Wanted: An accurate chuck

[Terry Vaughan]

I have Vicmarcs. I found runout on one but it disappeared when I made sure the insert was screwed right in. I thought I'd done that, but it hadn't quite bottomed out in the chuck body. The tommy bar hole was too shallow so it was hard to crank the insert right in without damaging it. I also found the chuck body would come off the insert instead of the insert coming off the spindle. Threadlock fixed that, now it works fine, no runout that I can see.

[Jim Underwood]

Just for thought, Jim.........if your insert is one that is a taper, like on the oneway, then there should be three screws that hold the insert to the chuck body. To make the insert seat plumb/true, then one needs to turn the holding screws in sequence, a turn or at most two turns at a time. If one tightens down one screw all the way, there is no way an insert will seat correctly. Turn a couple turns, go to next screw, tighten a couple of turns, go to next screw and so on until the insert is seated all the way down and tight. Not following this sequence can and does induce wobble into the chuck, so I encourage you to take the screws out of your inserts, and follow that proceedure. Not sure what to tell you on the Nova chucks, other than the off brand inserts for the Nova chucks sold by Woodcraft were faulty at times, and only a genuine Nova insert fixes it.

This is great information. Thanks to all who mentioned the faulty Nova inserts. I'll order one and see if that fixes the problem with my G3.

As for the Talon, I think I'll order some replacement jaws and see if that fixes it. I remember measuring the runout on that thing every which way and just couldn't find any...

[Fred Belknap]

This is just a shot in the dark but the picture you posted makes it look like the jaws may be install out of sequence. I took my Talon apart years ago and remember that it has to go together a certain way.

[Jim Underwood]

Lot of good suggestions here. I am not familiar with your Stratos lathe. How long have you had it, and have you had ANY chucks spin true on it? If it is a standard spindle thread - 1.25" x 8tpi, or other standard thread, I would spin the chucks on another lathe to see if you get the same issues. If not, then it probably is your lathe.

If the problems are still there, then Roger's thoughts on the Oneway chuck seem to be the next step with it. However, I would remove the jaws, make the correction on the insert as recommended, and see if the chuck body spins true. If not, then you may have an issue with either the insert or the chuck body. I would redo the tightening of the insert again. If it spins true, attach the jaws with the screws in, but not tight, close the jaws and tighten the screws in rotation. If it doesn't spin true, then you probably have an issue with the jaws.

On the Nova, make sure the insert is a Nova insert. See if you can borrow another insert to try. Remove the jaws and see if the chuck body spins true. Repeat same as with the Oneway chuck.

With regard to both chucks, be certain they shoulder up on the face of the spindle and don't just bottom out on the threaded spindle.

Jim, I know you are frustrated and I do hope this resolves for you.

There are so many possibilities here that I would exhaust all of them before I started blaming the chucks. Obviously, there can be and are occasional machining issues with chucks of any brand, but it just seems very unlikely you would have two chucks, different brands, that do not spin true.

The Stratos is brand spanking new. (I won the giveaway at the AAW Symposium this summer .) I doubt there's runout in the spindle, but I'll check. Both of these chucks (Talon and G3) had this problem on my Jet 1642, so I doubt it's the lathe...
I'm going to try to finish my review on it today.... There are some great features on this lathe, but there's room for improvement.

[William C Rogers]

Been an interesting thread. Being somewhat new I have not really noticed my chucks having wobble. How do you go about checking a chuck? Do you turn a piece of wood and measure that or do you measure directly on the chuck? What is considered acceptable runout and wobble?

