Nova G3 Chuck Review: Jaws, Threads, and When to Upgrade

The Nova G3 is a four-jaw self-centering chuck made by Teknatool in New Zealand. It’s the chuck on every beginner’s “what do I need for bowl turning” list, and it earns that position: it’s well-made, widely stocked, the jaw system covers most of what a hobby turner needs, and it’s been in continuous production long enough that replacement parts and jaw sets are easy to find. If you have a midi lathe and you’re ready to turn bowls properly, the G3 is where most people start.

What a four-jaw chuck actually does

When you rough a bowl blank, you need to hold the wood. The first pass uses a faceplate screwed directly to the blank, or a screw chuck. But once you’ve turned the outside of the bowl to shape, you need to remount it to hollow the inside, and a faceplate won’t help you there.

A four-jaw chuck holds a tenon, a short cylindrical shoulder you turn on the foot of the bowl during the outside pass. Reverse the bowl, seat the tenon in the jaws, and you can hollow the inside without the screw hole that a faceplate would require. The self-centering design means all four jaws close simultaneously, so mounting is fast and repeatable.

The result is that you can remount and reposition bowl blanks in seconds. That changes the rhythm of turning: instead of planning each session around the bowl’s current mount, you just reverse, seat, and continue.

The G3’s spec in plain terms

The Nova G3 is machined steel with a black oxide finish. It grips using a dovetail jaw interface: each jaw has an angled inner face that locks onto a correspondingly angled tenon. This is more secure under lateral load than a straight-sided grip, which matters when you’re taking aggressive finishing cuts on a bowl that’s no longer perfectly round.

Key specs from teknatool.com (verified June 2026):

Thread selection. The insert version ships with one thread insert and accepts others, so you can adapt it to different lathes. The direct-thread version is milled for one spindle thread from the factory. If you own one lathe and know its spindle thread, direct thread is fine. If you’re not certain, or if you plan to buy a second lathe eventually, get the insert version and buy the appropriate thread insert separately.

For most American midi lathes (Jet JWL-1221VS, Rikon 70-220VSR, and a number of others) the spindle thread is 1 inch by 8 TPI. Verify your specific model before ordering. Powermatic full-size lathes also use a 1-inch-by-8-TPI spindle, though the matching chuck for those machines is the Pro-Tek, not the G3.

The jaw system: what fits and what it does

The G3’s real value is its jaw ecosystem. Most Nova jaw sets fit both the G3 and the Pro-Tek body. Here’s what each does:

50mm (2-inch) jaws, included with every G3. These grip tenons around 50mm in diameter, the standard size for bowl blanks in the 6-to-12-inch range. You turn the foot of the bowl to this diameter during the outside pass. Most turners use the 50mm jaws 80% of the time.

20mm jaws. For small work: pens, bottle stoppers, small goblets, thin spindles. If you plan to do any pen turning on the chuck rather than a mandrel, you’ll need the 20mm jaws. They close tight enough to grip the small tenon diameter that pen blanks require.

100mm jaws. For large-diameter blanks: platters, big natural-edge pieces. Less frequently needed at the hobby level, but essential if your midi lathe can handle larger stock and you want to work at the upper end of its capacity.

Cole jaws. These don’t grip a tenon. They hold a finished bowl by the outer rim, facing inward, so you can reverse-mount the bowl and turn the foot clean without the tenon. A must-have if you care about the base of your finished bowls. The foot is the last surface people touch when they pick up a bowl.

The Synergy bundle ships the chuck body with all four jaw sets as a kit. Buying it is almost always better value than buying the body and jaw sets separately, assuming you’ll eventually use all four types. The Cole jaws alone, bought separately, close a significant part of the price gap.

G3 vs Pro-Tek: the practical question

Both chucks use the same jaw sets and look nearly identical. The difference is the body.

The G3 body is built for lathes with swings up to about 14 to 16 inches. On a Jet JWL-1221VS turning a 10-inch bowl, the loads are within the G3’s design envelope. On a Powermatic 3520C turning a 16-inch wet-wood blank, the torques are higher, the blank is heavier, and Teknatool’s recommendation is the Pro-Tek, which has a heavier body built for full-size lathe loads.

For midi-lathe owners (JWL-1221VS, Rikon 70-220VSR, and comparable machines): the G3 is the correct choice. The Pro-Tek’s body mass is more than a midi lathe needs, and you’d be spending more for capacity that doesn’t match your machine. The G3 Synergy bundle handles bowl turning, pen and small spindle work, and reverse-turning without over-buying.

For full-size lathe owners (Powermatic 3520C, JET 1642, and similar): many turners run a G3 for smaller bowls under 12 inches and a Pro-Tek for large work. If budget is the constraint, a G3 on a full-size lathe is usable for smaller blanks. But if you’re buying one chuck for a full-size lathe, the Pro-Tek is the better starting point. The Powermatic 3520C review covers the chuck question from the lathe side.

Bottom line

The Nova G3 does one thing well and does it without drama: it holds bowl blanks securely while you hollow them, and the jaw system grows with you as your work diversifies. For a midi lathe, the G3 Synergy bundle is the buy. Get the insert version if your lathe’s spindle thread isn’t confirmed as 1-inch-by-8-TPI.

The G3 is available at Rockler and Woodcraft. If you’re fitting it to a Jet JWL-1221VS or Rikon 70-220VSR, the Jet JWL-1221VS review and the Jet vs Rikon comparison both confirm the spindle thread and cover what else those lathes include in the box.