Turning A Large Bowl

[crokett]

I have the opportunity on Friday to get a Redbud stump that is about 15" in dia. It is still alive so would need to be roughed, then let to dry. Class has a lathe big enough to do the roughing, and I have an instructor to help, but my lathe only has a 12" swing. Can I rig a tool rest and turn on the other side of my head stock after the blank dries?

 

[Mark Stewart]

That depends on the lathe you have. Mine Ihas a rail just for that purpose. Good luck with the stump. a work in progress pic would be nice as well.

Thanks Mark

 

[Sully]

Yes. But be aware that when turning on the outboard you will be cutting goofy-handed compared to cutting on the inboard side, i.e. the blank will be spinning clockwise on the inboard side.

Of course if your lathe reverses, and you have a way of locking the chuck/faceplate to the spindle*, you can just spin it CCW on the outboard side as well. Edit to add that the threads on the outboard spindle are also likely to be LH versus the RH of the inboard.

J

*Emphasis added for safety. You don't want a large blank unscrewing itself off and coming at you.

 

[crokett]

Lathe is a delta 46-465. It doesn't reverse AFIK. The threads on the left side of the spindle are left-handed. The spindle nut comes off clockwise instead of counterclockwise. I think that means face plates, chucks, etc would all get jammed on tighter when cutting, no?

 

[Sully]

The threads on the left side of the spindle are left-handed. The spindle nut comes off clockwise instead of counterclockwise. I think that means face plates, chucks, etc would all get jammed on tighter when cutting, no?

Correct. My safety comment is only relevant if you were to reverse the direction the lathe turns. You will need LH thread faceplates, chucks, etc. You may also need LH bowl scrapers, etc.

 

[crokett]

You will need LH thread faceplates, chucks, etc. .

Hmm... didn't think about that part. Will talk to my dad about possibly making some kind of adapter to use my existing tools, but that would put the piece way out beyond the end of the spindle. I wonder if oneway sells a replacement center nut for my chuck to put it on left-hand threads.

 

[crokett]

I did some checking. Called Oneway and he said they sell an adapter to screw onto left-hand threads but that mine already should. I checked and it does. :wsmile: So next question... in class the largest we can turn is 15". Assuming I were to do that, the tenon or mortise for the chuck would warp when the bowl dries, no? I expect the way you fix that is after it dries to put it back between centers to get the tenon round again, correct? Problem is, I won't have a tail stock to put it back between centers. If I were to mark the center of the bowl on the bottom with a very small mortise, then glue a tenon on after it dries with a locator pin, would that be enough to turn the tenon/mortise round on the bowl so I could rechuck it?

 

[woodArtz]

I used to have this issue with my old Jet 1236... The way I got around not having a center available in the outboard mode is that I left a tenon in the center of the inside of the roughed bowl. That way I could rechuck the inside, tune up the bottom tenon, then reverse to complete the hollowing. Not optimal, but doable.
MTCW

I did some checking. Called Oneway and he said they sell an adapter to screw onto left-hand threads but that mine already should. I checked and it does. :wsmile: So next question... in class the largest we can turn is 15". Assuming I were to do that, the tenon or mortise for the chuck would warp when the bowl dries, no? I expect the way you fix that is after it dries to put it back between centers to get the tenon round again, correct? Problem is, I won't have a tail stock to put it back between centers. If I were to mark the center of the bowl on the bottom with a very small mortise, then glue a tenon on after it dries with a locator pin, would that be enough to turn the tenon/mortise round on the bowl so I could rechuck it?

 

[crokett]

Huh. Didn't think of that. I am also wondering if a big donut chuck would also work. I could put the bowl in that and put it in my chuck. I would need one anyway to do the final finishing on the bottom