JKP and JKT Keyless High Precision Chucks
JKB and JKC CNC Keyless High Precision Chucks
The Jacobs high precision self-tightening chuck is ideal for high precision drilling. Maintaining your chuck will give you constant accuracy and longer life.
This precision drill chuck repair guide is also available as a pdf document.
Keyless Chuck Disassembly and Jaw Replacement
- Turn Jaws to fully close position.
- Clamp on chuck body in a vise with soft jaws to prevent scoring.(Fig 1.)
- Remove fixed ring by loosening the right hand set screw and slipping off.
- Clamp chuck in a vise with soft jaws and loosen front sleeve with pipe wrench by turning counter-clockwise.
Pipe wrench must have Teflon® inserts to prevent scoring. (Fig 2.)
- Remove jaws from lead screw.
- Remove jaw guide from ball retainer by pulling forward on jaw guide, this operation is to be performed only if parts are dirty.
- Remove lead screw from body and clean all parts in solvent and repack bearing with grease. Apply a light coat of oil over all parts prior to reassembly.
- Reassemble in reverse order. Note that the jaws are to be replaced as a complete set of 3, even though only one or two of the old jaws appear faulty
or worn. When tightening the front sleeve, clamp the chuck in a vise with soft jaws and tighten with pipe wrench.