G3 Chuck users.....something doesnt seem correct with mine....help :)

[John K Jordan]

George, It sounds to me like the threads for your chuck or insert are either bunged up or machined incorrectly. I have 11 Teknatool chucks, some G3 and most Supernova and Supernova2. I have inserts for my lathes from several sources. (I hate to change jaws.) The runout is better on some jaws/chucks than others but it is minimal and acceptable. I don't use the locking set screws and have NEVER had a chuck or insert come loose, even with large bowls. (Perhaps this is because my lathes accelerate very gently when spinning up and down and never "jolt" the work.)

i would take a close look at the threads. If you bought this locally, perhaps take it to the store and have them test the insert and chuck with a different chuck and insert. Otherwise, you might take it to a local turner who has the same equipment. I am assuming you have the right insert for your lathe - can't imagine the wrong one even partially fitting (you can check the number stamped on the hex flat.)

Note that as you tighten the jaws on the stock it can easily be accidentally jacked to one side as the jaws bite into and crush the fibers, especially when chucking square stock without a tenon. (Incidentally, you can take advantage of misalignment when tightening the jaws to turn multi-axis pieces.)

BTW, this is how I mount long spindle stock in a chuck: If the stock is too large to mount square or quite long, I mount between centers and turn a tenon on one end, making sure to cut a sharp shoulder and making sure the tenon is not so long it bottems out in the jaws. I usually mount between steb centers, both at the headstock and tailstock. If I plan to mount a turning square without using a tenon, I mark the center of the right end and if the wood is hard, make a small hole (with a gimlet). I put the stock in the jaws and barely snug them, then bring up the tailstock (with the live steb cinter) and advance the point into the center hole. Then I tighten the jaws firmly while cranking down on the tailstock. This method keeps the work centered precisely since it can't shift as the jaws dig into and somewhat deform the gripped surface. I use roughing gouge or skew to round the length then remove the tailstock. I often turn 1" to 3" blanks 6" to 14" long.

If the stock is relatively short or I have more thichness than I need, I don't use the tailstock to center but just eyeball it from above, aligning roughly with the lathe ways while tightening the chuck, first on one axis then when rotated 90 degrees. When I have just barely enough wood thickness (i.e. want to make a 1-7/8" piece from 2" stock) I always use the tailstock to aid in centering - it lets me get very close.

In case you don't know, chuck jaws will grip the best on a round tenon a wee bit larger than the jaw's smallest diameter. This not only grips the best but deforms the wood (crushes the fibers) the least.

Also, I make a mark between jaws #1 and #4 in case I have to rechuck the work at some point. And here's a drilling tip for no extra charge: I always start a hole with a machinist's center drill. These are short and stout and get the hole started correctly even with wild end grain. Set of 5 different sizes are very inexpensive on Amazon (for wood, the high-dollar center drills are not needed.)

While on my chuck soapbox, I recommend to get and use a proper wrench to tighten and remove a chuck. I cringe when I see someone put in and whack the chuck key with their hand or piece of wood. I once bought three used chucks from a gentleman who abused them this way and worse: he used a cheater bar to get them REALLY tight. I've never seen chucks in worse shape. The steel in the bodies was actually deformed at the jaw slides to the point that I could barely adjust the jaws. It took me hours to rework them.

JKJ

[Ron Rutter]

George. It sounds to me like you are not starting out correctly. Mark the center of the tailstock end of the piece. Put the turned end in the chuck & bring up the tail stock to mark. Tighten up chuck end ( shoulder in place) with tail stock centered in piece. Ron.

[Michael Mills]

. I don't use the locking set screws and have NEVER had a chuck or insert come loose, even with large bowls.
JKJ

Interesting. I don't have as many chucks but I do always use the set screw in the body of the chuck to lock it to the insert. I really don't see a reason not to unless you are switching chucks between lathes with different spindle sizes (changing inserts). I seldom use the other set screw from the insert hex to the spindle; I just use a lighter touch while sanding in reverse but for safety I really should use it any the time in reverse.

Seems to me not using the set screw in the chuck body (as the OP did) could easily result in the chuck unthreading from the insert upon removal from the lathe leaving the insert on the lathe. There may well be greater force in the insert/spindle mating than in the insert/chuck body mating; especially if the chuck was placed on the lathe in "hero" method as described by Capt. Eddie.

