rough turning the largest bowl in a set with a coring system.

[Isaac Davis]

Does anyone rough turn the outside of the largest bowl in a set using a coring system rather than the traditional gouge and tool rest? Ronald Kanne has a video starring behemoth in which he does this, but I'm wondering if any of us mere humans with a oneway uses it for that. Been going over it in my head for a bit. Gonna try it this evening.

 

[JeffSmith]

Ronald has some great videos out there - havn't seen this one yet, but, the idea sounds like one that may be better in the abstract than in the real world. I rough the outside of a blank prepped for coring to take the best opportunity the wood affords at this point. get a good look at cracks, inclusions, etc and decide what I can live with. I core with the Macnaughton, so may be spoiled by the ability to shape as needed.

 

[Roger Wiegand]

I expect it can get exciting as you shear corners off the blank and such. It takes me much longer to set up and core than it does to just rough the outside of a log so it's never occurred to me to actually try it, especially since discovering the wood hogging capabilities of a 40/40 gouge. I will also frequently move and re-center the blank (doing the initial turning between centers) after the grain and other features begin to emerge, something that would be difficult with the coring setup.

 

[hockenbery]

but I'm wondering if any of us mere human

Like @Roger Wiegand said. Big danger of having pieces cut free and fly around.

A lot of folks don’t enjoy roughing because they make it too much work.
Many years ago Christian Burchard showed me what he called the A frame roughing cut.
It feels a little strange at first but it is so smooth and easy.

I cobbled this video together for the tips. You might consider try ing the A frame cut

A Frame Roughing Cut -

View: https://www.youtube.com/watch?v=qYuA5ywiRFo

 

[robo hippy]

McNaughton used to make 'left handed' coring blades for doing just this. There is also a video from New Holland Bowl Mills where they have a huge coring tool for doing the same thing. For me, it isn't worth the effort. Mostly because of how I use scrapers for the roughing work, which takes no time at all..... Part of this may be because I have a bandsaw that cuts 16 high, so I can get pretty much spot on parallel sides to my bowl blanks before I cut the slabs into circles. My chainsaw chop saw also made that same difference for prepping my blanks.

I am guessing that Christian's A frame is referring to his straight arms and foot stance to make the A frame....

robo hippy

 

[Isaac Davis]

Like @Roger Wiegand said. Big danger of having pieces cut free and fly around.

A lot of folks don’t enjoy roughing because they make it too much work.
Many years ago Christian Burchard showed me what he called the A frame roughing cut.
It feels a little strange at first but it is so smooth and easy.

I cobbled this video together for the tips. You might consider try ing the a frame cut

A Frame Roughing Cut -

View: https://www.youtube.com/watch?v=qYuA5ywiRFo

Interesting! thanks.

 

[hockenbery]

Interesting! thanks.

Everyone has to find what works best for them.
Maybe this works for you maybe not.
Try it on a couple of bowls.
You’ll either add it to your toolkit or forget it.

 

[Dean Center]

That's a nice video and clear explanation, Al. Roughing a round blank, even if position adjusted in the process, doesn't have to be to hard on the turner. Roughing an octagon straight from the chain saw, as I do, is inherently bumpy and hard on the turner. The A-frame technique, turning left handed, moving the tool rest often to keep it close to the wood and minimize overhang, paying attention to how open the flute is, and getting to a bevel rubbing/gliding cut on the side of the blank as soon as possible, can all make it easier on the turner. I'm curious how well the 40/40 works on an octagon, Roger, and will have to give it a try.

 

[DON FRANK]

I did try this once because I wanted to see if there was any real time savings. I used a blank that was cut on the sawmill so both sides were parallel and then cut it round on the bandsaw. This made it pretty balanced to start with. I attached it to a faceplate with shorter screws so they only dug in about 1/2". I cored it with the tailstock in place so it couldn't go flying when I was at the bottom. All went well. Then flipped it around and made a tennon for a chuck. Perhaps if you were doing several at the same time that were identical there would be some time savings because you could do one after the other without having to take off the oneway system. Then do all the tenons one after the other, then put the oneway back on and core them again.
This was a year or two ago when i tried it and I'm not really sure why I didn't do it again. I had the original oneway cutters then and I probably need to try it again with the new Hunter cutter I have as they are really good and certainly quicker.
I suppose you could do the opposite instead and core all the inside pieces first and then to the outside one last however that would involve changing out the coring bars and setting them up for the next core.

The machine that Ronald Kanne used was homemade and I think he called it the Mastadon. It Held the blank from the inside and cut the cores off the outside. It is a pretty ingenious design. It was certainly a time save because it was big and heavy enough that the blanks didn't have to be very true.

 

[Isaac Davis]

I did try this once because I wanted to see if there was any real time savings. I used a blank that was cut on the sawmill so both sides were parallel and then cut it round on the bandsaw. This made it pretty balanced to start with. I attached it to a faceplate with shorter screws so they only dug in about 1/2". I cored it with the tailstock in place so it couldn't go flying when I was at the bottom. All went well. Then flipped it around and made a tennon for a chuck. Perhaps if you were doing several at the same time that were identical there would be some time savings because you could do one after the other without having to take off the oneway system. Then do all the tenons one after the other, then put the oneway back on and core them again.
This was a year or two ago when i tried it and I'm not really sure why I didn't do it again. I had the original oneway cutters then and I probably need to try it again with the new Hunter cutter I have as they are really good and certainly quicker.
I suppose you could do the opposite instead and core all the inside pieces first and then to the outside one last however that would involve changing out the coring bars and setting them up for the next core.

The machine that Ronald Kanne used was homemade and I think he called it the Mastadon. It Held the blank from the inside and cut the cores off the outside. It is a pretty ingenious design. It was certainly a time save because it was big and heavy enough that the blanks didn't have to be very true.

Ah yes Mastodon, not behemoth. Cool, I never got around to trying it, glad you did.

 

[Neil S]

I rough the outside of a blank prepped for coring to take the best opportunity the wood affords at this point. get a good look at cracks, inclusions, etc and decide what I can live with. I core with the Macnaughton, so may be spoiled by the ability to shape as needed.

Ditto!
.