Big Bowls

[metalspinner]

I just finished my biggest bowl to date.  And realized that bigger is scarier. :D

This bowl ended up 18" diameter x 6" deep.  The blank was fairly dry, so I just turned this whole thing in one sitting.  It took about 5 hours. The first coat of oil went on at midnight last night.   

A bowl half this size in each dimension would have taken just a quarter of the time.  I realized some different techniques and tools are needed for this size work.  I'm just not exactly sure what those would be.   Anyone care to share ideas?


I didn't think to take pics along the way.  But here it is after the oil and wax...







Chucked up to turn and finish the foot...











In its final resting spot???  I may need to build a bigger table.







With a pocket knife for scale...





This first biggun' wet my appetite for more. :  I can squeeze a 24" blank on the lathe as it's currently designed.  I will need to make up a longer and shaped tool rest to do it though.  The lathe might be able to be reconfigured with the head stock at the end of the ways.  Then, the ceiling is the limit - literally. ;D

[woodsteach]

WOW!!!

Can you explain that "holder" that looks like it makes a big bowl sandwich.  How is it attached to the headstock? 

So what does the blank typically look like when you start it?  I've never turned from solid stock only glue ups.

woodsteach

[Radar67]

That's a great looking bowl. What kind of spalted wood is that?

[metalspinner]

Teach,
This particular piece came froma large maple stump that I slabbed with the chainsaw.  So it was relatively uniform in thickness.  Hefting it up onto the bandsaw table was quite a workout.  A large auxillery table for the saw is in order.

That holder is just screwed right onto the spindle.  On my normal lathe, I have a smaller one permantly mounted to a face plate.  The back disc and donut have matching holes for the carriage bolts.  Several donuts will need to be made to accomodate different bowl sizes and shapes.  On the small lathe, four different size donuts gets me through most bowls.  I'll get a couple of pics tomorrow...

Radar,
It's a soft maple.  Not sure of the flavor, though.  Silver maple would be my guess as that's a very popular yard tree around here.  It grows into huge logs, too.  Which makes for some big bowl blanks. ;)

[Don K]

Fine work, Chris.

Don

[WDH]

What is the grain orientation on the blank?  How does the longitudinal grain and the end grain relate?  Another way to ask.......looking down into the bowl at the knife, where is the end grain or cross-sectional part?

That is beautiful!

[Burlkraft]

Nice bowl Chris  ;D  ;D  ;D
Spalted maple is one of my favorites and that is a dandy  8)  8)  8)

I use the same tools as I would to turn a smaller bowl only in a bigger size. I have a few 5/8 bowl
gouges with a revised Ellsworth grind on them that work great for most of the turning.
I made a couple large scrapers to go along with them.
I also have a Texas Hollowing Tool that is a Sorby that I picked up on sale at our Woodcraft store.
They had it in the store for a long time. It's almost 4 foot long     

I like turning bigger stuff.  Once ya get started it's hard to turn small stuff again.
The biggest I've done is a 42" tabletop and that was a challenge.
Show us some more big work  ;D  ;D  ;D

[metalspinner]

Danny,
It's a flat sawn blank.  The grain is running near parallel with the pocket knife.  The open end of the bowl is nearer the center of the tree.  I didn't make a concious choice with that orientation.  The blank was just facing that direction when I stuck it with the compass. :

Here is a good shot of the end grain.  Notice the bird peck around one of the growth rings.





The large blank had a couple of cracks.  They were filled during turning with CA and dust.  Time will tell if they open up. :-\

I use the same tools as I would to turn a smaller bowl only in a bigger size.

I believe I need better tool rest support to use regular sized tools.  Right now I have just the straight rest which really puts the tools hanging way off the rest.  Too much chatter potential and loss of control.

Burlkraft,
How about a pic of that grind you mentioned?

[Lud]

Nice job , Chris.  I like the challenge of the big ones too and made some tools to extend my leverage.




but the fact is there's a range of size that folks will use most often.  Look at the pottery booths at a craft show. Six inches up to ten are the sizes that get used.  Big stuff is artistic but is it functional?

Really like that big round rim's look and I think my hand might like the feel,  but could you pour out of it?

With spalted maple, I'll often do a wire burn to define the foot, waist or rim.  I like the way the black lines in the spalting get tied together by the burn.

[WDH]

The bird peck gives it special character.  You can't get special character at the store!

[turningfool]

great job! nice looking bowl..i have turned a few around 20" and they ARE a challenge..with the exception that mine are strictly mounted on the face plate and run outboard as i can only do 16" over the bed.variable speed is the only way to go with the bigguns that cant be mounted over the bed..will try to scrounge of some pics,but think they've been deleted over time...once again..great job metal spinner 8)..you know you're getting older when its harder to mount turning blanks over 150 pounds by yourself ;D

[Raider Bill]

Another great job Chris!

[treecyclers]

I just finished my biggest bowl to date.  And realized that bigger is scarier. :D

This bowl ended up 18" diameter x 6" deep.  The blank was fairly dry, so I just turned this whole thing in one sitting.  It took about 5 hours. The first coat of oil went on at midnight last night.   

A bowl half this size in each dimension would have taken just a quarter of the time.  I realized some different techniques and tools are needed for this size work.  I'm just not exactly sure what those would be.   Anyone care to share ideas?

Turning large vessels takes a tremendous amount of thought insofar as determining shape, depth, and tooling.
Hollowing tools are often useful on deeper items as well as for hollowing a vase.
Scrapers are what I have used on larger bowls for final hollowing, as they cut less material and leave a nicer finish.
Be aware of your speed, too. The further you go from the center of the turning axis, the surface speed increases exponentially. You may be turning at 500 RPM, but your surface speed on an 18" diameter bowl could be 500MPH!
The largest item I ever turned was a 30" platter from a pine wheel I cut off a log.
That was really neat to turn, and I had a hard time getting the lathe to turn slow enough to get clean cuts on the outside edges instead of tearing and chattering.
I grind my bowl gouge extremely aggressive too. It gives me a nice lip to use when hollowing, and offers me a couple different options for using it than if it were conventionally ground. It's also very difficult for a novice to use. One gent tried it when I wasn't looking, and took one in the kisser. Cost him a tooth for borrowing my tool without permission, and I had nothing to do with it.
Some lathes have a variable speed that allows you to get way down low on rotation, specifically for turning monster items.
We all know that 48" diameter stock is rare unless we laminate it, but there are a few lathes available that can handle turning outboard that large. Reversible motors are a huge help too. Turning outboard on a conventional lathe means that you'll be turning in reverse, and you'll have to really think about what you're doing, just like when you were learning turning.
Oneway offers a few exceptional lathes, and yes, I know they're made in Canada.
Gotta give credit where credit is due, right?