Hydraulic Hard Jaws
This series of 3-step hydraulic hard jaws is precision machined from 20CrMnTi alloy steel with a fine grinding finish for superior surface quality and reduced run-out. Through full hardened treatment, these hard jaws for 3-jaw hydraulic chucks deliver stable clamping force, high concentricity, and repeatable accuracy even under heavy-duty cutting conditions.
- Ranging from 5″ to 24″ (5″, 6″, 8″, 10″, 12″, 15″, 18″, 21″, 24″), fully compatible with most standard hydraulic chucks.
- Through-hole (hollow) and solid versions are available for 12″ & 15″ chuck jaws.
- Non-standard customization supported – contact us with your drawing or specifications.
Product Feature
- Centered clamping for high concentricity.
- Precision one‑shot milling ensures stable equidistance and structural integrity.
- Made of 20CrMn / 40CrMnTi alloy, hardened to HRC 60‑65 after quenching.
- Accuracy is within 0.05 mm.
- Ready to use with simple installation. No extra jaw trimming is required.
- One set of hard jaws supports both external gripping and internal expanding, improving work efficiency while reducing overall costs.
- 3 jaws per set.


Product Specification
Three‑step Version Hard Jaws


| L | W | H | W1 | D1 | P | H1 | H2 | H3 | L1 | L2 | L3 | Mounting | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 5-inch Chuck | 53 | 23 | 28 | 10 | 14 | 1.5×60° | 13 | 10 | 29 | 24 | M8 | ||
| 6-inch Chuck | 68 | 31 | 48 | 12 | 20 | 1.5×60° | 24 | 12 | 12 | 21 | 18 | 29 | M10 |
| 8-inch Chuck | 87 | 35 | 51 | 14 | 25 | 1.5×60° | 27 | 12 | 12 | 29 | 18 | 40 | M12 |
| 10-inch Chuck | 101 | 40 | 54 | 16 | 30 | 1.5×60° | 28 | 13 | 13 | 46 | 18 | 37 | M12 |
| 12-inch Hollow | 108 | 50 | 67 | 21 | 30 | 1.5×60° | 35 | 16 | 16 | 49 | 20 | 39 | M16 |
| 12-inch Solid | 108 | 50 | 67 | 18 | 30 | 1.5×60° | 35 | 16 | 16 | 49 | 20 | 39 | M16 |
| 15-inch Hollow | 143 | 62 | 86 | 22 | 43 | 1.5×60° | 46 | 20 | 20 | 55 | 38 | 50 | M20 |
| 15-inch Solid | 143 | 62 | 86 | 25 | 43 | 1.5×60° | 46 | 20 | 20 | 55 | 38 | 50 | M20 |
- L: Total length
- W: Total width
- H: Total height
- W1: Groove width
- D1: Center distance
- P: Tooth pitch
- L1: 1st step length
- L2: 2nd step length
- L3: 3rd step length
- H1: 1st step height
- H2: 2nd step height
- H3: 3rd step height
One‑step Version Hard Jaws
| L | W | H | W1 | D1 | P | H1 | H2 | L1 | L2 | Mounting | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 5″ | 53 | 23 | 28 | 10 | 14 | 1.5×60° | 13 | 10 | 29 | 24 | M8 |
| 6″ | 67.5 | 31 | 38 | 12 | 20 | 1.5×60° | 24 | 12 | 40 | 27.5 | M10 |
| 21″/24″ | 159.5 | 80 | 90 | 50 | 3.0×60° | 50 | 40 | 97.5 | 62 | M20 |

(Minimum clamping diameter: 7mm)
Groove width: 14mm,
Center distance: 25mm,
Tooth pitch: 1.5×60°,
Mounting screw: M12

4-jaw Version Hard Jaws

- Slot width: 14mm
- 1 set contains 4 jaws
- Mounting screw: M12
- Center distance: 25mm
- Tooth pitch: 1.5×60°

- Slot width: 16mm
- 1 set = 4 jaws
- Mounting screw: M12
- Center distance: 30mm
- Tooth pitch: 1.5×60°







