Sherline
Sherline 4-Jaw Chuck for Pocket NC
Independent 4-jaw chuck workholding for the Pocket NC. Sherline-made, Pocket NC trunnion adapter included. Hold round, square, or irregular stock — including off-centre and asymmetric workpieces — with the precision and clamping force a 3-jaw or vise can't match.
Why a 4-jaw chuck
A 3-jaw self-centering chuck only grips concentric round stock. A vise only grips parallel-sided stock. The 4-jaw independent chuck holds anything you can pull into the centre with four screws — round, square, hex, rectangular, cast forms, and intentionally off-axis features.
For Pocket NC owners, this opens up:
- Watch components & jewellery — eccentric features, off-centre bores, small cylindrical stock
- Cast parts — clamp on the rough exterior while machining the inside
- Long round stock — turn-style holding for cylindrical workpieces longer than vise jaws can grip
- Off-axis features — clamp a part deliberately off-centre to machine bolt holes or sockets at an offset
- Hexagonal & square stock — direct gripping without soft-jaw machining
Specifications
| Parameter | Value |
|---|---|
| Manufacturer | Sherline Products Inc. (USA) |
| Type | Independent 4-jaw chuck |
| Jaw action | Independent (each jaw adjusted separately for asymmetric holds) |
| Jaws | Reversible — internal & external gripping |
| Trunnion mount | Pocket NC adapter plate included |
| Compatibility | Pocket NC V2-10 · V2-50 CHB · V2-50 CHK |
| Material | Hardened steel chuck body, hardened reversible jaws |
| Centering tolerance | Each jaw independently set with a dial indicator (±0.01 mm achievable) |
| Made in | USA |
What's in the box
- Sherline 4-jaw independent chuck
- Set of 4 reversible jaws (already installed)
- Pocket NC trunnion adapter plate
- Chuck key
- 4× M5 mounting screws
- Setup guide
Setup on the Pocket NC
- Remove your existing vise or fixture from the trunnion table
- Bolt the Pocket NC adapter plate to the trunnion using the 4× M5 cap screws
- Mount the chuck onto the adapter — register pin aligns the chuck centre to the trunnion centre
- Tighten the chuck retainer
- Re-set your G54 origin (trunnion centre is now the chuck face)
- For dial-indicated truing: rotate the trunnion to expose each jaw, adjust each jaw screw until the indicator reads within target tolerance
4-jaw vs LANG vise vs standard Pocket NC vise
| Holding need | Best fit |
|---|---|
| Parallel-sided block stock | Standard Pocket NC vise (included with machine) |
| Repeatable production setups | LANG Self-Centering Vise Kit |
| Round stock — concentric holding | 3-jaw self-centering (separate accessory) |
| Round / square / irregular / off-axis | This 4-jaw chuck |
| Watch / jewellery / micro work | This 4-jaw chuck (with soft jaws) |
FAQ
Will it fit the V2-50 too?
Yes — same trunnion mounting pattern across V2-10 and V2-50 (CHB and CHK). The adapter plate is universal.
Can I use soft jaws?
Yes. The four installed jaws are reversible hard jaws; Sherline soft jaws (aluminium, brass) are sold separately for delicate finished surfaces.
Will it interfere with B-axis rotation?
Within the standard Pocket NC trunnion clearance envelope (the chuck height + workpiece must fit under the spindle at full B/A rotation). For tall workpieces, validate clearance in the simulator at sim.pentamachine.com before cutting.
Lead time?
In stock at Köln — same-day shipment for orders before 14:00 CET. Sherline manufacturing in California; restock from factory is 2–3 weeks if we're out.
Returns?
14-day return for private buyers under EU Widerrufsrecht. Commercial returns subject to our AGB. See Returns & Refunds.
Pair with
- Annual Maintenance Contract — keep the machine calibrated for the precision the chuck unlocks
- Owner training course — module on workholding strategy
- Forum thread: Fixture and workholding ideas — community-curated setups
Request CAD files, postprocessors, drawings or tooling library
Pick what you need and we'll email it back. Replies within one working day.
