The Workhorse Unilock 138 Series Chuck Can Now Do Even More

We hear all the time how so many of our customers rely on the Unilock 138 series round workholding chuck for its mid-size diameter and adaptability to custom fixture designs. That versatility has made it BIG Kaiser’s best-selling round workholding chuck. Considering its popularity, the minds at Innotool—makers of Unilock—have come up with new ways to take advantage of the chuck’s quick and easy setup and loading, self-guided top-side mounting, and the strength and consistency of zero-point clamping in even more applications.

We here at BIG Kaiser are excited to introduce the ESM 138 Turbo and the ERGO 138. These new versions share virtually all of the same fundamental body dimensions—diameter, bolt hole pattern, open port orientation, knob type, etc.—making them direct swaps for the original ESM 138. But they each bring a little something extra to the table.

What’s Special about the ESM 138 Turbo
This improved version of the ESM 138 chuck can double the holding power of the standard chuck by tapping into its turbo capability. A new closed-back construction makes it possible to more than double the spring-only clamping force, up to roughly 3,520 lbs, by simply connecting an air source to either the 1/8G turbo port on the OD, or the underside o-ring port. The sealed back also protects the chuck’s piston from contaminants, reducing maintenance while improving consistency.

Another new design feature appearing in the ESM 138 Turbo is slotted pin actuation. The dual-angled slot allows for faster and stronger transfer of clamping force upon closing, as well as a quicker, even release of the knob.

What’s Special about the ERGO 138
The ERGO 138 also has a sealed back, protecting the internal mechanics from contamination and making it turbo-capable. In another effort to help maintain clean operations, the back cover has an air blast port which cleans the knob upon entry. By connecting an air source, operators can clean the chuck and knob before locking it, ensuring firm and consistent positioning during loading/unloading and preserving the equipment. It’s ideal for fine-particle materials like cast iron.

The ERGO 138 gives you more workable area a more secure connection than the standard chuck, and all without sacrificing any functionality or rigidity. Its body height measures in at 28mm, that’s 11mm shorter than the standard ESM 138. Rectangular clamping pins are substituted for standard round pins and now lock the knob more securely with a knee-type lock—reducing the chance of slippage. The inner contact ring has been expanded to Ø80mm, offering a larger contact surface area than the ESM 138’s Ø60mm.

As mentioned earlier, the new features add improved characteristics, but do not affect the ability to exchange with original ESM 138 chucks on a 1-for-1 basis.

Need help selecting the right valve system for your Unilock chuck(s)? View our newest “How-To” video here.