Chuck question

[Rob Bourgeois]

Yesterday I started my first bowl on a chuck( Penn state bargin chuck). I turned my tennon about 1 1/5 inches in diameter and about 1/2 long. Much within the parameters of the chuck. The blank was only about 5 inches in diameter and about 5 to 6 tall. It was cedar and fairly dry.

I had turned the outside profile using a face plate and had flipped it around to start on the inside. After fussing with the placement a bit, the blank was centered very nicely. During the turning of the inside, I hit a catch and the bowl dropped out of the chuck. I rechucked it and tighten it even more. Then I started again. This time I hit the same branch/crack /catch and the bowl left the lathe and landed in the driveway after bouncing around the garage. One second it was there, the next it was gone. So after a qucik change of underwear-(hey I am new at this), I looked at the bowl and it had cracked pretty good done the side and had other chunks missing including part of teh tennon---not worth turning.

So my question after all that is....what did I do wrong? HOW tight do you tighten the chuck. It had started digging into the wood. I know this chuck has worked for some of you..cough cough...Kurt:p Any help will be appreciated before I turn another perfect outside profile with no tool marks(first time--with no sand paper) only to see it fly away and get screwed up.

[Rich Stewart]

That must have been a heck of a catch. I have had some REAL goodies and I never had a workpiece fly out of the chuck. I have the same utility chuck from PSI. Also turn a slot in the bottom of some bowls about a quarter inch deep and expand the jaws and have never had a piece fly off. I do crank it down pretty hard. The only problem I had was the piece not running true after being rechucked. very slight wobble but now i can get it running true after a couple tries.

[Steve Knowlton]

Rob, I Have The Same Chuck. I Had The Same Problem On A Bowl. I Have Found That It Doesnt Work To Well On A Tenon. I Also Put A Recess In The Bottom. That Seems To Work Better.

[Rob Bourgeois]

It really wasnt that bad of a catch, that is why I am stumped.

I will try the recess. I was told( Bills DVD) that a tennon is stronger so thats why I went with it. I dont kow why but I just dont feel as comfortable with a recess compared to a tennon.

[Cecil Arnold]

I've had similar experiences using the Oneway chuck, so it isn't just a problem with Penn State. I don't have an answer, but think you might want to use a larger tenon. My Oneway stronghold with the #2 jaws will go to about 3" and I usually make them between 2 1/2" & 2 3/4" (I've gotten to the point where I can eyeball pretty well). You want to tighten it well and be sure to tighten all the keys around the chuck if you're not already doing so. One other thing you might want to consider, which will save you some time and effort, is to use the screw chuck ability you have. That is assuming that Penn still sends a screw with their chucks. I think the problem is exacerbated by the grain in the bowl bottom being parallel to the chuck face but that's only a theory.

[Gary DeWitt]

Pick up your chuck and close the jaws all the way. Open the jaws slightly, say 1/8". Measure the inside diameter. This is the diameter of the tennon you should turn on the work every time, if at all possible. The wider you have the jaws open, the less surface of the jaws will be in contact with the tennon when tightened down. This applies when you chuck into a recess as well, using the outside measurement of course.
Also, ensure your chuck is clean and lubricated, so you can tell by feel just how tight you are getting it on the work.

[Ron Ainge]

Your problem may not be the chuck at all but the type of wood you are turning. I once put a piece of aspen into the chuck and when I tightend the chuck down on it the broke off at the top of the foot. I turn some pine and I have to watch it real close because it will move in the chuck as it compresses becasue of it being so soft and the chick and the tool putting pressure on it. If you are using wood that is fairly soft check your chuck often to make sure it is tight.

[Blake McCully]

Gary is correct, the smaller the opening, the better the grip. Saying that, I've used both tenon and recess.

Now that I've said that, I have had pieces jump off both ways. I KNOW it's not the chuck's fault, but the driver. And seriously, I've had some spectacular catches without losing the piece, I've also had a minor catch and spent the afternoon chasing pieces all over the floor:( .

I know the problem is bad tool handeling. I've about given up on bowls. I have Bill G's. dvd and watched about 4 times, I've even spent a day with Bill this summer. I guess some of us just can't get the hang of it. I seem to be able to HF's without too much problem, but let me try to get into the open end of a bowl blank and well.... I just don't want to talk about it.

One thing about catches and chucks. Immediately stop the lathe at the most minor catch. Check the connection at the chuck before you go any further. If re-chucking is needed, make sure you re-chuck at the tenon end between the last marks. In other words, don't re-chuck over the original marks.

Blake "Sticking with spindles" Mc.

