Value-Turn Live Center (BB / BBL30) Overview
A comprehensive reference for the economical Value-Turn live center in standard (BB) and extended 30° (BBL30) types, covering features, dimensions, carbide-tipped points, and selection guidance for light-to-medium lathe work.
Overview
▲ Product appearance (POINTTECH catalog)
The Value-Turn Live Center is a rotating (live) center that mounts in the tailstock of a conventional or CNC lathe and supports the workpiece center hole while turning with it. Unlike a dead center, which stays fixed while the work rotates against it, a live center carries the rotation on internal bearings, eliminating the friction, heat, and wear that would otherwise scorch a fixed point at speed. The Value-Turn family is an economy line focused on light-to-medium-duty work and is offered in two types: the standard BB and the extended 30° BBL30, whose elongated point geometry further reduces tool interference.
Both models use a slim body diameter (B) to minimize interference with the cutting tool, leaving generous clearance for tool approach even on facing operations or small-diameter work. The rear bearing is sealed to protect the internal assembly from coolant and chips, and the point is heat-treated to HRc 60±2 to preserve accuracy through repeated use. Every model guarantees run-out (TIR) within 0.003 mm (0.0001").
Key Features
- Accuracy guaranteed to 0.003 mm TIR (0.0001") — suited to precision OD and facing work
- Excellent for light-medium-duty work on conventional lathe machines
- Slim body diameter improves tool clearance
- Heat-treated point to HRc 60±2 for wear resistance and long life
- Rear bearing is sealed, protecting the assembly from coolant and chips
- Carbide-tipped point available (BBC / BBL30C types)
- Carbide point hardness: BB to HRa 90±5; BBL30 to HRa 90±5
- BBL30: extended 30° point geometry for enhanced tool accessibility
Specifications
Dimensions are in mm and weights in kg. Numbers in parentheses are the model numbers for the carbide-tipped versions (BBC / BBL30C). A is the body diameter, B the nose diameter, and L the overall length.
MODEL (Carbide) | MT | A | B | L | Workpiece Weight | Max. Axial Load | Max. RPM | Weight | Max. Run-Out |
|---|---|---|---|---|---|---|---|---|---|
BB 121003 (122003) | 3 | 44.5 | 25 | 161.5 | 400 | 400 | 5,000 | 1 | 0.003 |
BB 121004 (122004) | 4 | 44.5 | 25 | 184.5 | 400 | 400 | 5,000 | 1.2 | 0.003 |
BB 121005 (122005) | 5 | 63 | 28 | 229 | 500 | 500 | 4,000 | 2.8 | 0.003 |
BBL30 123003 (124003) | 3 | 44.5 | 22 | 165 | 320 | 320 | 5,000 | 1 | 0.003 |
BBL30 123004 (124004) | 4 | 44.5 | 22 | 188 | 320 | 320 | 5,000 | 1.2 | 0.003 |
BBL30 123005 (124005) | 5 | 63 | 28 | 238 | 400 | 400 | 4,000 | 3 | 0.003 |
Workpiece Weight and Max. RPM are independent maximums. As the technical-data curves in the catalog show, the permissible workpiece weight and axial load both fall as RPM rises — do not assume the tabulated maxima can be met simultaneously. To maintain the HRc 60±2 point hardness and 0.003 mm run-out, never exceed the stated RPM limit.
Carbide-Tipped Point
In place of the standard steel point, a carbide-tipped point can be specified. The carbide point offers far higher wear resistance, greatly reducing point wear on rough center holes (as on forged or cast stock), in abrasive cutting environments, and during long continuous runs. Carbide point hardness is HRa 90±5.
MT | BBC (Standard Carbide) | BBL30C (Extended 30° Carbide) |
|---|---|---|
MT3 | 122003 | 124003 |
MT4 | 122004 | 124004 |
MT5 | 122005 | 124005 |
Selection Guide
- Morse taper match: select the model to match your lathe tailstock taper (MT3 / MT4 / MT5).
- Standard (BB) vs extended (BBL30): use BB for general work; choose the 30°-extended BBL30 where the cut runs close to the part end or tool interference is severe.
- Load and speed: cross-check workpiece weight and running speed against the technical-data curves and choose with margin; for heavier work or heavier cuts step up to MT5.
- Point spec: a standard steel point suffices for general steel work, but specify a carbide tip (BBC / BBL30C) for rough center holes, continuous runs, or high-wear environments.
- Accuracy class: this is an economy line for light-to-medium duty. For very high speed, higher precision, or heavy interrupted cutting, consider higher-tier families (e.g. high-precision BNH, heavy-cut TN).
Applications
The Value-Turn family serves general OD turning, facing, and grinding support across light-to-medium-duty work on conventional and CNC lathes. Its slim body makes it especially favorable for slender shaft-type parts, short shafts, and components with frequent facing operations. It fits high-mix low-volume shops as well as training and maintenance lathes where accuracy-per-cost matters, and the carbide-tip option extends its reach to the rough center holes typical of cast and forged stock.