Someone - Talk me down from the ledge...

[John Derbabian]

I'm fairly new to turning. Lurked here for a while now. This past winter I have turned 12 (what the loml tells me, and I kinda agree) beautiful bowls.

But the last three have left earthly bounds and entered the stratosphere at a very rapid rate, only to, upon re-entry, hit something and shatter. This has left me to wonder what the lathe would look like as some sort of planter or even a mailbox stand.

Can't quite figure out what the heck is going on. I only know that when I get to working on the inside, I get a catch that brings an early end to the last three expensive exotic blanks. All three different types of wood. Two were green, and one was fairly dry. I'm using a fingernail grind bowl gouge.

If someone - anyone has some encouraging words, I like to hear them before the lathe becomes a permanent reef in a local lake. :mad:

signed: hopeless in Harrison Twp...

[Malcolm Tibbetts]

John, at least you've still got a sense of humor. Best advice that I can give you is to find a local club and hook up with an experienced turner. Clubs are a great resource for new turners. Secondly, I'd save the exotic, expensive stuff until you've acquired more experience and skill. Get some cheaper (hopefully free) wood and practice, practice, practice.

[Jim Becker]

Based on your description of when this is occurring, I agree with Malcolm...some mentoring is a good idea so someone experienced can watch what you are doing. Catches happen because the tool is not properly oriented to the spin of the wood. When you use a side-grind gouge on the inside of a bowl, there are some very specific rotational movements that you need to do as you make your way through the cut. If you do it right, you'll have a wonderful, smooth cut surface all the way from the rim to the bottom center of the piece. If you don't, you'll be an honorary member of the NASA launch team... ;)

[Dennis Peacock]

Alright John......it's time for you to post some pics of the results of the flying bowls so I can see if I can tell what's going on.

One guess is tool rest is too far away and allowing the gouge to get ugly on ya. Maybe too heavy of a cut. Either way, a catch is a problem with tool presentation or tool control if the tool rest is reasonably close to the inside of the bowl being turned.

You can try using a 1" dowel to pin the bowl to the chuck via the tailstock until most of your material is gone except for the very bottom of the bowl blank. I've had to do this several times to best prevent such a "launching".

Keep it up.....we all learn from mistakes and some of us...it just took longer is all. :o :)

[Steve Schlumpf]

John - I agree with Malcolm and Jim - find a local club and it will save you a lot of time and frustration. Meanwhile - if you have some turning wood (that is not exotic) that you can practice on - when you get towards the bottom of the bowl where you have been experiencing catches - change over to a round scraper. Keep the scraper on the centerline and use light cuts. Make sure the scraper is sharp and you should see curls coming off of it - and no more problems with finishing your bowl.

[Lee DeRaud]

Now that the weather's getting better, you might also try moving the lathe out to the middle of the back yard so the wayward turnings don't have anything nearby to hit upon reentry. Make sure you're not under the patio cover or any overhanging tree limbs, as they can render the trajectory somewhat unpredictable. Worst case, we can generate another thread on the proper gauge extension cord for outdoor lathe usage.

(Anybody know offhand what the record is for "hang-time"?)

[John Derbabian]

Thanx for all the reply's guys. I'll post some pix when I can get the nerve up to re-enter the launching pad (hopefully later today). I like the backyard idea. Heck, at the rate they're coming off, I might get the neighbor next door to me to come over and practice a little 'skeet' shooting! :D

[Ken Fitzgerald]

(Anybody know offhand what the record is for "hang-time"?)

Lee does "hang-time" include the time you spend hunting for it after it launches or just the amount of time it's in the air?.....also does hang-time include the bank-shot times ...mine seem to hit the wall behind the lathe...go oblique to the ceiling and then disappear behind me. Would you clarify the definition of hang-time please?:rolleyes:

[Lee DeRaud]

Lee does "hang-time" include the time you spend hunting for it after it launches or just the amount of time it's in the air?Normally it only includes the time until the piece first returns to its original altitude. OTOH, if you're going for a maximum-range record (best attempted outdoors), you do get to include the final roll-out.

.....also does hang-time include the bank-shot times ...mine seem to hit the wall behind the lathe...go oblique to the ceiling and then disappear behind me.Remember, just as in real estate, location is everything. If you place your lathe properly, the sequence is launch-wall-ceiling-wall-tablesaw-grinder, culminating in touchdown on the lathe bed, ready for rechucking. ("We are trained professionals: do not attempt this at home.")

[Cyril Griesbach]

John, without knowing much more about your process/system I'm going to assume the problems are in your mounting of the blanks. Here are some possible causes.

1. You have your gouge too far over the tool rest. Adjust the tool rest frequently to keep it as close to the cut as designs allow.

2. If you are using a chuck and expanding it into a recess and the walls of the recess could be failing. Change to a tennon and make sure that you have a good flat at the bottom of the tennon for the jaws of the chuck to seat against.

3. Your tennon or recess is in sap wood which does not usually have the strength of heartwood.

4. Since you're new to turning you may be trying to "save" as much wood as possible. Especially if you have paid lots of money for those exotic blanks. Now maybe your recess/tennon is quite small and inadequate because you're trying to "save" more wood. A poor form in fantastic wood is still a poor form. A fantastic form in plain wood is still a fantastic form. The best (and even just plain good) turners always sacrifice wood for form.

I hope this helps some and isn't too late for you to see it. Please don't give up on the turning. There is lots of help available and most of it's free and quite often it is actually worth more than you paid for it.