[George Farra]

Hi Everyone,

Thank you all for your input. From all of the posts I am concluding that my technique was completely wrong, in that I was tightening the jaws without having the tailstock in place. Also on a square blank I was bottoming out the blank in the chuck. I never made it back into the shop last night and looks like my next go around will be this weekend.

I will change my technique and see if my problems go away. I will also post a follow up regarding the chuck wiggling off the adapter because I am still stumped as to how that happened considering the lathe is spinning the chuck in the opposite direction of the threads.

Regards, George

[Kyle Iwamoto]

Your chuck loosening. No offense intended, but are you turning in the right direction? I do know from experience that a skew CAN cut with the lathe running in reverse. I remember thinking, why is my skew bouncing up and down. I don't recall that before. I should put MORE pressure on it so it won't bounce. I also know that a band saw can cut with the teeth in the wrong direction (up). And I checked it 3 times. I remember thinking this is a NEW blade. Why is it such a POS. Don't be embarrased about making misteeks we all do it.

[George Farra]

Evening all,

I checked to ensure there is nothing preventing the adapter from fully seating in the chuck. The internal threads on the chuck are all clean and the the adapter bottoms out in the chuck body. I also made sure the lathe was running in the correct direction

I prepared a new 2x2 square blank and marked the center on 1 end. Used an awl to mark the center. Slid the blank into the chuck jaws without bottoming the blank out in the chuck. Brought the tail stock up and got the point set in the awl mark, held the stock and tightened the jaws. Spinning it by hand I could not detect any visable runout. I started up the lathe and let it come up to 950rpm, then i cranked it up to 1100 rpm. Ran smoothly for about 10-15 seconds and then I started to notice a vibration. Shut it down and sure enough the chuck came loose from the adapter.

I took everything apart and this time I inserted the grub screw to hold the adapter in place. i used the little red plastic dots to protect the threads. Used the same set up procedure and this time it ran okay although i still noticed a vibration develop after about 10-15 seconds of run time.

At this point I'm thinking its best for me to return both the chuck and the adapter and try it again with fresh equipment. I sent Teknatool an e-mail yesterday about this issue and I have not yet heard from them.....what a difference from Rikon customer service. The guys at Rikon are super responsive.

Not sure what to do/try differently at this point

George

[John K Jordan]

Very strange. Was the vibration with the set screw in place also accompanied by a loosened insert or was it still tight? If the insert is still tight (when you remove the set screw) I would want to try that chuck on a different lathe and/or try a different chuck on that lathe. Do you know someone who has a chuck and/or insert you can try? I can't imagine the vibration being due to an imbalance in the chuck since it should vibrate immediately and not wait 10 seconds.

But if it still loosens wirh the set screw in place, and assuming both threads are in good shape and you have tightened securely with a wrench, perhaps some blue loctight would help.

I also assume you have tested to be sure the vibration is not coming from the lathe itself, with no chuck installed but with a blank held between centers or faceplate or jam chuck. And I don't temember if you said, but be sure the tailstock is aligned perfectly with the headstock - not only do the points need to touch exactly but the axis of the headstock spindle should be parallel to the ways and the axis of the tailstock.

JKJ

[Jack Mincey]

At what RPM are you turning your spindle? The vibration could be due to turning with your chuck at high rpm's. Just a thought.
Jack

[George Farra]

Hi Guys,

The lathe comes up to speed at 950rpm and I turned it up to 1100rpm. The vibration occurs 10-15 seconds in at 1100rpm. I will try running the same blank between centers at the same rpms tonight and see what happens.

I didn't remove the set screw prior to removing the chuck from the lathe to see if it was indeed loose after releasing the set screw. I can also try that tonight as well.

I will keep you all posted, thank you for all your help

George

[John K Jordan]

Any lathe I've used would easily turn 2000-3000 RPM with no vibration. I typically turn all my spindles at over 3000 for a cleaner cut.

Check the drive belt too. I have never had this happen but I've heard of other cases where a vibration was caused by a bad belt. Dust buildup in the motor can also cause vibration. Bad bearings too, but this is usually pretty obvious even turning by hand.

