Hydraulic expansion technology for tool holders has many benefits, such as minimal run-out, repeat accuracy, flexible clamping range, easy handling and vibration dampening. In this month’s blog we will discuss the characteristics and many benefits of these tool holders.

What Are Hydraulic Tool Holders?

Hydraulic tool holders are perfect for machining operations that entail high accuracy, such as drilling, reaming, and end milling, as well as operations using specialty tools such as carbide form and PCD tipping tooling. These chucks are the ideal tool holder for high precision machining in medical, aerospace, automotive, and die & mold.

Very versatile, the hydraulic tool holders have a large variety of tool diameters to fit common shanks in both metric and inch as a direct diameter clamp, or the use of sleeves to utilize many variations with one holder. They are also available for simultaneous fit systems and all other major interfaces that you may require with your machine.

A Hydraulic Tool Holder uses a reservoir of oil to equalize clamping pressure around the tool. When you place the tool in the holder and turn the screw inwards, it increases the oil pressure, causing an expansion of the sleeve to grip the tool shank.

In the picture above, you can see the anatomy of the hydraulic tool holder, highlighting the following:

1: Clamping screw that will increase the oil pressure to clamp the expanding sleeve.

3: Expansion sleeve and chamber system also know as the hydraulic bladder that will apply a tremendous amount of pressure holding the tool in place.

Benefits of Hydraulic Tool Holders

• Vibration Dampening: oil in the bladder reduces the harmonics when rotating at higher RPM’s resulting in less chatter. This also leads to better surface quality and prevents micro-blowouts on the tool’s cutting edge.
• Repeat Accuracy: best run-out accuracy and a repeatability of less than 0.003 mm (0.00012”) are achieved, which converts directly into cutter tool life increase, since the chip load on each cutting flute is more uniform – if one of the cutter’s teeth is carrying a heavier load than the others, it will cause premature failure of the cutter, therefore shorter tool life.
• Easy Handling and Tool Change: clamping the tool can be done in a fast and secure way with the help of a hex key. Improving the tool changing process reduces unproductive set-up and machine down times.
• Flexible Clamping Range: when using intermediate sleeves, hydraulic tool holders can typically cover a clamping range from 3 to 32mm (1/8” to 1-1/4”) diameter.
• Compatibility: hydraulic tool holders can be combined with all common machine tool interfaces.

Our preferred supplier partners that offer a comprehensive range of hydraulic tool holders include Schunk and Sandvik Coromant.

Hydraulic chucks are a powerful addition to any machine shop looking to improve their precision machining capability.

For more information about the benefits of Hydraulic Tool Holders contact us.