[Joe Bradshaw]

I have been following this thread with much interest. Yesterday, I checked all of my Oneway Talon chucks for runout and misfitted jaws. I found no problems with any of them. They had various jaws(spigot jaws, #2 profile and dovetail, step jaws, #3 profile jaws and jumbo jaws). I agree with the others who say that your inserts may be the problem. Oh, and I tried my chucks on 3 different lathes. I hope that you gets problem solved. I really like my Oneway chucks.
Joe

[Leo Van Der Loo]

See this is the thing, it is not the Talon that is wobbling, the jaws are out, apparently the chuck was bought ON SALE, and I wonder if the jaws are actually genuine Oneway jaws, or some CHEAPER cloned jaws that were added to the chuck

It is the Nova chuck that is actually wobbling, and as we know that is nothing new, trying to make things CHEAPER by adding/using another than the original insert, ended up with headaches and problems, CHEAPER does NOT mean BETTER.

The pain of using a cheap tool lingers long after the joy of saving money has passed.

[Jim Underwood]

See this is the thing, it is not the Talon that is wobbling, the jaws are out, apparently the chuck was bought ON SALE, and I wonder if the jaws are actually genuine Oneway jaws, or some CHEAPER cloned jaws that were added to the chuck

It is the Nova chuck that is actually wobbling, and as we know that is nothing new, trying to make things CHEAPER by adding/using another than the original insert, ended up with headaches and problems, CHEAPER does NOT mean BETTER.

The pain of using a cheap tool lingers long after the joy of saving money has passed.

The Talon was bought on sale, but I believe the jaws are OEM, unless Hartville put some clones on there... I certainly didn't.

As for the Nova, I could have sworn I bought a genuine Nova insert, because I distinctly remember opening two red/black boxes with Nova inserts- one for my G3, and one for my Midi chuck.

But today, I bought some #2 smooth jaws for the Talon, and a "genuine Nova Insert" for the G3, and should have them this week. Then we'll see if anything gets corrected.

[Jim Underwood]

Today, I received the Gen-U-Wine Nova insert for my G3 chuck. I checked runout on the OD of the G3 chuck before installing. I had .002" at the very back of the chuck OD, and .004" runout in the midline between the keyholes and the scroll jaw base cutouts. (The back and the midline are about the only place one can have full contact around the circumference.) I also noted the "wobble" at the front when the toolrest was brought quite close to the front corner of the chuck. It did wobble significantly.

Then I removed the old insert, and inspected it. It has the same "L" stamped in it as the new one, which designates the 1-1/4" x 8 tpi Nova insert. This seems to confirm that I had indeed bought a Nova insert for this chuck.
Nevertheless I installed the new one, and remeasured the runout. It now has about .001" runout at the back and .002" runout at the midline. It was noticeably less wobbly also. I found this mostly concentric chuck body acceptable.

Once I did that, I removed the jaws, placed a straight rod between the bare jaw bases, and tightened the chuck down on the rod, and measured the runtout. It was less than .001". I find this acceptable.

Then I installed all three sets of jaws in my possession that fit this chuck and inspected them. I have the original dovetail jaws it came with the chuck when new, a set of step jaws, and a set of pin jaws.
However, EVERY SINGLE ONE of the jaws I own for this chuck, have the same twisted aspect illustrated in the drawing I shared earlier. This indicates that the manufacturer hasn't machined these jaws correctly. In each case ONLY the leading edge of each jaw contacts the work piece. And, the part of the jaw that does NOT touch misses touching by a significant amount. I did not measure, but I daresay it's at least .030" off.

I then checked my Oneway Talon, which exhibited the same problem and found that although the chuck body runs true, the jaws still have the same problem they originally had. Now I'm supposed to received the new dovetail jaws tomorrow, so we'll see if they exhibit the same problem....

This just irritates the $%!! out of me.

[John K Jordan]

...EVERY SINGLE ONE of the jaws I own for this chuck, have the same twisted aspect illustrated in the drawing I shared earlier. This indicates that the manufacturer hasn't machined these jaws correctly.

This is incredible. I have 14 Nova chucks of various types, some old, some recent, and I have no idea how many jaws. I have NEVER seen in any jaws or chucks the type of misalignment you described with the drawing. All of my jaws make perfect circles, at least within the tolerances of the very slight play in the slides.