[Curt Fuller]

A good demo at a club or with someone over your shoulder to help point out what you're doing right or wrong is the best thing for learning. But until you can get that this might help. When you're working inside of a bowl with a gouge, the catches are magnified by the fact that the centrifigal force of the spinning wood pushes the gouge deeper into the wood as the catch is taking place (in a split second) which causes the launch to occur. It takes practice mostly but what you're trying to do is keep a small portion of the cutting edge of the tool in contact with the wood at the same time as moving the tool either in towards the center or from the center outwards, depending on whether it's a push or pull cut you're making. To do it requires a lot of swing at the end of the handle. If you don't keep the tool moving with the contour of the surface of the wood then suddenly much more of the cutting edge starts biting into the wood and it's then that the catch takes place. It all happens so quickly that it's over in a split second and that beautiful piece of wood is airborn. Like I said, it takes practice, but that's the general idea.

BTW, you said you're using a "Toenail" grind on your gouge. I tend to cut my toenails off pretty straight while my finger nails are more curved. If what you meant as toenail is a straight across grind it might help to grind back the edges of your gouge more like a fingernail grind. Google "ellsworth grind" and you'll see a good example.

[Ken Fitzgerald]

Often the cause if you are using a chuck is one of a couple:

1. If you are using a tenon, the shoulder of the bowl where it meets the tenon isn't square and flat. The force is actually supported on the shoulder of the bowl.

2. If you are using a tenon, the tenon is too long and is bottoming out on the jaws or body of the chuck. That should never happen......the chuck grasps the tenon but the outer surface of the jaws rest on the bowl and provides the support for most of the force.

[George Morris]

John where do you live? Check on the AAW web site for a local club. George

[Joe Chritz]

Member of NASA launch club x2 and counting.

At least you have one to completion. It's getting there for me slowly.

Joe

[John Derbabian]

Thanx again for all the great suggestions. There are a great bunch of guys here. I think my tenon is good. Not too long - not too short. On the last piece (that I now refer to as Sputnik III), when the catch occurred, the tenon broke off and lift off was achieved. I have attached two pix although they may be difficult to really see the issue. It always seems like I get it to the point where it's pretty much done and ready for the DNA, then one final touch, one little area I want to fix a little, and then the burners are lit. I had been using a rounded scraper, but I was getting catches with that too and I was told at the local Woodcraft that I should be using a fingernail gouge. I know with the scraper that you need to be on the centerline. Is that the tool rest or the pitch of the tool downward to the centerline?

By the way, I did mean fingernail gouge in the first thread - must have been cleaning my toenails when i was typing... :D

http://www.redskyguideservice.com/sm2.jpg

http://www.redskyguideservice.com/sm1.jpg

[Curt Fuller]

Those pics look just like the classic catch that I'm sure number in the trillions if you counted all of them that we have all had. It's really hard to explain without being able to show in a hands on sort of way. It has to do with so many things including the way you're holding the tool, the way the tool is ground, how sharp the tool is, the tool rest height which determines how the tool addresses the wood, etc etc. But mostly it's practice and some hands on help that will benefit you the most. If you can't get to a club for a demo add your location to your profile and someone will probably be glad to give you a little saturday morning tutoring.

[Jim Underwood]

Looks like the topmost wing on the gouge got a little sideways, and burrowed in..... Gotta keep that flute heeled over in the direction of the cut.

I lean toward the advice the doctor gave when a guy said:
"Doc, it hurts when I do this..."

Doc says:

"Don't do that."

:D

[John Derbabian]

Ok, so If I understand you Jim, the first picture below is what happened. The second pic is how it should be held for a outside in cut?

BTW: I don't use my thumb for a tool rest. Just trying to hold it all together and take the shot... (hehehehe)

http://www.redskyguideservice.com/sm3.jpg




http://www.redskyguideservice.com/sm4.jpg

[Andy Hoyt]

I'll add another comment to the mix - just to increase your confusion factor.

That wood looks suspiciously like some infamous spalted hickory I had a while back. Darn stuff would exploderize on me and/or shear off at the tenon just by looking at it cross-eyed.

And if this is the case with your flight training, guess what? You can blame the wood.

[Jim Underwood]

That's more or less it. Once you get let that wing get over to the left, it's pretty much takes over and dives in. You could probably re-enact it by turning the bowl by hand and watching what the tool does in certain positions.

You can get away with it being almost upright, but if you let that wing catch it's all over...

The trick is to have the bevel rubbing the whole time, and I haven't yet figure out exactly what part is rubbing the bevel, and at what "O-Clock" it does the best. I just know I don't want it at ll:59 - because that's when it all hits the floor, the walls, the ceiling, and a few places in between.:D

[Alex Cam]

John,

If you can make a weekend trip up to Traverse City, take Lyle Jamieson's 2 day hands on class. Best money you'll ever spend.

Alex

[Jim Becker]

Yes, if you rotate the gouge too far to the left as in the first picture..."bang". You do want it pretty upright after the start of the cut...I will get it touching on the bevel rotated slightly right and then bring it back up very slowly. As you sweep through, you'll begin to rotate to the right to keep the bevel rubbing and keep the cut very fine to the center. It's a gentle motion that you can actually do with one hand with practice. (In fact, in David Ellsworth's 3 day seminar, that's one of the exercises one does...for about a half hour or so! LOL) You also move your body through the cut rather than cranking the gouge with your hands.

[John Derbabian]

ANDY: Your close - spalted Maple (very wet). I had another blank just like it that turned out awesome (before I got my flight wings).

JIM: I think I know what I'm doing (one of things) wrong now - not keeping the tool rolled over as I move inward.

ALEX: Is there a web site for Lyle's course?