Dilema(new to turning)

[Dave Stoler]

Nova chuck...Second practice bowl. First one was slightly out of round . When I did the inside the lip (?) was not even all the way around. Now on my second try I,ve got the same thing. I use the screw thingy first and turn the outside and foot (the part that go,s in the chuck) and when I take the screw out and clamp the foot in the chuck the angle matchs great and the bottom of the bowl is flsh againest the chuck..I,m doing this on the fly and obviously i,m missing something somewhere..

[Ken Fitzgerald]

Dave,

I've not been too successful using the screw attachment for the chuck. Let me suggest...place the bowl blank between the drive center in your head stock and the live center in your tailstock. Orient the future inside of the bowl towards the drive center. Now turn a tenon on the bottom of the bowl which should be facing your live center in the tailstock. Also turn a good flat shoulder where the tenon meets the bowl. Keep in mind, you don't want a tenon so long that it bottoms out in the chuck. You want the chuck to grasp the tenon but it's the shoulder resting on the jaws of the chuck that take the forces applied while turning the bowl.

While you have the blank between centers you can also turn the outside of the bowl.

If you are turning a green blank, keep in mind it will probably distort while it's drying resulting in a distorted shape. That's why most people rough turn the thickness of the walls of the bowl to 10% of the diameter of the bowl. Then you friction chuck the dryed roughed out bowl between the chuck and the live center......return the tenon to perfectly round....then mount the tenon in the chuck and finish turn the bowl. I hope I'm making sense.



Good luck!

[Bernie Weishapl]

Dave I agree with Ken on this. I don't use the screw because I haven't had good luck with it. The only difference is instead of turning between centers I use a faceplate. I center the faceplate on the blank to turn the outside and making the tenon. Don't make your tenon over a 1/4" long or so as Ken said so it doesn't hit the bottom on the chuck. Make very sure the surface your jaws fit against are square and straight. If I remember rightly the Nova chuck is like my Vicmarc and you need to dovetail your tenon so it grips tight. When I have the bowl in the chuck I finish the outside making sure it is round. and then go to the inside. Green bowls under 10" I leave 3/4" thick for drying and over that I leave at least a 1". I would get a couple of good DVD's on bowl turning to watch and then practice

Good luck and keep trying.

[Ken Fitzgerald]

Dave........Bernie's right....using the faceplate to turn your tenon is an even better idea......Duh! on my part!

[Andy Hoyt]

Nuthin' wrong with a screw chuck.

Here's Dave L. just last month using one (http://www.mainewoodturners.org/lancaster_2007_04.jpg)

[EDDIE GLAZE]

I Agree With Andy. I Have Turned 18" Bowlws This Way.

[Steve Schlumpf]

Dave - I use the woodworm screw on my Talon chuck for just about every bowl I turn and find it works very well. For very large out-of-round blanks I use a faceplate. Trick with seating tenons is to make sure the tenon doesn't bottom out in the chuck and also that the shoulder area fits tightly. I usually grab a parting tool and clean up the shoulder area just before removing the blank and fitting the tenon into the chuck. Hope that helps some.

[Allen Neighbors]

All the above is right on, as far as I'm concerned... ('cept them strange folk that use the screw chuck :D [kidding, Chaps]) I always use the spur drive that came with my SuperNova2 on smaller bowls, and turn the tenon on the tailstock end, between centers. On larger bowls, I use a faceplate.

[Raymond Overman]

When you reverse the piece you may need to re-center the turning and true it up. Take some light cuts on the outside from the largest diameter to the smallest. Remember the geometry. The furthest away from the headstock, the more pronounced the wobble will be. By truing it up after reversing you should eliminate the out of round problems.

If this doesn't work, you may need to look at your headstock bearings or possibly the alignment of your headstock and tailstock. Vibration can also cause some of this problem so additional weight on your lathe may be necessary.

[Paul Engle]

Dave , two,three things affect the bowl when it does like you stated, one is if the face where the screw chuck screwed into is not mostly flat, when chucked up by the foot or tennon will seem to be out of round. two, if the screw chuck moves / moved after you turn the tennon / recess/foot ... it will throw the rim off also. If the piece is out of balance , lots of voids,sap wood versus heart wood etc. , it will not balance and that will throw you off also. I suggest you check these three , true up the inside/outside of the rim after you turn the tennon/recess , then reverse it and see if that does not help some what.

[Steve Campbell]

Dave each of the jaws on your chuck should have number stamped on them. Make sure that they are installed in the right number slot.

