Deep bowl techniques?

[Charlie Harley]

Are there special techniques for turning a bowl where the depth approaches the diameter or maybe even goes beyond?

My tool rest is somewhat limited in how far it can go inside the bowl and the gouge starts getting squirrely. I've had some success using a scraper in a deep bowl but that has its limitations too.

Any help is much appreciated.

Yes, I've joined the AAW and this fall I'll start attending the Ohio Valley Woodturners Guild meetings. They seem like nice folks, and I've always said that the best instruction manual is a mentor.

 

[dkulze]

Two methods.

First, specialized tool rests that will go further into the bowl.

Second, various partially or fully stabilized hollowing rigs.

Just what size are we talking about here?

Dietrich

 

[john lucas]

I think a tool rest that extends further into the bowl to help support the gouge and a gouge with a steeper angle on the tip so you can reach in and still be on the bevel. I have one that is sharpened almost 80 degrees.
For really deep bowls (more like vases) I use a captured bar rig like the Jamieson system.

 

[Charlie Harley]

It's a salad serving bowl about 10" in diameter by 8" deep.

 

[hockenbery]

Charlie,

Once the depth gets a bit more than 1/2 the diameter some considerations need to be taken in order to ride the bevel and get a clean cut.

With a typical bowl gouge the bevel angel will be in the 45-60 degree range.
As you hollow out the bowl you will find the gouge will hit the rim of the bowl and not allow the bevel to ride when it is hollowed to a depth a bit over half the diameter. When turning deeper the tool must come off the bevel and most often folks get a sort of washboard effect on the bottom. The tool wants to follow the bevel and cut deeper into the wood the turner corrects the cut and the tool immeadiatly cuts deeper. This constant correction and the tool doing what it want to create the ridges along the bottom.

For a really deep bowl you may need to grind a bevel of 80 degrees, like John said.

If you use a side ground bowl gouge and have mastered the shear cut insdie the bowl this will buy you another inch or so in depth an still allow the bevel to ride.

Also grinding the heel of the bevel away will buy you another inch or two and allow you to ride the bevel to the bottom of the bowl.

Using a gouge with either the Ellsworth or the O'neill grind and the heel relieved an 8" deep, 10" diameter bowl can be hollowed to the bottom riding the bevel.


happy Turning,
AL

 

[dkulze]

First, I have to wonder what tool you're using for the inside. If a bowl gouge with a tool rest longer than 6", you shouldn't have major problems if you're able to ride the bevel well with your cut. If you're not sure what that means, then you might want to snag someone from your nearest AAW club chapter and do a little hands on work.

Second, what you want is a curved tool rest that sticks out well from the banjo. You can buy them online, at Woodcraft or other higher end woodworking stores, or can have your local ironmonger whoop you up one.

Dietrich

 

[TurningDog]

my choice in this instance would be to go to the hollowing rig. and barring a hollowing rig go to a very thick half round or fully round scraper.

 

[DeanGThomas]

This shape, A Different Solution

The other thing you might want to consider is the use of a hook tool (shaped a lot like the ? in the header). The sort that Alan Lacer talks about on his website (http://www.alanlacer.com/articles/basic_hook_tool.html). They are available commercially, too. Send me a PM or email if you want a specific site. Alan provides all the instructions you could ask for, IMHO, for construction.

Because the hook is roughly semi-circular, you have LOTS of angles of attack, and because the bevel is not long, you get to rub bevel at all those angles of attack as well. It takes a bit of getting used to (as do most tools; witness the skew!), but once you get the hang of it, you can cut smoothly and make fine adjustments with the tool. Good stuff.

 

[Mark Mandell]

Charley,

Since nobody else has, I'll comment that 10" dia by 8+" depth will not be much use as a salad bowl; much too deep for the width. Design considerations to the side, salad needs to loft in the bowl ("tossed salad") so packing that much depth will make things hard for the cook and the eaters. Consider less depth - max 5" for a 10" bowl.

Much easier to turn and finish as well.

 

[Hugh]

I think I am with Turning Dog on this one. I would use my hollowing outfit. I use a Stewart handle and either my home made straight scraper, or the "Hooker" tool made by Stewart. It is 3/4" dia. rod and will reach out off the tool rest a bit. It sounds like you are making a hollow vessel with a wide opening anyway.
Hugh

 

[John Nicholas]

Hook Tool

The other thing you might want to consider is the use of a hook tool (shaped a lot like the ? in the header).

I've always heard that ring and hook tools are designed for cutting endgrain, not face grain. Since most bowls are turned for face grain, I've never considered one for a bowl.

