The Bernardo 4-jaw precision lathe chuck PO4 - 125 is a professional-grade lathe chuck, weighing 5 kg. Krollit has been an official Bernardo distributor since 2007.
- Chuck size A: 125
- B: 59.5 mm
- C: 4 mm
- d: 95 mm
- E: 35.5 mm
- F: 108 mm
Who uses the PO4 - 125 4-jaw precision chuck and for what
Machine shops and artisan turners use the PO4 - 125 4-jaw precision chuck as a clamping accessory on metal lathes, ensuring secure clamping and centering of the workpiece during turning, drilling, and grooving operations.
Its place in the Bernardo range
The Bernardo 4-jaw precision lathe chuck PO4 - 125 is part of the Bernardo lathe chuck range, distributed in Italy by Krollit since 2007. The Bernardo range includes models of various categories and performances: to choose the right machine for your use case, you can consult the Bernardo catalog on Krollit or contact customer support for selection assistance.
Krollit logistics and support
Shipping of spare parts and accessories from Krollit warehouse in 3-5 working days. Customer support in Italian available for technical documentation and compatibility verification with the reference machine. Krollit has been an official distributor since 2007.
Who is the PO4 - 125 4-jaw precision chuck for?
The PO4 - 125 4-jaw precision chuck is recommended for the following professional profiles:
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Machine shops and artisan turners: secure clamping of round or hexagonal workpieces on metal lathes for turning, drilling, and grooving operations.
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Users with a Bernardo lathe with a compatible flange: original replacement or upgrade for Bernardo range lathes (profi, hobby, etc.) with A2 mounting conforming to DIN 55029.
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Irregular or non-round workpieces: for asymmetrically centered workpieces, consider independent 4-jaw chucks or universal platforms.
Technical specifications
| B |
59.5 mm |
| C |
4 mm |
| d |
95 mm |
| E |
35.5 mm |
| F |
108 mm |
| G |
M8 |
| h |
51 mm |
| J |
20 mm |
| Chuck size A |
125 |
| Max. speed |
4800 rpm |
| Weight approx. |
5 kg |
Frequently Asked Questions
When to use a 4-jaw chuck?
Self-centering 4-jaw chucks are for square and 4-8 sided workpieces. The jaws move together with a single key.
The self-centering 4-jaw chuck (not independent jaws) clamps square or octagonal workpieces symmetrically. For off-center (eccentric, asymmetric) clamping, independent jaw chucks are needed.
What material is the chuck body made of?
The material is indicated in the title: steel (PO series) for maximum precision, cast iron (DK/PS series) for standard use.
The choice depends on the intensity of use and the required tolerance: steel for production and precision, cast iron for general use.
What workpieces is the Ø 125 mm diameter suitable for?
Suitable for small-medium workpieces (max Ø ~140 mm): bench lathes and artisan workshops.
The nominal diameter of the chuck indicates the maximum size of the body, not the maximum workable workpiece. The clamping capacity depends on the jaw opening (typically 60-70% of the nominal Ø).
How do I check compatibility with my lathe?
Check the type of mounting on the lathe spindle nose (Camlock D3-D15, or threaded M-mount) and the corresponding diameter.
On modern lathes, Camlock mounting is the most common. On older lathes, there may be a threaded (M-) or flanged mount. The lathe's technical documentation indicates the exact type.
How is chuck precision maintained?
Regular cleaning of the spiral mechanism, periodic lubrication with specific chuck grease, and concentricity check every 6 months with a dial indicator.
A jaw that moves with difficulty indicates chips or rust in the mechanism: disassemble, clean, and grease. Concentricity is checked by mounting a ground bar and measuring with a dial indicator: acceptable tolerance 0.03-0.1 mm depending on the model.