If ALL the jaws you have mounted show this problem, I would suspect the grooves in chuck for the slides are not machined perfectly radially (or less likely, the slides are bad). If each was tilted a bit, every jaw you mounted would show the same problem. Do you have any way to test one of these problem jaws on someone else's chuck, perhaps one at a store?

In fact, when you first posted the diagram I was puzzled, how could they even make jaws that tightened rotated like that? They apparently machine the jaws in one piece, stepped locating ring on the bottom and everything, then saw them into four pieces. How could the location ring on the bottom of each jaw even be machined with a tilt relative to the front of the jaws unless, perhaps, the ring was not milled concentric with the jaws and then the jaws installed out of order? (That's a stretch!)

If the the jaws were not installed according to the procedure in the manual they might not line up correctly but still, the individual jaws wouldn't be twisted. If the jaws were installed out of order they will likely have uneven gaps between them, but it's hard to imagine them with a twist.

Try this: hold the jaws together (in the correct order) so they form a circle, working side down on the table, perhaps holding them with a rubber band if necessary. Does the location ring machined on the bottom side make a circle and is the circle concentric with the outside circumference of the jaw set?

Do you ever get up to Knoxville? If so, I'd love to examine your chuck and jaws and compare it to mine.

JKJ

[Van Huskey]

While I normally have very little to say in this corner of the forum and this thread isn't even about bandsaws, it is blindingly obvious to me what the problem is and I am completely flabbergasted that no one has identified the obvious. Jim simply used every bit of tool karma and luck in one shot winning the lathe, he is simply doomed to lead a life of disappointment and despair when it comes to new tool acquisitions, at this point anything less than 1/10th of an inch of runout in a chuck should be seen as a victory to be celebrated.

More germane to the thread and certainly more important to my spinny thing education is what is considered acceptable runout for a lathe/chuck/jaws "system"?

[John K Jordan]

More germane to the thread and certainly more important to my spinny thing education is what is considered acceptable runout for a lathe/chuck/jaws "system"?

Runout and wobble are not as important on wood chucks as they are on metal, partly because the wood compresses as you tighten the jaws and precision is naturally lost. Also, since you always true up the blank just after mounting, the piece will always be perfectly concentric with the axis of the lathe spindle itself regardless of how imprecise the chuck and jaw combination is.

Concentric jaws with low runout are in fact helpful when remounting things in the chuck but even that's not very important when using the recommended method of marking the position before removing the piece and taking care to reset the piece in the same jaw indentations every time. Due to the nature of wood, remounting is inherently imprecise.

Perfect jaws and chuck are also helpful if you first turn a tenon between centers and then insert that tenon into the chuck, seating it against a carefully turned shoulder. If there is wobble caused by tilt of the jaw axis, the amount of error seen at the free end of the piece would depend on the angle and the length of the piece. The worst that can happen is you may have to decrease the diameter a bit more than if the chuck was perfect.

If you turn a lidded box, you generally turn TWO tenons between centers, one on either end of the blank, divide the blank and mount each one in the chuck to turn the lid and the base. A perfect chuck would help keep things straight at first and help preserve the full diameter of the blank. However, even when turning boxes an imperfect chuck is not necessarily a big deal since both parts of the box including the mating surfaces are, again, always concentric with the axis of the lathe spindle. There is never a need to remount either part in the chuck, at least not using the method I use, taught by Richard Raffan.

All that said, I don't know of any numbers for "acceptable" runout on a woodturning chuck. I would also be very unhappy with a chuck that had visible wobble, either from parallel axis offset or angular tilt. If I pay good money for a chuck, I want it to be right. How far out it can be and still be useful is a personal issue. I don't see wobble in mine but I have never put a dial test indicator on one either.

