Read the directions stupid!

[Steve Eure]

It's a man thing, right?
For starters, I'm new to turning. Have watch videos and read all I could find on the subject and have asked a few questions here on SMC.
Today I turned my first bowl and it was shaping up nicely. I put on my Nova cole jaws to finish the bottom. While cutting off the tenon, the bowl launched out of the jaws, hit my fluorescent light which exploded into a million and one pieces and pretty much made a mess of the shop.
Fortunately I was no worse for wear. My face shield blocked any glass from hitting me.
The reason for the above title is because I failed to read all of the instructions on the jaws or I plumb forgot what I read. First off, the jaws clearly state 600 RPM's. I was running at a little over 900. Number 2, the bowl has straight sides and did not have a negative flair on the lip.
I now know that some of you turners will use a donut type chuck on some other type of compression clamp to solve this problem.
I was very fortunate that the bowl was not damaged in any way that I can see. There was no catch to cause this, maybe just the two reasons I stated above.
I wound up putting my tool rest close to the bottom of the bowl and also brought my tailstock in to prevent it was launching again.
LESSON LEARNED!:eek:

[Robert Edington]

I think you'll find that 600rpm restriction is just boiler plate for lawyers. Cole jaws are more for centering than holding. You risk damage or otherwise marring your bowl if you over tighten the jaws. Alot of folks use Saran wrap, tape, straps to "hold" the bowl while turning. Light cuts with sharp tools are a necessity. I quit using them once I learned to trust hot melt glue. I have a 19" disk of MDF on a face plate. Four or five dabs on the rim does great. I reverse chuck it to get the bowl centered.
RP

[John K Jordan]

It's a man thing, right?


Yikes, I'm glad you were not injured!!

Even if you kept it at 600 rpm it could have come off, of course, from the shape as you mention even with light cuts. If the lip does turn in you can sometimes better grab it in the expansion mode of the jaws. If the lip is thin it is easier to crack it but you can wrap it with tape before expanding.

Years ago I started doing this with Cole jaws, jam chucks, etc: I loop multiple strips of tape around the bowl from one part of the jaws/chuck leaving the base that I want to turn clear. Then I bring up the tailstock (as you mentioned) to press against the middle of the base while turning most of the foot, then back off the tailstock and nibble away at the remaining nub using cuts that push straight towards the headstock (no side forces). Then I use a small hand scraper to make the bottom perfect. (or just pare down the nub with a chisel or knife and smooth by hand)

BTW, this is my favorite live center for nibbling away at the base and many other things: https://www.amazon.com/gp/product/B0064JIZGC
I turn a short Morse taper on a short piece of wood which will fit securely in the live center, then press on the bottom of the bowl with that piece of wood instead of a metal center. Then as I cut closer to the center I can even cut into the piece of wood without hitting metal. (I keep a variety of these little wood "centers" in a drawer so I don't have to stop and make one when turning.)

Also, this is my most-used tape at the lathe. Unlike most masking tape, it is stronger and has a much better adhesive (nothing like painter's tape):
https://www.amazon.com/gp/product/B00004Z4AY
Nylon reinforced strapping tape is also very good but is probably overkill for this application.

Oh, if it is a "man thing" I must not be much of a man. :) I'm a compulsive manual and instruction reader. It's so bad that after some use I read the instructions AGAIN to make sure I didn't miss or forget something. I do all the tutorials provided with complex software, too. [gasp!]

JKJ

[Barry McFadden]

I always use tape when I'm turning off the bottoms of a bowl or vase even if there is a good lip for the jaws to grip onto. I usually use 2" Gorilla Tape which is VERY sticky so I put a layer of 2" painters tape on first so the finish won't be affected. This picture is using Duct tape because I was out of Gorilla Tape at the time. I have had a tall vase come loose on me but with the tape it's no problem to stop the lathe and get things sorted out.

378901

[bob svoboda]

Good advice. In addition, I shielded my fluorescent lights with a wire grid similar to chicken wire. Has saved my tubes several times.

[John Beaver]

With cole jaws you do not have a positive tenon and since you are holding the rim of the vessel, there is likely a good chance of flex happening. The torque of turning the tenon is quite a bit of power and can easily pull a bowl out of the cole jaws.
I strongly recommend using the tail stock to keep the bowl in the cole jaws until the very last nib, then turn the speed down and take light cuts.

[Phil Anderson]

Hi Steve!
When I first started turning bowls, I too found out the Cole jaws are not all they are cracked up to be. You don't want their need for a particular kind of rim dictating what you turn. And, they just aren't all that secure, anyway. I finally found what works for me and I use it every time, whether it's a tenon or a recess I need to remove. I thought what I had learned might help others so I made a couple videos. You can find the playlist of two videos, here: https://www.youtube.com/playlist?list=PLX4bPjUe1Imerk8gCP00xHujEv-ExSpnT

[Kenneth Hertzog]

I use shatter shield bulbs in all florescent fixtures in the garage
for the reason stated above and saves a whole lot of cleanup time
Ken

[JohnC Lucas]

I use the tailstock until the last few cuts. You don't mention what tool you use to turn. Cutting tools do a better job of not pulling the bowl out if you don't force the cut. I normally recommend gliding or floating the bevel. You normally want as little pressure on the bevel as you can get. When turning the bottoms I do use more pressure so the bevel pushes the bowl against the chuck. What you don't want to do is force the cut. this is pressure pushing toward the center. Relax and let the tool cut so there is very little sideways pressure. Last but not least. There have been a few posts over the years where someone has had the jaws break off when turning at too high an rpm. It is simply not necessary to turn fast. You could turn that bottom at 200 rpm just fine, it will simply take long to make each pass.

[Lamar Wright]

Same thing happened to me Steve two days ago and I was turning only 525 RPM. I taking the tenon off the foot of the bowl and when the bowl came off it broke in several pieces. I'll never use a cole jaw for nothing but only applying finish. As you said" lesson learned".

[Eric Marsh]

Anybody tried these?

https://youtu.be/HHyfojnw0ZY

[Brice Rogers]

Eric, thanks for posting that. It is very unique and interesting.

[John K Jordan]

Yes, interesting. Big enough to swing a tool inside would be more useful to me.

JKJ