Super High-Speed Live Center (BHS Family) Overview
A comprehensive guide to the super-high-speed live center family — covering the BHS/BHSC standard type, BHSL30 extended 30° type, and BHSL30A extended A type — including features, specifications, carbide-tipped points, selection guidance, and applications.
Overview
▲ Product appearance (POINTTECH catalog)
A live center is a precision tailstock tool that supports one end of a workpiece while rotating together with it. Because an internal bearing carries the rotation, a live center avoids the friction and heat build-up of a dead (fixed) center, making it suitable for high-speed work. The BHS-series super-high-speed live centers push this principle to its limit, simultaneously achieving rotational speeds up to 15,000 rpm and run-out (TIR) accuracy within 0.002 mm (0.0001").
The family is offered in three types to suit different working conditions: the standard BHS (with carbide-tipped variant BHSC); the extended 30° BHSL30, whose shaft extension improves tool clearance and machining flexibility; and the further-extended A type BHSL30A. All types use a labyrinth seal to keep coolant out and a heat-treated spindle and body (HRc 60 ± 2) for rigidity and long service life.
Key Features
- Accuracy guaranteed to 0.002 mm TIR (0.0001") — suited to precision grinding and finishing
- Excellent for CNC, grinder and high-precision, high-speed machining
- High RPM — up to 15,000 rpm (model-dependent ceiling)
- Heat-treated point to HRc 60 ± 2 for wear resistance and form retention
- Labyrinth seal for coolant deflection and super-high-speed operation
- Heat-treated body for extra strength, rigidity and long life
- Drain hole located on the bottom side to expel ingressed fluid
- Carbide-tipped point available — point hardness HRa 90 ± 5
- BHSL30 / BHSL30A shaft-extension types improve tool clearance and machining flexibility
To maintain accuracy at super-high speeds, the Morse taper (MT) sleeve and tailstock bore must be clean and concentric. The listed Max RPM and workpiece weight are not concurrent maxima — permissible load decreases as rotational speed rises (see the RPM-vs-load relationship under Selection Guide). The 0.002 mm run-out figure assumes a new, correctly seated unit; impact or overload can damage the bearing and degrade accuracy.
Specifications (BHS / BHSC Standard Type)
MODEL (Carbide) | MT | A | C | L | Workpiece Weight | Max R.P.M | Weight | Max Run-Out |
|---|---|---|---|---|---|---|---|---|
041002 (042002) | 2 | 50 | 68 | 148 | 360 | 15,000 | 1.5 | 0.002 |
041003 (042003) | 3 | 50 | 85 | 165 | 360 | 15,000 | 1.8 | 0.002 |
041004 (042004) | 4 | 70 | 108 | 220 | 560 | 12,000 | 2.2 | 0.002 |
041005 (042005) | 5 | 70 | 136 | 248 | 560 | 12,000 | 5.2 | 0.002 |
Unit: mm, kg. Model numbers in parentheses are the carbide-tipped (BHSC) variant. Refer to the catalog drawing for detail dimensions B, D, E, F and G.
Specifications (BHSL30 Extended 30° Type)
MODEL (Carbide) | MT | A | C | L | Workpiece Weight | Max R.P.M | Weight | Max Run-Out |
|---|---|---|---|---|---|---|---|---|
043002 (044002) | 2 | 50 | 68 | 160 | 280 | 15,000 | 1.8 | 0.002 |
043003 (044003) | 3 | 50 | 85 | 174 | 280 | 15,000 | 1.8 | 0.002 |
043004 (044004) | 4 | 70 | 108 | 236 | 450 | 12,000 | 2.2 | 0.002 |
043005 (044005) | 5 | 70 | 136 | 264 | 450 | 12,000 | 5.2 | 0.002 |
Unit: mm, kg. Model numbers in parentheses are the carbide-tipped (BHSL30C) variant.
Specifications (BHSL30A Extended A Type)
MODEL (Carbide) | MT | A | C | K | L | Workpiece Weight | Max R.P.M | Max Run-Out |
|---|---|---|---|---|---|---|---|---|
045002 (046002) | 2 | 50 | 68 | 19 | 167 | 250 | 15,000 | 0.002 |
045003 (046003) | 3 | 50 | 85 | 19 | 184 | 250 | 15,000 | 0.002 |
045004 (046004) | 4 | 70 | 108 | 23.5 | 246.5 | 390 | 12,000 | 0.002 |
045005 (046005) | 5 | 70 | 136 | 23.5 | 281 | 390 | 12,000 | 0.002 |
Unit: mm, kg. Model numbers in parentheses are the carbide-tipped (BHSL30AC) variant. Body weights are 1.8 kg for MT2/3, 2.2 kg for MT4 and 5.2 kg for MT5.
Carbide-Tipped Point
In addition to the standard steel point, each type is available with a carbide-tipped point hardened to HRa 90 ± 5. Carbide tips hold their form far longer on abrasive castings, heat-treated stock and hard materials, or during long continuous runs, preserving run-out accuracy over time. Carbide-tip part numbers by Morse taper are listed below.
Type | MT2 | MT3 | MT4 | MT5 |
|---|---|---|---|---|
BHSC-TYPE | 042002 | 042003 | 042004 | 042005 |
BHSL30C-TYPE | 044002 | 044003 | 044004 | 044005 |
BHSL30AC-TYPE | 046002 | 046003 | 046004 | 046005 |
Selection Guide
First match the model to your tailstock bore Morse taper (MT2–MT5). Then evaluate workpiece weight and target speed together. The catalog technical-data curves show that both permissible workpiece weight and axial load fall as speed rises — for example, the 4,5BHS (MT4/MT5) carries the highest load at low speed but drops sharply as it approaches 12,000 rpm. Do not size a center assuming maximum speed and maximum weight at the same time.
- Standard high-speed, high-precision work → BHS / BHSC (standard type)
- Need reduced tool/chuck interference and longer reach → BHSL30 (30° extended)
- Tight-clearance work needing extra extension and a slender nose → BHSL30A (A extended)
- Abrasive materials or long continuous runs → choose the carbide-tipped variant of the relevant type
- MT2 / MT3 = 15,000 rpm ceiling; MT4 / MT5 = 12,000 rpm ceiling
The extended types (BHSL30 / 30A) have a longer overall length (L) and a slimmer nose for better access, but their permissible workpiece weight at a given speed is set lower than the standard type. Choose them when access and interference avoidance matter more than maximum rigidity.
Applications
- High-speed OD and face turning on CNC lathes
- High-precision between-centers grinding on cylindrical grinders
- End support of long rotating bodies such as shafts, rollers and spindles
- Machining of hard, wear-prone materials (carbide-tipped variant)
- Multi-axis and combined machining with frequent tool interference (extended BHSL30 / 30A)