I purchased another G3 chuck. I now have three. But this latest one seems really off center. There is a visible wobble when it is threaded up tight and when I cut a short piece of stock and flip it end for end, the turning is about a 32 nd of an inch out of round. I don't expect machinist precision, but this seems excessive. Are the jaws supposed to go on in a certain order.? or might something else be to blame? The threads seems clean and free of dirt and chips. I tried drilling a hole in a 1/4 inch disc held in the chuck. then flipped it over, and drilled again, definitely off. My other chucks do not visibly wobble this way.
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How precise should a chuck be threaded?
- Thread starter Perry Hilbert
- Start date
The jaws go on to the matching numbers on the slide, you should already know that. Theres been problems reported with bad inserts causing chuck runout. Check that part and be sure theres no obvious burrs or crossthreading present.
If you mark your original jaw sets on each chuck you could try swapping a set between chucks and you will quickly determine if it is the chuck or the jaws that have a problem.
When I bought a small Nova chuck, it was really wobbly. I called them, they requested a video to see it, and a new one was sent. Was told to throw away the faulty one.
I bought a G3 several yrs. ago. It was wobbly. Tried changing insert but that did not help. Took it back to Woodcraft and they gave me a new one that works fine. I use it a lot. Allyn
Some woodturners spend big dollars for an off-center chuck. 
Other than what has been said, When I changed/installed jaws I would always close them (snug) before final tightening. this will show that the jaws are closing properly. I would also try swapping the 1 and three position. Otherwise you may have a bad chuck. The Nova’s I use to own always had 0.003-0.005” runout, but nothing like 1/32”
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A couple of things other than jaws in the correct position and installing correctly as William described.
Did the insert come in a red Nova (Teknatool) box or was it in a baggie? One retailer sells inserts For Nova which they have made and these come in a baggie type packaging.
Remove the insert and with a q-tip damp with WD40 go around the inside of the chuck body. I have one which was way off an it did pick up a very small shard of metal from the machining.
Make sure the insert is well seated. The transfer of power is from the end of the insert to the mating surface inside the chuck body.
Some seem very tight and others not so much. After inserting I place the hex of the insert in a vice and try to tighten a little more; sometime it would move another 1/8 turn.
Did the insert come in a red Nova (Teknatool) box or was it in a baggie? One retailer sells inserts For Nova which they have made and these come in a baggie type packaging.
Remove the insert and with a q-tip damp with WD40 go around the inside of the chuck body. I have one which was way off an it did pick up a very small shard of metal from the machining.
Make sure the insert is well seated. The transfer of power is from the end of the insert to the mating surface inside the chuck body.
Some seem very tight and others not so much. After inserting I place the hex of the insert in a vice and try to tighten a little more; sometime it would move another 1/8 turn.
This is a threaded chuck, no insert. The chuck body visibly wobbles when the lathe is switched on. I used to have a run out measuring tool but lost it in a shop fire years ago.. I will try to rig up another to show the run out.
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Could be the wrong sized threads?
a 33x3.5m chuck will screw onto a 1 1/4 x 8 lathe. It will loose and won’t tighten properly.
It would wobble.
a 33x3.5m chuck will screw onto a 1 1/4 x 8 lathe. It will loose and won’t tighten properly.
It would wobble.
Installation of the chuck jaws out of order will not cause the chuck body to wobble.
As far as I know a direct thread G3 Nova chuck only comes in 1” 8 threads. This leaves a few possibilities.
1. Cross threaded this can happen to the best of us.
2. Threads on lathe spindle not 1”x 8 ( maybe 1”x12) or some such
3. Chuck defective.
Take a video of chuck running call Nova send them a copy and see what they say.
I have only had one of the many nova chucks that I have used not be accurate when remounting. The problem was one of the jaws was not seated in the slide. This was my fault seating the jaw fixed the problem. My G3 doesn’t wobble.
In your case with the chuck body wobbling, the cause lies else where.
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