PLUS Dual Contact Works on a Very Small Amount of Spindle Elastic Deformation Taper contact before clamping is very important and therefore the dimension and tolerance for the flange face is extremely critical to achieving dual contact. There are 3 possible outcomes depending on the actual tool holder specification. The Current Market Contains Many Suppliers of Dual Contact Tooling Who Are NOT Licensed for BIG-PLUS Without the license, they have neither the exclusive gauges nor dimensions and tolerances for the critical relationship of taper to flange. We acquired many of these tools from all regions of the world and inspected them with our gauges.
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