TOP-TOOL 320mm / 12-Inch 4-Jaw Independent Lathe Chuck, Plain Back, Clamping Range 20–320 mm (0.79–12.60 in), T-Key
TOP-TOOL 320mm / 12-Inch 4-Jaw Independent Lathe Chuck, Plain Back, Clamping Range 20–320 mm (0.79–12.60 in), T-Key
Professional 320mm / 12-Inch 4-Jaw Independent Lathe Chuck (Plain Back)
The TOP-TOOL four-jaw independent chuck holds round, square, rectangular, and irregular parts by adjusting each jaw separately. Unlike a self-centering scroll chuck, you can dial in concentricity with a dial indicator or intentionally offset the work for boring or turning eccentric features. This listing is the plain back configuration—machine an adapter plate to match D1, D2, and the bolt pattern (adapter not included).
Envelope reference: combined internal-jaw and external-jaw ranges cover approximately 20–320 mm (0.79–12.60 in) depending on jaw orientation and setup.
Materials
| Component | Material |
|---|---|
| Body | High-grade gray cast iron (HT200 / HT300 class, series dependent) |
| Jaws | Hardened steel |
|
|
Hardened steel |
Clamping ranges
Internal jaws (A–A1): 20–176 mm — typical OD gripping with jaws in the standard orientation.
External jaws (B–B1): 100–320 mm — clamping larger diameters / reverse-jaw style holding per factory chart.
Use the jaw positions and factory instructions that match your operation; the overall span above is a quick reference only.
Key Features
- Independent jaws: Four separate adjustments for square, round, or off-center work.
- Plain back (D1/D2): Recess diameter D1 = 140 mm, depth h = 6 mm; bolt circle D2 = 165 mm; 4× M16.
- Through hole D3: 95 mm for bar work (confirm against your bar stock).
- Heights: H = 134 mm overall, H1 = 90 mm body thickness reference.
- T-Key included for jaw adjustment.
Technical Specifications
Dimensions from factory K72-series plain-back table; clamping from K72 clamping-range chart.
| Parameter | Value |
|---|---|
| Chuck diameter (D) | 320 mm (12.60 in) |
| D1 (mounting recess diameter) | 140 mm |
| h (recess depth) | 6 mm |
| D2 (bolt circle diameter) | 165 mm |
| D3 (through hole) | 95 mm |
| H (overall height) | 134 mm |
| H1 (body thickness) | 90 mm |
| Internal jaws (A–A1) | 20–176 mm |
| External jaws (B–B1) | 100–320 mm |
| Mounting | 4× M16 |
| Net weight | 39.6 kg |
Applications
- Shafts, rings, and rounds where you want manual control of runout.
- Square or rectangular billets; weldments and castings with uneven OD.
- Light eccentric turning when the machine and setup allow.
Compatibility
Lathe swing must clear diameter D and fully extended jaws. Build or purchase an adapter that matches D1, D2, and the listed bolt pattern.
Maintenance
Keep jaw slides clean; lubricate per factory practice with chuck grease or light oil suitable for slideways.
Safety
Never leave the chuck key engaged; respect safe RPM for size and balance.
Styled With
Materials
HT300 AISI1045 AISI 5140
Included Accessories
Chuck Key (T-Type) / Bolts
Details
Backplate not included.