Need advice on cutting blanks for hollow forms.

[Grey Darrah]

I'm new to hollow forms and I'm trying to figure out the best (most common?) way to cut my blanks for turning. I'm not a fan of small stuff (no offense to those that love little things), so I've got some maple and cherry logs that are about 15 to 20 inches in diameter and I want to maximize my hf's. For a bowl, most folks would take a 15" wide log and cut about a 15 or 16" long piece from it, then chainsaw that down the middle and turn 2 bowls from that.

What would be the most common way to cut that log piece up for an HF? One way would be to to just mount the whole log section and do an end grain piece (pith to pith). Would that be the most normal approach? It seems like splitting down the center like for a bowl is going to give me a much smaller form. Is there maybe an article someone might point me to that already talks about this?

Thanks for any suggestions,
Grey

 

[Richard Coers]

Well, if you want 15 to 20" diameter hollow forms, that's the way to go. Unusual to see forms over 6-7" diameter and 14" tall. Some native southwest forms are squat and larger diameter though.

 

[Stan Semeniuk]

Grey,
If you are just starting out learning hollowing I would really recommend trying a few smaller ones to get the feel. If you are going through a small opening and by feel alone it is a completely different animal to get comfortable with. I would also add going end grain can be a rough ride hollowing and you need to take in account that if your wood is wet on a large form and you are not able to finish it in a day wood movement and checking can be a problem when you return to hollowing the next day even if you wrap it in plastic.
Good luck!

 

[hockenbery]

There are two basic ways to hollow
Through the end grain
Through the face grain

Definitely start with 6” diamete 6” high forms.

When cutting blanks for end grain hollowing I avoid the pith and may avoid the sapwood.

The pith is rarely in the center of the log so a 20” log might make an 11-12” round blank for hollowing endgrain. Most hollow forms are hollowed through the endgrain

I do most of my Hollowing through the facegrain Most of John Jordan’s recent work is face grain hollowed. John has an excellent article in the AAW journal Spring 2009.
Here is a link to some slides I show in a HF demo Of hollowing through the face grain.
Slides show blank selection with a limb scar used for the opening to make and interesting rim.
http://swat.hockenbery.net/Hollowformdemo.pdf

These can use the the sapwood for accenting around the opening or use the natural edge as an opening. Most burls are hollowed through the farce grain to show the eyes.

 

[Bill Boehme]

Listen to the suggestions to work your way up to doing larger forms. It's very good advice. Doing very large diameter hollowforms requires a lot of experience and knowledge of wood movement.

 

[DON FRANK]

Also, decide if you plan to do "once turned" or twice turned HF's. If doing an end grain with the pith centered you will get less movement that alters the shape of the form but the orientation of the grain will look completely different for both styles. Ellesworth has a video made several years ago where he puts the log on the lathe pith to pith and turns it round. Then he turns the piece 90 degrees so the pith ends up centered in each side of the piece. He turns it to final thickness which reduces the chance of problems with the pith area cracking. Hollow forms are great fun but the advice of starting small and working your way up is sound.

 

[Grey Darrah]

Well, if you want 15 to 20" diameter hollow forms, that's the way to go. Unusual to see forms over 6-7" diameter and 14" tall. Some native southwest forms are squat and larger diameter though.

Sorry Richard, I was not clear enough in what I wrote. I'm not at all ready to take on 20" diameter hf's, but I've done a number of 3 to 6" forms to get the feel for hollowing with my tools. Now I want to work on the the size forms I like, which are exactly what you referenced (6-7" diameter and 14" tall). I'm just trying to figure out the best/most common way to cut a log to get that size blank.

Thanks,
Grey

 

[Grey Darrah]

Thanks so much...those drawings you added are exactly what I was looking for. I have already been hollowing a number of smaller pieces and am very comfortable with the feel of working through that smaller opening. Now I'm trying to figure out how to best cut the size pieces I want to get on my lathe. I'll try some face grain pieces for sure, but I was really looking for the best way to cut out taller, end grain blanks and you showed that perfectly. I do have some 30" diameter boxelder that I could still probably get a 14" tall face grain piece from.

Also, thanks for article link. I'm going to download that issue right now.

Thanks for all the help,
Grey

There are two basic ways to hollow
Through the end grain
Through the face grain

Definitely start with 6” diamete 6” high forms.

When cutting blanks for end grain hollowing I avoid the pith and may avoid the sapwood.

