Overview

The Autobox K72 series 4 jaw independent chuck gives you individual control over each jaw — unlike a self-centering chuck where all jaws move at once, each jaw on this chuck adjusts separately via its own screw. That means you can grip square stock, rectangular bar, castings, forgings, and irregular shapes, or deliberately offset a round workpiece for eccentric turning. Available in 3" (80mm), 4" (100mm), and 5" (125mm) diameters to fit mini lathes and bench lathes commonly used by hobbyist machinists.

Available Options

• 3" (80mm) — K72-80: suited for smaller mini lathes and light workpieces, $52.95
• 4" (100mm) — K72-100: most common size for 7" swing mini lathes, $62.95
• 5" (125mm) — K72-125: suited for larger mini lathes and bench lathes with adequate swing clearance, $74.95

Key Features

• Individual jaw adjustment: each of the four jaws moves independently via a dedicated adjustment screw — no scroll plate, no linked movement
• K72 series construction: hardened steel jaws and body; K72 series is the industry-standard designation for 4-jaw independent lathe chucks
• Grips any cross-section: round, square, rectangular, hex, octagonal, or irregular — any shape that fits within the jaw travel range
• Eccentric and off-center turning: deliberately position a round workpiece off-center for crankshaft-style operations, offset bores, and cam lobes
• Chuck key included: T-handle chuck wrench included for adjusting each jaw
• Three diameter options: 80mm (3"), 100mm (4"), and 125mm (5") to match your lathe's swing and your workpiece size

Specifications

Compatibility

This chuck mounts to the headstock spindle nose of your lathe. Most mini lathes use an MT3 headstock taper with a threaded spindle nose — an adapter backplate (sold separately) is required to mount this chuck to your spindle. Verify your spindle nose thread and diameter before ordering. Confirmed compatible machines:

• Sieg C2 / SC2 / C3 (MT3 headstock, verify spindle thread for backplate sizing)
• Harbor Freight 7x10 #93212 (MT3 headstock)
• Harbor Freight 7x12 #44142 (MT3 headstock)
• Grizzly G0765 7x14 (MT3 headstock)
• Grizzly G8688 7x12 (MT3 headstock)
• LittleMachineShop HiTorque 7x16 (MT3 headstock)
• Autobox 7x14 / 8x16 (MT3 headstock)

Not sure if this fits your spindle? Email us a photo of your spindle nose — we will confirm before you order.

What's in the Box

• 1x K72 series 4-jaw independent chuck (your selected size)
• 1x T-handle chuck key / chuck wrench

Note: adapter backplate is NOT included. Most mini lathe installations require a backplate matched to your spindle nose thread and diameter. See our compatible backplates or contact us with your lathe model.

Frequently Asked Questions

Q: What is the difference between a 4-jaw independent chuck and a 4-jaw self-centering chuck?
A: A 4-jaw self-centering chuck moves all jaws together, so round and square stock centers quickly. A 4-jaw independent chuck adjusts each jaw separately, so it can hold irregular shapes and offset round work for eccentric turning, but setup takes longer.

Q: When should I choose a 4-jaw independent chuck instead of a 3-jaw or 4-jaw self-centering chuck?
A: Choose a 4-jaw independent chuck when you need to hold square, rectangular, hex, or irregular stock, perform eccentric turning, re-center a part for a second operation, or grip castings and forgings. For routine round stock, a self-centering chuck is faster.

Q: Do I need an adapter backplate to mount this chuck on my mini lathe?
A: Yes, in most cases. This chuck has a flat back with mounting holes and does not thread directly onto the spindle. You need a backplate matched to your spindle nose thread and register size. If unsure, send us your lathe model.

Q: Which size should I choose — 3", 4", or 5"?
A: Choose based on your lathe’s swing and workpiece size. The 4" K72-100 is the most common for 7x10 and 7x14 mini lathes. The 3" K72-80 suits lighter work. The 5" K72-125 needs enough swing clearance, so confirm fit before ordering.