launching - help needed?

[Dan Cannon]

Hi all,
I need help again. I plan on asking at the next turning meeting and finding someone who can take a look at my technique, but I'm impatient and thought I'd get anyone's ideas here in the meantime.

I was practicing some cuts and shapes on some semi-wet dogwood from my yard (tree died naturally 1 year ago). I was just trying to make a mushroom from one of the limbs, full section, about 4" in diameter. Everything went well until I got to the top, where I was cutting on end grain trying to round it out. I simply could not avoid catches in this particular area, and have launched this piece out of the chuck at least 5 times. the end seems VERY irregular while it's cutting and almost pulls the tool into it. I even used the Easy Finisher (which I'm trying to avoid until I learn the traditional tools first) with a really light touch. Still launched it. I'm new at this, and don't know what to expect, but this seems excessive in the catch category.

Is cutting end grain on wet(ish) wood usually this difficult/dangerous? Just trying to figure out if it's the wood, the tools or the turner.

Thanks in advance for any advice!...
Dan

[Karl Card]

From what I have been told it can be those conditions and also the angle or cut on the tool itself.

[John Keeton]

Dan, are you cutting "downhill?" In other words, are you trying to pull a cut with the grain or against it? On a branch, if you are cutting from the end of the piece, back toward the middle, you would be cutting against the grain and greatly increasing the chances of a catch. Pics would help with a diagnosis.

[Dennis Ford]

There is a lot of force being put on the tenon when you are cutting at the free end, this tends to cause deflection which will cause a catch. In other words; any problems are self multiplying. Try making a similar cut with a shorter piece in the chuck, once you get the technique down you can try it with longer pieces.

[Mike Peace]

Without pictures it is difficult to provide a full diagnosis. Could be you don't have a good tenon with clean 90 degree shoulder. Perhaps you are crushing the tenon by over tightening the jaws which can lead to failure. Could be you simply have too long a piece for the size chuck jaws?

I use tail stock support as long as possible. Cut the face grain down to a small nib with TS support and then remove the tail stock and take very light, fine cuts to remove the nib. Or even cut the nib off with a saw and sand smooth.

Good luck as you climb the learning curve!

[Dan Cannon]

Thanks for the quick replies...here are a couple photos I just took. Keep in mind, it was NOT cracked while I was turning it, that happened since then. You can see the latest catch in both shots. That last catch was with the tailstock in place, you can see where it tore over to a new hole when it caught. That's when I called it a night...This was done with the Easy Finisher and I promise it was a light touch, not nearly as deep as that makes it look. At least not until it seemingly "pulled" in and caught. Please ignore the shapes on the end, at this point I was just trying tools and testing cuts.

John - I'll have to give it some thought, I think I was going both uphill and downhill.
Mike - The tenon is about 1.75" diameter, the main piece is about 3.5" diameter at it's largest point.

Thanks again,

Dan

[Tom Sherman]

Dan looking at the first picture, it looks like you have a chuck with beveled jaws if the bevel is on the inside of the jaws also you need a bevel on your tenon to match. When you cut on the end like that the technique is to start your cut then lift your handle while rolling the tool into the work at the same time. Light cuts at first till you get the hang of it.

[David DeCristoforo]

First of all, I would use larger jaws on the chuck to grip the entire bottom of the blank instead of trying to grab a small tenon. Secondly, I would use the tailstock center, at least for the roughing process. That piece is pretty long and a catch on the end with only a small tenon held in the jaws... well "launching" is what you get!

[Michael James]

Personally, I'd use a tailstock, as mentioned, and make sure you tools are sharp, sharp, sharp!
mj

[John Keeton]

Given the pics, I would say you had too much flex in the piece. I wouldn't try this without the tailpiece in place, and if I tried to hollow it, I would have to use a steady rest.

[Aaron Wingert]

Just to be clear also, you should be turning from left to right on the mushroom end of this piece. Turning downhill that is. If you go from the right to left "uphill" you're more apt to get a catch. I'd also use the tailstock until the very last minute, and take very light shearing cuts to get rid of the tailstock indentation.

Assuming you're new to turning I'd suggest getting some 2x2 stock at the lumberyard. Poplar is cheap and great for turning, and maple works well also. Heck, even short pieces of clear pine 2x2 are good for practice. Turn beads, use the parting tool, rough things out...Learn where you're going to have problems.

Cutting a piece of a tree limb could be causing problems because of the pith in the middle.

Sounds like you're going to get some expert instruction at the upcoming meeting and that is good. Bad habits are easy to learn and hard to break, and when many of us started out we had some bad habits!

Sharp tools? Like really/properly sharp? Your tool presentation to the workpiece is everything. I'm confident with some good instruction you'll learn what you're doing wrong in no time.

[Bill Bulloch]

Dan, I do a lot of pear shaped, gourd shaped and round bottoms for the ornamental bird houses I make. I always use the Tailstock until the peice is shaped and sanded. This will leave a little "Tit" on the piece that you can carefully cut or sand away after you have finished and are satisfied with the shape.

[Jim Underwood]

Looks like an unsupported cut caused by cutting "uphill".

Any time the tool is not supported by the toolrest directly under the point at which the tool is cutting, you'll get a catch. I tend to think of it as a balancing act like a teeter-totter. Any time the down force of the wood turning overcomes the leverage you have on the tool... down it goes.

To test out what happened, turn the piece by hand, and re-create the way you had the tool approaching the wood. See if it doesn't tend to dig in....

[David E Keller]

I thought you needed help getting pieces to launch when I read the title... I consider myself to be a regional expert on getting wood to fly. As for keeping it on the lathe, I'm not as helpful.

As previously mentioned, I tend to make that end curve with a push cut from left to right as you are facing the piece.