JACOBS
Frequently asked questions
Common questions about JACOBS from 3G Electric.
What is the difference between a Jacobs Taper (JT) and a Morse Taper (MT) in JACOBS drill chucks?
Jacobs Taper (JT) is a proprietary taper system used specifically for mounting JACOBS drill chucks onto arbor sleeves or directly onto machine spindles. JT tapers are numbered (e.g., JT0, JT2, JT6) and have a specific angle and length. Morse Taper (MT) is a standardized taper used in machine tool spindles, such as drill presses and lathes. JACOBS produces arbors that convert an MT spindle to a JT chuck mount, allowing a JACOBS chuck to be used on a machine with an MT spindle. For example, the JACOBS arbor MPN 7318N adapts MT3 to JT6.
How do I select the correct JACOBS drill chuck key for my chuck model?
JACOBS drill chuck keys are model-specific and are identified by the key type (e.g., K0, K2, K3C) and pilot diameter. The key type corresponds to the chuck's tightening mechanism. For example, the K3C key (MPN JCM3653P) is designed for JACOBS chucks that use a 5/16 in pilot. To select the correct key, match the key model number to the chuck's specifications, which are listed in the product datasheet. Using the wrong key can damage the chuck or cause slippage.
Are JACOBS stainless steel drill chucks suitable for use in food processing or pharmaceutical environments?
Yes, JACOBS stainless steel drill chucks, such as the corrosion-resistant model MPN JCM6624Z, are designed for environments where moisture, chemicals, or washdowns are present. The stainless steel construction resists rust and corrosion, making them suitable for food processing, pharmaceutical, and marine applications. These chucks are taper-mount (JT0) and have a ball-bearing design for smooth operation. However, they are not certified for direct food contact; they are intended for toolholding in machinery used in those industries.
What is the maximum runout tolerance for JACOBS high-precision keyless drill chucks?
JACOBS high-precision keyless drill chucks, such as the ball-bearing models MPN 31415 (MT4, 1/8 in to 5/8 in capacity) and MPN 31407D (MT2, 25/64 in capacity), are manufactured to a runout tolerance of 0.0016 in (0.04 mm) or better at the chuck nose. This precision is achieved through hardened and ground components and ball-bearing construction. For exact specifications, refer to the product datasheet, as tolerances may vary by model and capacity range.
Can I use a JACOBS Morse taper sleeve to adapt a drill chuck to a different spindle size?
Yes, JACOBS Morse taper sleeves, such as the MT1 to MT4 sleeve (MPN 30427DN), allow you to adapt a smaller inner taper to a larger outer taper. For example, a drill chuck with an MT1 shank can be mounted into a spindle with an MT4 bore using this sleeve. The sleeve provides a secure fit and maintains concentricity. Ensure that the sleeve length and taper angles match the spindle and tool shank specifications to avoid slippage.
Does 3G Electric supply JACOBS products?
Yes — 3G Electric (S) Pte. Ltd. supplies JACOBS products. We stock the JACOBS catalog and supply genuine factory-original products with full manufacturer warranty and technical support.















