Steve

[Dave Stoler]

I have the numbered jaws in there respective places...
It just perplexes me that a chuck of this quality wouldn,t have factored in this kind of situation in there manual or web site..I,ve checked both.I,ll stay with it til I fiquire it out...
I,m useing a 1/4 in tenon with the correct angle and the bottom of the bowl sitting flush againest the chuck..
I was also instructed by a friend to use the tail stock while turning the tenon to help keep thing true.
I will continue the quest for concentricity !!

[Dean Thomas]

Have you checked the alignment of your lathe? Put your spur center and your live or dead center in the tail stock, push the tailstock to the head, and make sure that the points align perfectly. If your headstock is slightly off center, it can cause that kind of stuff. It ain't always the tailstock that's the culprit!

Have you made sure that nothing ugly is under the jaws or under the chuck itself? If the chuck or the jaws are not clean, they can cause misalignment as well. More stuff to check...

[Dave Stoler]

I am perplexed that a chuck of this quality would have this issue and that it is not addressed in the manual or website. I will try all advise given here until I find the problem.
Another friend told me to use the tailstock on center to help steady the piece while turning the tenon .
I went back and double checked the jaw numbers to be sure and they are correct. My search for concentricity continues.
I shall " endeavor to perservier" :D from the movie..Jerimiah Johnson

[Dean Matthews]

I use the woodworm screw all the time and I have not hit this problem.

Couple of questions:

are you doing green wood or dry? If it's green... not surprising that you are going out of round.

When you make the foot so that it goes on the talon chuck are you chucking to the inside or the outside? When I do mine I cut a recess into the wood and then expand the chuck jaws inside of the recess. Everytime I have tried to do a solid piece on the wood and "grip" the wooden tenon I have had out of round issues.

How are you making the piece you are putting into the chuck? Are you using a gouge, scraper, parting tool? I do not have the dovetail jaws but I do angle the lip in slightly using my parting tool.

[Dean Thomas]

I am perplexed that a chuck of this quality would have this issue and that it is not addressed in the manual or website.
You can buy $200 shoes and they don't tell you about fixing the insoles to suit your foot and they don't tell you to remove stones either. Heck, if the shoes are from "offshore" the durned tags are probably misspelled!

I hope you know I'm not shooting at you with the above comment. They just make a lot of presumptions and don't give instructions to speak of in ANY language. These are all things that we've learned either the hard way on our own or from someone else's hard way. Try not to be too frustrated. It's a booger having a tool that isn't working the way you think it ought to. I had to realign the head on my Jet 1236. I was doing a little bowl and it exploded on me, sending pieces everywhere. I violated the first rule of woodturning, that the inside diameter must never exceed the outside diameter. It went off with a bang and evidently nudged my headstock a tad. I had a couple of pens that simply did not fit right as a result but was too slow on the uptake to realize the cause. Fixed now and MUCH better. Wish I had them pens back. Had too much stuff on one side of the tube and not nearly enough on the other side. :( It's amazing what we learn "on the way".

[David Wilhelm]

Dave, my first chuck was a nova. I had the same or very near issue as your are having. What i found was when i used my worm the chuck would not stay tight. I talked to teh guys and woodcraft, checked and rechecked every thing and it still would not stay tight. I never had a problem with it not holding a tenon but for some reason if i placed the worm screw in it and started turning a blank it would back off just enough to make it some what out of round. I nolonger use that brand and have never heard of anyone else with the same problem but it may be worth a look.

[Dean Matthews]

Dave, my first chuck was a nova. I had the same or very near issue as your are having. What i found was when i used my worm the chuck would not stay tight. I talked to teh guys and woodcraft, checked and rechecked every thing and it still would not stay tight. I never had a problem with it not holding a tenon but for some reason if i placed the worm screw in it and started turning a blank it would back off just enough to make it some what out of round. I nolonger use that brand and have never heard of anyone else with the same problem but it may be worth a look.

it backed off? How the heck did that happen? With the one I have the cutting action would cause it to spin in the direction that would tighten it.

Do you by chance have the wrong threaded screw? I know that oneway makes both left and right screws for this.

[Ken Fitzgerald]

:( It's amazing what we learn "on the way".

Dean,

I unpacked my PM3520B a couple of weeks ago. Cleaned off the grease. Got ready to turn a few Christmas ornaments. Put the drive center in the headstock and the live center in the tailstock. They don't line up. I pulled the headstock and cleaned the bottom carefully. Removed and cleaned the tailstock surface...checked the bed ways...cleaned.....