Is there some new info out there about using them with face grain?

John

 

[TurningDog]

I've always heard that ring and hook tools are designed for cutting endgrain, not face grain. Since most bowls are turned for face grain, I've never considered one for a bowl.

Is there some new info out there about using them with face grain?

John

you can use them on face grain, they just have to be used at slightly different angles and don't necessarily work as well as they do on end grain.

 

[MichaelMouse]

First, watch your knuckles when working a deep bowl. It's almost as tough on them as an interrupted-edge turning. Those burn/cut combinations take a long time to heal, too.

I second the dog on salad bowl dimension. What you are working with is a popcorn bowl. Leave the bottom a bit thick for insulation, give a bit of a grip for greasy finger passing, and don't use a surface finish that might be affected by the heat of the unpopped kernals.

I don't use the edge of a bowl gouge for anything but hogging, preferring to gain the firm support of the rest and the stability of a constant angle bevel provided by the forged pattern gouge. Only drawback is keeping the proper angle around the corner to the button on the bottom. Sometimes you have to go to a shear scrape angle of attack. I run this rest, which reaches in almost seven inches. Sometimes it's tough to find room underneath, because he's designed as a bi-directional rest, but otherwise no drawback. Where he might need some help, or where the opening might be so narrow only a bar rest will do, there's the extender.

As to hook or ring tools being used on face grain, they're well capable, but they work below centerline, and you lever the rest to keep control because of the strange angle. You can do the same with your swept-wing bowl gouge if you like.

 

[Ron Sardo]

Charley,

Since nobody else has, I'll comment that 10" dia by 8+" depth will not be much use as a salad bowl; much too deep for the width. Design considerations to the side, salad needs to loft in the bowl ("tossed salad") so packing that much depth will make things hard for the cook and the eaters. Consider less depth - max 5" for a 10" bowl.

Much easier to turn and finish as well.

I call deep bowls "Popcorn Bowls"

 

[pyrocasto]

First, watch your knuckles when working a deep bowl. It's almost as tough on them as an interrupted-edge turning. Those burn/cut combinations take a long time to heal, too.

I second the dog on salad bowl dimension. What you are working with is a popcorn bowl. Leave the bottom a bit thick for insulation, give a bit of a grip for greasy finger passing, and don't use a surface finish that might be affected by the heat of the unpopped kernals.

I don't use the edge of a bowl gouge for anything but hogging, preferring to gain the firm support of the rest and the stability of a constant angle bevel provided by the forged pattern gouge. Only drawback is keeping the proper angle around the corner to the button on the bottom. Sometimes you have to go to a shear scrape angle of attack. I run this rest, which reaches in almost seven inches. Sometimes it's tough to find room underneath, because he's designed as a bi-directional rest, but otherwise no drawback. Where he might need some help, or where the opening might be so narrow only a bar rest will do, there's the extender.

As to hook or ring tools being used on face grain, they're well capable, but they work below centerline, and you lever the rest to keep control because of the strange angle. You can do the same with your swept-wing bowl gouge if you like.

The rest you show is what I need badly. Alot of the bowls I carve are deeper and it is a PITA to carve, not counting the lack of gouges I have.

I'll have to fab a few and have someone weld them. Is their a cheap place online to buy different rests?

 

[MichaelMouse]

The curved iron rest is from Craft Supplies, though you have to be careful not to get something like the "S" types, which are much shorter in reach. The offset for the rest, as is obvious from the color, is a Delta item, and I haven't seen it many places since purchasing mine. Woodworkers' Supply was the source for it.

Souce for good tool rests of the cylindrical stock type is http://www.bestwoodtools.com/ , though they're neither optimum, in my opinion, nor are they cheap, until you think of saving one piece on the final pass by having the deep support rather than hanging a gouge out there.

 

[TurningDog]

the cheap way to go about modular rests it buy your post and make the rest. I use sorby posts since I origianlly started with modular rests from sorby. I also like them because I knew going into it what the thread size was something no one would post about that in for other compainies, not to mention best wood tools refused to answer that question on 14 different email attempt. Well not quite true they answered the last one 4 months aftert I went with sorby and 6 months after I sent it saying it was proprietary information. I am sure it is a standard thread, and if I had gone out and bought it 10 minutes or less at the hardwarer store would have given me the answer I was looking for.

BTW I paid less than $10 delivered for my HSS bit and tap on ebay and it came to me straignt from sheffield england. Sorby is a standard m12 thread.