Steep taper JIS (MAS 403) BT30/BT40/BT50
The spindle interface JIS B 6339 as the traditional interface for milling spindles distinguishes itself through it robust design. Its field of application ranges from fine machining to heavy duty roughing. The tool holder is pulled in the milling spindle with the help of an additional pull stud. The centering takes place via the taper contact. Therefore, the JIS B 6339 interface is primarily suitable for applications with a spindle speed of up to 12,000 rpm.
Technical specifications JIS B 6339
Steep taper BT30
- Tool holders case-hardened 60 – 2 HRC
- Tensile strength in the core at least 950 N/mm2
- Taper in tolerance quality AT3
- Angle of cone: 8° 17'50'' +5''
- Without bore for data chip
- Form ADB: interior coolant supply through centre (form AD) and through the collar (form B)
| BT30 | D1 | D2 | D3 | D4 | L1 | L2 | L3 | T | B1 | B2 |
| [mm] | 31,75 | 12,5 | 46 | 42 | 48,4 | 22 | 13,6 | M12 | 16,1 | 16,3 |
Steep taper BT40
- Tool holders case-hardened 60 – 2 HRC
- Tensile strength in the core at least 950 N/mm2
- Taper in tolerance quality AT3
- Angle of cone: 8° 17'50'' +5''
- Without bore for data chip
- Form ADB: interior coolant supply through centre (form AD) and through the collar (form B)
| BT40 | D1 | D2 | D3 | D4 | L1 | L2 | L3 | T | B1 | B2 |
| [mm] | 44,45 | 17 | 63 | 59 | 65,4 | 27 | 16,6 | M16 | 16,1 | 22,6 |
Steep taper BT50
- Tool holders case-hardened 60 – 2 HRC
- Tensile strength in the core at least 950 N/mm2
- Taper in tolerance quality AT3
- Angle of cone: 8° 17'50'' +4,5''
- Without bore for data chip
- Form ADB: interior coolant supply through centre (form AD) and through the collar (form B)
| BT50 | D1 | D2 | D3 | D4 | L1 | L2 | L3 | T | B1 | B2 |
| [mm] | 69,85 | 25 | 100 | 95,5 | 101,8 | 38 | 23,2 | M24 | 25,7 | 35,4 |
Coolant supply JIS B 6339
According to JIS B 6339, 3 possibilities of inner coolant supply are available:
- Form A: No inner coolant supply
- Form AD: Central coolant supply through retention knob. A retention knob with centralized bore is required.
- Form B: Lateral coolant supply via the collar. A sealed retention knob is required.
Haimer clamping devices with taper according to DIN 69871 are performed in form ADB unless otherwise noted.
Form ADB means: The clamping devices are equipped with bores for form AD as well as for form B. Unless otherwise stipulated, the tool holders are delivered in form AD. The bores at the collar for form B are then sealed with plastic-dowels and secured with lock screws.
For changing to form B, the bores at the collar must be opened by unscrewing the lock screw halfway. Extraction of screws together with thedowels by using pliers.
The bores also can be sealed again. A conversion kit consisting of dowels and lock screws is available.
Attention: Each dowel for single use only!
