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I'm soon to upgrade from a 10x18 lathe to a Nova 1624. Question is should I upgrade to the Super Nova2 chuck or would my G3 work just fine. Not wanting to push my limits until I get used to the lathe. Any others I should be looking at? Thanks for the info!!
The G3 will serve you well and you can move up to the larger chuck when ready to do so. Make sure you have the right thread size.
It isn’t the lathe size that would be the deciding factor, but what you turn that is important. The manual for the G3 states it is ok for lathes up to 14”, so that would be a starting guideline.
John makes the crucial point -- it's what you are turning which ought to determine chuck size. I use a G3 for turning spindles on an American Beauty. For large bowls or platters I use a Stronghold or SN2.
I have a couple of Nova chucks and Oneway chucks. My favorite is the Vicmarcs in The VM 100 and the VM 120. I can really get a hard bite with T-handles instead of the worm jaws and handle. The again I have arthritis, need all the help I can get.
With a properly sized tenon there is no need to reef down on the piece. I use the 2" jaws a lot and depending on the lathe I'm using I grab a chuck that has either a 1" X 8 or 1 1/4" X 8 and that could be a G3 or a SN II or any one of four other brands I use. I have never had a chuck loosen up with the limited pressure I use.
I would agree with Bill on the amount of pressure required to tighten a chuck - at least as it applies to domestic species, which is about all that I turn. There is a significant mechanical advantage with the scroll mechanism and too much pressure can risk the chance of crushing the wood and possibly causing a fractured tenon. The formation of the tenon is critical and specifically the angle at the shoulder of the jaws. The outer edge of the jaws must contact the wood. Thus, for a Nova chuck with the dovetail lip on the inside surface, the interior angle of the tenon and form/waste should be 90* or less - never an obtuse angle that would leave the outside edge of the jaws unsupported. The clamping force is only part of the equation. The resistance against the outside of the jaws is equally important as it compliments the clamping force to prevent the piece from being “levered” out of the chuck. I very slightly undercut the surface of the form/waste to assure that contact resulting in marginally less than a 90* angle and do not have issues holding with 50 mm jaws.
George, speaking of tightening a chuck, I see many turners who tighten the chuck by cranking down with the key in just one of the two holes. If you tighten this way, have you tried tightening a little on one side, rotating and tightening a little on the other side, then repeating?Quote:
Originally Posted by George Troy Hurlburt
I found that the multiple tightening method gets the jaws much tighter with a gentler force on the key handle at each position. (This should be easier on the hands.) I suspect this is due to the mechanical tolerances inside the chuck - moving the key to the other side takes up a little more play in the mechanism each time. I heard a demonstrator describe this as "be sure to tighten in all six holes." I usually tighten "four holes" for smaller things and six times for larger. This is the same method recommended in machinist's guides to tighten Jacobs chucks on a drill press or mills/lathes. I've read that some Jacobs chucks such as those with internal ball bearings don't need this method but it doesn't hurt.
One problem with this, at least on my Nova SN2 chucks, is it is easier to get the chuck tighter so loosening it later is harder! That alone proves to me this method is a better way to tighten.
If you already use the multi-tightening method, maybe someone else reading will try it.
BTW, I hope people don't use a cheater bar/pipe on a woodturning chuck. I once bought a couple of used chucks from a woodturner who turned big bowls and REALLY liked to tighten the chucks so he used a cheater bar. (I wonder if this was due to bad experiences with pieces coming off the chuck because of poor technique or improper tenon/recess preparation.) He warned me the chucks were a little tight and needed to be "cleaned." Ha, I couldn't even close the jaws completely on one. I found they were both clean enough inside but the steel in the chuck body was actually warped from the excessive force, preventing the jaws from sliding smoothly. It took me hours to rework the chucks to make them work like new. If this guy had used the successive tightening method it would not have damaged the chucks.
JKJ
Agreed! Always use both key points to tighten - two rounds each with moderate force. I can’t imagine using a cheater bar. I don’t even use all the force I could with just my hand and I am not that strong.
I decided too post some photos of my chucks. The reason the Vicmarcs are my favorites are two fold. I like the points of where the chuck engages each time, I mark this point and when I go back and forth with the glue block all, goes back the way it was and I can see it. I do not use a cheater bar and will rotate where I insert the T-handle, at least I can see it and do not have to hunt for it, like on a scroll chuck. Second since there is no ridges on the end of contact, when I do the expanding into a recess it will leave no mark. On small platters, I can and do go down to as little as 1/16"recess. I hope you can see that in the photos. With the Nova chuck I have and I do use it, I don't like looking for the hole to place the movable key. I don't really care for the Scroll key(Oneways) and the serrations on the inside and that little ridge on the out side, again I do use them. I added in the photos a precision chuck, which are no longer made, that's all I had back in the 80's. Had a 3 jaw chuck once and sold it along with the Delta lathe. Big mistake I miss it. 30 year plus of chucks and attachments in photos. Now Paul, at some point like many of us you will want to add to your chucks, either for more capacity or just personal preference. By the way I started with a Shopmith in 1980 and still have it.
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I upgraded myself to the jet 1624,,i do have a g3 chuck which I do use but I also have the infinity chuck from nova,,the quick change jaws is what sold me,,,i believe the super nova is the same chuck but you have to remove screws to change jaws,,,the infinity jaws are a little more expensive but rather than having a lot of chucks that you have for one dedicated set of jaws,,,i figured I was way ahead by getting the infinity,,
I have several Nova's and a Vickmarc VM120. The VM120 feels "right" and the Nova's feel "wrong" when opening and closing the jaws. I think being left handed is the reason. Same thing with a screwdriver, easier to loosen a screw left handed.