High-Speed Premium Live Center (BNH · BNHL30 · BNHL30A) Complete Guide
Covers the roller-bearing High-Speed Premium Live Center in standard (BNH) and extended (BNHL30, BNHL30A) forms, with 0.002mm TIR accuracy, up to 6,000 rpm, HRc60±2 heat treatment, and the full dimension and carbide-tip data.
Overview
▲ Product appearance (POINTTECH catalog)
A live center is a tailstock tool that supports a workpiece by its center hole while rotating together with the work. Unlike a dead (fixed) center, the internal bearing absorbs the rotation, eliminating friction heat and seizure and allowing stable support at high speed. This family uses a roller-bearing construction and a heat-treated body to guarantee run-out within 0.002mm (0.0001") TIR and rotation up to 6,000 rpm, placing it in the precision class.
The family comprises the standard BNH (carbide-tipped variant: BNHC), the 30° extended BNHL30, and the extended A-type BNHL30A. The BNHL30 and BNHL30A are shaft-extension types with an elongated nose that reduces tool interference and improves machining flexibility in tight working areas.
Key Features
- Accuracy guaranteed to 0.002mm TIR (0.0001")
- Excellent for CNC, grinder and high-speed precision machining
- High RPM (up to 6,000)
- Heat-treated point to HRc 60 ± 2
- Based on roller bearings for superior performance
- Anti-friction seal for coolant deflectors and high speed
- Heat-treated body for extra strength, rigidity and long life
- Carbide point available (carbide point to HRa 90 ± 5)
- BNHL30 / BNHL30A: shaft-extension type for reduced tool interference and machining flexibility
The 0.002mm TIR accuracy and up to 6,000 rpm are guaranteed under correct mounting and alignment. The listed Max. R.P.M and Workpiece Weight are not simultaneous limits: permissible load decreases as speed rises (see Selection Guide). Always operate within the load envelope that corresponds to your actual rpm.
Specifications
MODEL (Carbide) | MT | A | B | C | D | L | Workpiece Weight | Max. R.P.M | Max. Run Out |
|---|---|---|---|---|---|---|---|---|---|
BNH / 031003 (032003) | 3 | 50 | 22 | 85 | 51.5 | 162.5 | 750 | 6,000 | 0.002 |
BNH / 031004 (032004) | 4 | 66 | 32 | 108 | 64 | 213 | 1,500 | 6,000 | 0.002 |
BNH / 031005 (032005) | 5 | 80 | 40 | 136 | 70 | 247 | 2,600 | 5,000 | 0.002 |
BNHL30 / 033003 (034003) | 3 | 50 | 22 | 85 | 51.5 | 171.5 | 600 | 6,000 | 0.002 |
BNHL30 / 033004 (034004) | 4 | 66 | 32 | 108 | 64 | 225 | 1,100 | 6,000 | 0.002 |
BNHL30 / 033005 (034005) | 5 | 80 | 40 | 136 | 70 | 271 | 2,000 | 5,000 | 0.002 |
BNHL30A / 035003 (036003) | 3 | 50 | 22 | 85 | 51.5 | 186.5 | 500 | 6,000 | 0.002 |
BNHL30A / 035004 (036004) | 4 | 66 | 32 | 108 | 64 | 235.5 | 900 | 6,000 | 0.002 |
BNHL30A / 035005 (036005) | 5 | 80 | 40 | 136 | 70 | 286 | 1,700 | 5,000 | 0.002 |
Unit: mm, kg. Part numbers in parentheses are the carbide-tipped model numbers. Refer to the catalog drawing for the full A–G (and K) dimensions. MT is the Morse taper shank, which must match the tailstock sleeve.
Carbide-Tipped Point
The standard point is steel heat-treated to HRc 60±2. For abrasive high-speed or long-running operations and high-hardness materials, the carbide point (HRa 90±5) is recommended. The carbide tip offers far higher wear resistance, reducing wear and seizure at the center-hole contact and preserving long-term accuracy.
Family | Type | MT3 | MT4 | MT5 |
|---|---|---|---|---|
BNH | BNHC-TYPE | 032003 | 032004 | 032005 |
BNHL30 | BNHL30C-TYPE | 034003 | 034004 | 034005 |
BNHL30A | BNHL30AC-TYPE | 036003 | 036004 | 036005 |
Selection Guide
First match the shank to your tailstock sleeve Morse taper (MT3/MT4/MT5). Then check workpiece weight against the running speed. As the catalog technical data (rpm vs. workpiece weight / axial load curves) shows, permissible load falls as speed rises. The 'Workpiece Weight' figures are therefore low-speed maxima; at high speed the part must be run at a lower load.
- BNH (standard): the most versatile choice for general CNC turning and grinding. Shortest overall length (L) and highest permissible workpiece weight for a given MT.
- BNHL30 (30° extended): suited to work needing an elongated nose to clear tool interference; slightly lower permissible weight than BNH at the same MT.
- BNHL30A (extended A-type): the slimmest, most extended nose for maximum access in tight areas, but the most conservative permissible workpiece weight.
- Abrasive / high-hardness materials or long unattended runs: select the carbide-tipped variant (BNHC / BNHL30C / BNHL30AC).
Applications
Used for high-speed, high-precision between-centers support on CNC lathes and cylindrical grinders, for shaft-type automotive, aerospace and die/mold components, and on unattended long-run machining lines. It is particularly suited to precision OD and surface work demanding 0.002mm-class run-out, and to shoulder/groove features where tool access is difficult and an extended nose is required.