The pith is rarely in the center of the log so a 20” log might make an 11-12” round blank for hollowing endgrain. Most hollow forms are hollowed through the endgrain

I do most of my Hollowing through the facegrain Most of John Jordan’s recent work is face grain hollowed. John has an excellent article in the AAW journal Spring 2009.
Here is a link to some slides I show in a HF demo Of hollowing through the face grain.
Slides show blank selection with a limb scar used for the opening to make and interesting rim.
http://swat.hockenbery.net/Hollowformdemo.pdf

These can use the the sapwood for accenting around the opening or use the natural edge as an opening. Most burls are hollowed through the farce grain to show the eyes.

View attachment 25585

 

[Grey Darrah]

I appreciate and agree with your advice. I miss-wrote my original post...I'm not looking to jump into very large diameter hollow forms yet, just larger (more in height than diameter) than the 6 inch-ers I've been doing.

Thanks,
Grey

Listen to the suggestions to work your way up to doing larger forms. It's very good advice. Doing very large diameter hollowforms requires a lot of experience and knowledge of wood movement.

 

[Fadi Zeidan]

I’m newbie too, so take that with grain of salt. I’ve had great success with pith to pith turnings, but I had to drill the center out to the depth I need to achieve because it is very difficult to drill into end grain. I set the tip in the center hole and cut to the outside.

Side grain is much easier to hollow even with center not drilled out. I hollow it similar to bowls. If you do it side grain, align the rings so that it moves uniformly.

 

[DON FRANK]

Al, Your swat.hockenberry attachment is great. I missed that earlier. Those pictures helped me to visualize how someone can use a limb scar or sap wood to an advantage. Thanks!

 

[hockenbery]

Al, Your swat.hockenberry attachment is great. I missed that earlier. Those pictures helped me to visualize how someone can use a limb scar or sap wood to an advantage. Thanks!

Thanks for the kind words.
It is something I discovered a long time ago. I did a lot of wood collecting with bowl turners who would always give me the useless limb scars.

The limb will angle down toward the roots usually at something like 30 degrees.
Sometimes the limb will end in the part I hollow out. Also the limb scar will often have a hollow area.
But is reall doesn’t matter since it all works with the organic nature of the natural edge.

Have fun

 

[Dennis Weiner]

Grey
You may want to pick a copy of Turned-bowl Design by Richard Raffan for your library. There is quite a bit of blank preparation and form orientation illustrations. It was my bible when I was starting out.

 

[John Jordan]

http://www.johnjordanwoodturning.co...Orientate_Wood_for_Maximum_Visual_Impact.html
That will help. There are a couple of other articles there as well. Orientation is the key to hollow turning.

John

 

[Grey Darrah]

What a great article! Thanks so much for the link.

Thanks,
Grey

http://www.johnjordanwoodturning.co...Orientate_Wood_for_Maximum_Visual_Impact.html
That will help. There are a couple of other articles there as well. Orientation is the key to hollow turning.

John

 

[hockenbery]

Check Dale Larsen’s article - page 28 current AAW journal

It is about cutting bowl blanks.
you can use the same process for HFs - draw them on the saw face to visualize what the form will look like.
A sketch gives good idea of the Grain balance and where sapwood will show.

Somewhere between 5 and 50 blanks you begin to visualize the form without drawing it.
I carry a crayon for marking logs with my chainsaw.

 

[Mike Johnson]

Many turners try to force the wood into the form they envision, it is far easier to select the wood blank and examine the available wood grain and work with what nature has provided. Locating interesting wood grain from the various parts of the tree will offer up unique finished pieces, these are the parts of the tree that most wood milling operations ignore. The crotch wood where limbs grow from the trunk of the tree offer different grain orientation that the wood turner can select the different angles to mount to the lathe to provide unique grain to the turned piece. Locating a tree trunk that has multiple branches growing out in different directions can make for a spectacular piece if you can complete the turning process. The different grain orientation can be a challenge for the novice wood turner that is used to turning straight grain wood blanks. Harvesting these wood blanks with a chain saw takes time and requires a sharp chain saw blade to work your way through the various wood grain. You can also contact someone in your area that has a portable sawmill, they can cut these types of wood blanks for you if you give them a list of what you are looking for. You can also visit their wood processing area and find wood pieces or logs that may be what you are looking for. These specialized companies can provide special order pieces when they have a customer that has a request, you just need to give them time to select the right logs for the type of wood billet requested.

 

[Grey Darrah]

I just finished that article...very informative. But I still have to say that your initial drawing was perfect.

Thanks,
Grey

Check Dale Larsen’s article - page 28 current AAW journal

It is about cutting bowl blanks.
you can use the same process for HFs - draw them on the saw face to visualize what the form will look like.
A sketch gives good idea of the Grain balance and where sapwood will show.

Somewhere between 5 and 50 blanks you begin to visualize the form without drawing it.
I carry a crayon for marking logs with my chainsaw.