Four-Jaw Chucks
Four-jaw chucks are a very nice workholding option for woodturning projects that can't be held between centers (e.g. bowls).
They do not automatically center a workpiece like three-jaw chucks you may know from metal turning, but have other advantages to work especially well with wood.
The chucks come with different jaw sets (Spannbacken) for different diameters. You don't use the "pointy" base jaws directly because they dent the wood! Instead, in the first step a recess or tenon (Zapfen) with the exact jaw diameter (and often a dovetail profile) is turned with other workholding options and the workpiece is then flipped around to be held by the chuck.
For Jaw Chuck with both chuck sets
Four-Jaw Chuck without any chucks (do not use it like this)
Four-Jaw Chuck holding a workpiece
Precision
The holding force is best when the jaw diameter (and shape) matches the workpiece precisely. Reportedly, it can be improved further by tightening both chuck screws, not just one. HolzWerken 99
We could make laser cut templates for the various jaw sets!
Turning green wood can be an exception to this rule: keeping in mind shrinkage, you may want to oversize your tenon during the first round of rough turning so you can cut it to the proper size when you finish the piece. [1]
Available Chucks
The chucks are screwed onto a wood lathe's spindle screw, so they are somewhat machine specific based on the thread.
| Chuck | Name | Thread | Lathes | Jaw Sets |
|---|---|---|---|---|
| For Jaw Chuck | SuperNove² Woodturning Chuck | Tyme Avon | Small and large one |
Helpful Videos
- wortheffort: Woodturning Chucks, Jaws, Tenons and Recesses - detailed explanations (36 min) of hardware and strategies to maintain the strength of the wood
- Mike Waldt: Woodturning - How to Hold Work Securely in a Chuck - short demonstration (10 min) of proper tenon/recess diameters
- Woodworker's Journal: Scroll Chuck Basics - rough overview (4 min) of the chuck's operation
- Maschinenhandel Meyer: Gefährlich und ungenau - welches Drechselfutter eignet sich zum Drechseln...und welches nicht! - (DE) Kaufberatung mit vielen wichtigen allgemein gültigen Punkten