JKJ

[Joe Bradshaw]

George, your location would help. I'm sure that there are some "Creekers" near you and would be glad to help you sort this out. Check and see if both ends of your lathe are level. Solving your problem is going to involve a lot of trial and error. As someone has mentioned, try another chuck on your lathe. Try your chuck on someone else's lathe. If all else fails, sell your G3 and get a Oneway Talon with the proper insert. Good luck.
Joe

[George Farra]

Hi Guys

I spun tool handles between centers at 3,000rpm just last weekend without any vibration which is why I am focusing on the chuck or the insert adapter. I was looking at the Oneway Talon chuck this morning and have to admit their tapered insert intrigues me. I think I am going to order one with the 1x8TPI adapter. I can always return the Nova chuck as I bought it 2 weeks ago.

I am in NJ, Bergen county.

Thanks

George

[George Farra]

Hi All,

took another go around at it tonight. took a brass brush to the threads on the chuck, mounted the adapter into the chuck and tightened it with a spanner wrench. I did not use the set screw.

Prep'd a new 2x2x16 blank, marked the center on 1 end, made a detent with an awl. Got the live center point set in the awl mark and tightened up the jaws making sure the blank was not bottomed out in the chuck.

Started up the lathe and got her running up to 2800rpm....ran smoothly, no vibration. Shut it down pulled the tailstock and the chuck was still tight on the spindle. Suddenly I was happy.

Next I ran the lathe up to 3000rpm with the blank in the chuck without the live center...just spinning freely. All was okay.

Lastly, I put a jacobs chuck in the tailstock and drilled out a hole in the center of the blank. At this point I did notice that drill bit wasnt lining up perfectly with the awl mark....not off by much, just a hair off center. I drilled out a hole and as I was backing the drill out, I noticed it started vibrating. Lathe was running at 950rpm. Shut everything down and sure enough the chuck was loose on the adapter. the adapter was always rock solid on the lathe spindle.

Thoughts.......improperly machined adapter? chuck? or is this a situation where I would always need to use the set screw??

I am leaning towards purchasing a Oneway Talon...15% off at Rockler. If that chuck doesnt give me any problems....the Nova gets returned

Thanks

George

[Thom Sturgill]

Sympathetic vibrations tend to peak at specific speeds. It is not uncommon in spindle work to have to turn the speed up until a vibration dampens down. So the questions are:

Did you check the spindle (between centers) at 1100 rpm where you had noticed vibration or did you just turn the speed all the way up and not see vibration?

Did you try checking the chuck alone at different speeds?

Are you using one of those plastic washers under the chuck? They have been known to create vibration, and to cause the insert to stick while the chuck spins off when the motor stops too quickly if the grub screws were not in place.

I have one chuck (out of seven) that always requires a wrench to remove. Before I tightened the grub screw the insert would unscrew when I tried to simply unscrew the chuck by grabbing the chuck body and locking the spindle. So not all inserts are created equal either.

[George Farra]

Hi Thom,

#1, yes. I started at 950rpm and let the lathe come up to speed. Moved it up to 1100rpm and let it run, and after that I ran it up to 3000rpm. This was done with the tailstock in place.

#2, yup, after being satisfied that it was running smoothly with the tailstock in place, I removed the tailstock and ran the blank just with the chuck for the same 3 intervals as above.

It ran smoothly again at all 3 rpms, each interval ran for about a minute. In each of the runs above the red washer was in the grub screw hole, however the screw was not installed.

It came loose as I was drilling a hole in the center of the blank, which would have been the third time spinning the blank in this session. I had a Jacobs chuck in the tailstock and drilled a hole about an inch and a half deep, running the lathe at 950rpm. As the drill bit was exiting I started to notice the vibration.

On shut down the lathe slows down gradually so I cant see how that is the cause. I do believe its the adapter since in all instances the chuck was loose on the adapter but the adapter was rock solid on the lathe spindle. In fact, unless the set screw is in place, the chuck will come off the adapter when I remove it from the lathe and I need a wrench with the spindle lock on to get the adapter off the lathe.

I was thinking about it more last night and it seems the solution is to put the set screw in and leave it in, rather than buy the Oneway Talon. The chuck operates smoothly and I like the fact that Nova jaws are interchangeable across all their chucks so upgrading later is an easier investment.

Thanks for all your help,

George