Tried again....better but still doesn't line up correctly.....I'm starting to get a little riled and disappointed......then I thought....wait a minute....removed the two centers. Took my knockout and a piece of paper towel soaked in DW-40...pushed it through both of the #2 morse tapers ...on the h/s and t/s....then pushed a clean paper towel through....bingo! They line up.

[David Wilhelm]

The worm didnt' back out of the blank. The chuck would loosen up around it. I was thinking that i was putting it in ther chuck wrong. I even took the thing with me drove and hour and the guys at the shop put my chuck on a lathe and tried it. did the same thing. I came home with a talon and I love it. Now the one i had trouble with was a midi with the thumb bars and i've got a big one that i've never tried the worm on because i don't have the worm :(

[Dave Stoler]

What I did was make a really shallow tenon(1/8 in) with the correct bevel of course and viola..When I spun it around it was only very slightly off. Very slight..I think I can live with this.
And when I did the inside it held firm and never loosened.

[Dean Thomas]

Just so I don't presume my way into oblivion, I'll ask again. Did you check alignment on your head/tail stocks?

If you've got the lathe I think you have, your headstock can move. I really messed up a couple of pens after blowing up a small bowl with a crack that became shrapnel. Left an interesting natural edge saucer...

The blowout apparently caused the head to move a smidge. Made my mandrel about 1/8" out at the end of its world which was more than enough to bow the mandrel and make oval joints instead of round. Too thin on one edge and too fat on the other. Not a nice feeling. Re-aligned and reduce the problem by 90%, but there is still an ovaling problem. Checked and at least one of my mandrels does not fit my Morse taper hole well at all. Sucks in fact. Now I have other issues to conquer in my quest for pen barrels that perfectly match the hardware. And I'll probably end up with some new bushings, too, as I've discovered that some of them (even the new ones!) are simply not tolerable when it comes to round and equal on the mandrel!

The real point is that just 'cuz we set the bloomin' machines doesn't mean that they'll stay where we put them! And we've all learned that we can't trust everything to be or do what it claims, right?

May I hi-jack your thread, sir? :rolleyes: Maybe I'll split this one off and start it fresh on the ovaled pen blank thing...

[Dave Stoler]

The lathe is a new Jet mini 12/20 (?) and when I brought the tail stock up to the head it met nearly perfect..Needle to needle within less than a hair.
As far as hi jacking..I learn from ever post I read so no problem..
The only question I have is since I am useing the woodworm screw then chucking the tenon i,ve made back into the chuck how would tailstock alignment effect this procedure?
I,m new and learning.

[Dean Thomas]

The only question I have is since I am useing the woodworm screw then chucking the tenon i,ve made back into the chuck how would tailstock alignment effect this procedure?
Actually, the alignment from EITHER end can affect that alignment.

By aligning your head and tail stock, the goal is to make sure that you have only ONE AXIS. When you align, find out where your tailstock is in relation to the ways. Most of the home shop lathes (including Jet) have some amount of play in the tail stock, front to back as you face the working side of the lathe. Just a little. I align mine so that the tailstock always rests firmly against the back rail. That's where it seems to be most stable for me. You line 'em up and spin the drive spindle to make sure that it stays aligned during rotation--no run-out, no false alignment issues.

If you mis-align your centers and you turn a tenon on the tailstock end, that exaggerates the misalignment. When you go to center up a piece that's say 5" thick, you could be 1/16 or even 1/8" off center! That's a lot. If you've done a finial that's fairly thin and your tailstock was off, forcing your spindle into a false center, you end up turning an eccentric form, not a round one. And the longer the distance from the drive side, the greater the issue of out-of-round experiences becomes!

If you're dealing with a pen and 1/16" off in your alignment, you create skinny spots of wood on your tubes which creates bad fit against the presumed roundness of the kit's hardware. Want me to ship you a pen so you can feel that ugly little lip where your fingers hold it to write? That should be tactile-ly seamless, but the turning device has to be precisely aligned in all those ways in order for that little lip to go away. That's my current quest. The smaller the amount of wood, the more important that little wobble becomes! :eek:

Does that help explain why alignment on both ends is important?

[Bob Hamilton]

Dean, I believe he meant he was using the woodworm screw without tailstock support and then reversing on to the chuck, also without tailstock support, so the alignment of the tailstock would have nothing whatsoever to do with the shape or location of the tenon. The explanation you gave would make sense if he was starting the blank between centers.

Take care
Bob

[Jerry Pittman]

I have had a problem with the chuck, G3 & Titan, holding the woodworm screw tight in the chuck long enough to get the outside done. Even using the tailstock for support helped but didn't completely solve the problem. Oddly enough, the spur center for the chucks stays tight and works great.
Jerry