BTW, the worst case for a chuck that is tilted off axis is when turning long, thin spindles with one end held tightly in the chuck and the other free or held by the tailstock. If the spindle blank is slender enough, the angle will be compounded by the relatively long distance to the end and there may not be enough wood left at the end for the desired diameter. However, two things help even with this: when turning a square blank I insert it loosely into the chuck, line it up visually with the ways or the point on the tailstock center, then tighten the jaws. The square blank held in the gaps between the round jaws is deformed enough to correct for any reasonable error in the chuck. Or far better: I often "chuck" thin spindles by turning a short morse taper on the blank (as discussed in another thread) and use the spindle taper as a jam chuck. This has several advantages, one being the work can be removed and remounted as often as I like and it is always perfectly registered.

JKJ

[Jim Underwood]

While I normally have very little to say in this corner of the forum and this thread isn't even about bandsaws, it is blindingly obvious to me what the problem is and I am completely flabbergasted that no one has identified the obvious. Jim simply used every bit of tool karma and luck in one shot winning the lathe, he is simply doomed to lead a life of disappointment and despair when it comes to new tool acquisitions,

HA HA HA! Thanks for the laugh. I needed that...

at this point anything less than 1/10th of an inch of runout in a chuck should be seen as a victory to be celebrated.

I hope you're not equating 1/10 (.1") with ten thousandths (.010")...

More germane to the thread and certainly more important to my spinny thing education is what is considered acceptable runout for a lathe/chuck/jaws "system"?

Now there's a darn good question. I'd like to know what tolerances these manufacturers hold to...

[Jim Underwood]

This is incredible. I have 14 Nova chucks of various types, some old, some recent, and I have no idea how many jaws. I have NEVER seen in any jaws or chucks the type of misalignment you described with the drawing. All of my jaws make perfect circles, at least within the tolerances of the very slight play in the slides.

If ALL the jaws you have mounted show this problem, I would suspect the grooves in chuck for the slides are not machined perfectly radially (or less likely, the slides are bad). If each was tilted a bit, every jaw you mounted would show the same problem. Do you have any way to test one of these problem jaws on someone else's chuck, perhaps one at a store?

Now there's an idea. I'll see if my friend up the road has a Talon, and we'll mount these jaws on his chuck. I'm trying to remember who else might have some Nova Chucks.

In fact, when you first posted the diagram I was puzzled, how could they even make jaws that tightened rotated like that? They apparently machine the jaws in one piece, stepped locating ring on the bottom and everything, then saw them into four pieces. How could the location ring on the bottom of each jaw even be machined with a tilt relative to the front of the jaws unless, perhaps, the ring was not milled concentric with the jaws and then the jaws installed out of order? (That's a stretch!)

I was thinking about that last night. For these jaws to be out this bad, they'd have had to be milled separately after being cut apart wouldn't they?

If the the jaws were not installed according to the procedure in the manual they might not line up correctly but still, the individual jaws wouldn't be twisted. If the jaws were installed out of order they will likely have uneven gaps between them, but it's hard to imagine them with a twist.

I know, right? This is so frustrating...

Try this: hold the jaws together (in the correct order) so they form a circle, working side down on the table, perhaps holding them with a rubber band if necessary. Does the location ring machined on the bottom side make a circle and is the circle concentric with the outside circumference of the jaw set?

There's a thought. I'll take a look this evening when I get home. The new jaws for the Talon will probably be here, so I'll mount them and see how they're doing as well.

Do you ever get up to Knoxville? If so, I'd love to examine your chuck and jaws and compare it to mine.

JKJ

Nope. Never been there. I could possibly ship you a set though... Be easier if I could try it on a local set though, obviously...

[John Keeton]

With regard to Nova chucks, it has always been my understanding (not sure of the original source) that the jaws were milled as a unit and then sawed. Setting them together on a flat surface - table saw - should reveal any distortion. Same for setting the chuck upside down on a flat surface. One should be able to perceive if the slides are out of kilter.

I do agree - somethin' ain't right!! I do hope you get it resolved so you can get back on the lathe and not be burdened by this.