[Bill Stevener]

See if this helps some.
First I would suggest, as has been noted above, you stick with a more denser wood. When your tooling proficiency has reached a level of self confidence, with an air of finesse, then try a softer wood, which is more difficult to maintain a secure grip in the chuck.
Second, while developing your skills, use your tail stock. Remove all of the internal wast, as much as possible, leaving the center column for last.
I have never seen a bowl leave a lathe, when the tail stock is in place. Absolutely the best, and safest way to get started.
I have always maintained that typing is easy -- once you have been at it for six months ;) .
Have fun.
Bill.>>>>>>>>>>>>>>>:)

[Jack Savona]

Rob, you've been given some great advice. to that I'd like to add a few things.

First, if your tenon is 1/2 inch long, it might be too long. Make sure the bottom of the tenon is NOT touching the chuck jaws. That could be the problem. The outer edge of the jaws MUST be in contact with the bottom of the bowl.

Also, make sure the sides of the tenon near-perfectly match the angle of the jaws (Is it 90 degrees or angled otherwise?).

I made a template of two jaw sizes: one is just slightly larger than the jaw's smallest diameter; the other is a bit larger than that. For a roughout I use the larger template, so after any warping during drying I can re-true to the smaller diameter template. Sometimes, if the initial tenon is too small, then re-truing the tenon after drying can result in a tenon too small for the jaws (DAMHIKT).

As stated, the primary rule is: the more of the circumference of the jaws contacting the wood, the better the grip.

If I have a tenon whose stability I'm in doubt about, I liberally apply THIN CA glue to it before contact. Later on it releases just fine even without pre-applying accelerator.

This week I had the walnut tenon split at the base of a 13" bowl. I CA'd it back on using pressure from the tailstock and, with some extra re-truing of the outside, was able to finish it.

Cecil's advice about tightening all sides of the chuck is something I picked up from Bill G's video. I can even feel the need for it as I do it. Also if the wood is wet, re-tighten after a few passes.

Blake, I hate to see your confidence waning. After a quarter century teaching, I know that the lack of self-belief will demolish your ability to succeed. You CAN do it when you learn the tricks that everyone else is using (and also learn what NOT to do). Don't give up on yourself. If other can do it (especially me), so can you!!!!

[Rob Bourgeois]

Thanks I will give it a go with a denser wood. Unfortunately I only have cedar in bowl sizes pieces along with 3 or 4 pear blanks. I might have to rethink some of the Chirstmas presents. It sucks to live somwheres with no "good " trees, dang catfish and cotton farmers.

The tail stock idea is a good one and I might try that. I am just so use to not having it in my way that it will probably cause more problems. I will turn a smaller tennon also. I too am about to give up on the bowls mainly from lack of good wood. Oak and cedar are the main things and oak is hard to find before someone gets it as firewood.

/hoping the wife's job transfer comes sooner than later.

[Jim Bell]

Might also sharpen your gouges. Sometimes it's a combination of things, especially, for a new turner. There is sometimes more to a problem than is easily recognized. If an experienced turner is available try to get some seat time with him/her. For what it's worth I've had the notion of checking my underwear a time or two.:eek: Might also try shallower cuts. Take your time, the tree had yrs to become what it is and we try to change them in a few hrs. Let us know how you do,


Jim

[Rich Stewart]

Try ebay. You can get some pretty nice assortments of different kinds of wood already cut round. Not bad prices. Be careful of S&H charges. All we have around here is scrub oak and scrub pine.

[Bill Stevener]

Hi again Rob,
Another trick you may wish to try, is to turn a two step tenon from the oak you have on hand. The larger diam. the size of the foot you wish on the bowl and the tenon the size required for your chuck. Do the paper bag glue-up to the cedar, and you have a denser wood for your chuck to take a liken to. Or fasten a wast block of oak to a faceplate and then the paper bag glue-up to the cedar. There are always more than one way to skin a bowl.
Bill.>>>>>>>>>>>:)

[Rob Bourgeois]

Jim..tools were sharp, very freshly shapened. Yeah I had to check the underwear when the bowl left and ended up behind me with me ever seeing it.

Bill...I will try that 2 step tennon idea withthe next cedar bowl.

Rich...yeah I know..I just hate buying "free" wood.

I will get a time to turn on Saturday if things go right. All depends on the rocking horse assembly tomorrow.

[Gary DeWitt]

Rob, I'm not sure where you are in Mississippi, but you may be able to use craig's list:
http://losangeles.craigslist.org/about/cities.html
if there is a branch in a city near you.
I looked, and there isn't much, but there was a guy in New Orleans giving away pecan wood from a hurricane downed tree.
I check the list for LA and get free wood from someone who had to cut down a tree and is using craig's list to get rid of the wood and benefit others at the same time. Got some nice black walnut last month. The ultimate in recycling.
Another source might be tree trimming services. If you can be there when they take down a tree, they're only too happy to have someone else haul away some of the wood. Reduces their dump fee.
I had a friend take down an 80 year old olive, and I have most of the wood now, far more than I can use! I sell/give it away to members of my turning club.