BIG-PLUS Dual Contact Spindle System
Simultaneous Taper & Flange Fit
BIG-PLUS is a dual contact spindle system where the shank contacts the spindle taper and the spindle face simultaneously, resulting in increased tool rigidity. 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
Minimized Deflection for Maximum Machining Accuracy & Superior Finish
With BIG-PLUS simultaneous contact, machining rigidity is greatly enhanced due to the larger contact diameter of the tool holder flange face. This larger face contact, combined with the taper contact, works together to resist deflection. With less deflection, greater machining accuracy and superior finish can be achieved.
Comparison of Deflection
Strict Gage Control
Cutting Conditions
Machine: 40 Taper (Horizontal Machining Center)
Cutter: Face Mill Ø5" (6 Cutting edges)
Work Material: A2017 Duralumin
Cutting Depth: .094"
Improvement of ATC Repeatability
The BIG-PLUS Spindle System assures the highest precision location of the tool holder in the spindle when using the ATC for loading tools as a result of the dual contact, which precisely positions the tool holder within 1 micron.
ATC Repeatability
Basic Concept
The BIG-PLUS Dual Contact 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 gage line. On the contrary, a BIG-PLUS tool holder is supported on the flange face, which brings remarkable improvement to rigidity.
Increased Contact Diameter (Example of BT50)
| Taper No. | Conventional | BIG-PLUS |
|---|---|---|
| CV50 | Ø2.750 | Ø3.875 |
| CV40 | Ø1.750 | Ø2.500 |
| BT30 | Ø1.250 | Ø1.811 |
Strict Gage Control
BIG-PLUS spindles produced by the licensed machine or spindle builders are strictly controlled in dimensions by the BIG original Master Gage. Only the BIG-PLUS trademarked tool holders can achieve the optimal performance fully and safely.
Gages for Machine Spindle
Not All Dual Contact Tooling is the Same!
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 gages nor dimensions and tolerances for the critical relationship of taper to the flange.
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Condition #1
Proper Fit
- Dual contact of taper and flange after clamping
Condition #2
Flange Contact Only
Limited or No Taper Contact
- Poor runout accuracy
- Severe chatter and vibration
- Spindle damage
Condition #3
Taper Contact Only
No Flange Contact
- Features of BIG-PLUS are voided
- Works same as taper-only contact tooling
BIG-PLUS Tooling Licensees
The following companies are licensed for production, sales, and use of the BIG-PLUS trademark:
BIG DAISHOWA INC
REGO-FIX
SHOWA TOOL CO, LTD
BIG KAISER PRECISION TOOLING LTD
SUMITOMO
SANDVIK COROMANT
YUKIWA SEIKO USA, INC
Only select BIG-PLUS tooling from licensed companies and ACCEPT NO IMITATIONS OR COPIES
All products will be clearly marked with the following indications on all parts:
BIG-PLUS® Spindle System
License BIG Daishowa Seiki
BIG-PLUS Spindle System Machine Builders
The BIG-PLUS Spindle System is offered by many of the world’s leading manufacturers of machining centers. Some of the machine and spindle builders who have produced BIG-PLUS spindles are as follows:
• Bold company names are North American licensed BIG-PLUS spindle rebuilders
Perfect Interchangeability
BIG-PLUS dual contact tool holders can be used on existing standard machine spindles. Existing standard tool holders can also be used on BIG-PLUS spindles. In this case, however, simultaneous contact cannot be attained. Although other simultaneous contact systems require exclusive new accessories, BIG-PLUS tooling uses existing accessories such as a tool presetter and tool holder fixture as it is based on a conventional steep taper shank. Further, it is not necessary to modify tool magazines and ATC devices of existing machines.
Existing Accessories Utilized
BIG-PLUS spindles have been adopted by licensed machine or spindle builders around the world under strictly controlled dimensions using BIG's Master Gage. In order to protect the spindle or prevent possible accident, only use tool holders with the BIG-PLUS trademark.