Help Cutting Blanks

[Isaac Litster]

In the summer of 2023, I got this mountain mahogany log. This is the main trunk, which is in two pieces. The first piece is cut at an angle, is 9-10" diameter, and 14" long at the shorter end, about 18" at the top end of the angled cut. The second piece is where the tree splits, and is also 9-10" diameter at the end, before splitting into two branches. I am posting this because I need advice on cutting it. The main features are large ring shake, and some significant checking (star and heart shake?). The second piece has ring shake and is a crotch.

The stakes are high, as this is very large for mountain mahogany. I cut it with my grandpa (probably shouldn't have cut it looking back), and spent hours bringing back pieces from the desert, driving them from Oregon to Tacoma, driving them onto a ferry in the back of a pickup truck, and ferrying them from Washington to Alaska.

I have a chainsaw and a Laguna 14bx bandsaw. Looking for turning and carving blocks. I've been cutting a lot of blanks with the bandsaw, but nothing that is complicated like this at this size.

How would you approach this? At least one cut before I can put it on the bandsaw, but where?

 

[David Wyke]

Ring shake is very dangerous to turn and I would advise against it. I see a couple of small bowl blanks maybe 2-3” thick if you cut the shake out. If it were me I would cut the end back enough to get the checking out and if you can cut straight with the chainsaw cut the section at the top of the log with no shake in it. If you use the bandsaw, which is what I would do, with a sled or good fence and have a good blade you could rip 2-3” boards off to make your bowl blanks or carving pieces. But make sure no ring shake is present.
Rip the log then turn the log so the flat is on the table of the bandsaw and rip another 2-3” boards off off, so the boards are from the outside diameter of the log with no ring shake.
I lost a couple of cherry logs due to ring shake, wouldn’t attempt to put it on the late as it will come apart. I wouldn’t even trust CA in the shake to hold it together.

 

[hughie]

Interesting this ring shake, its rare where I am. When I do find its not a major problem like you guys have. Shame though the wood looks like it would come up nicely.

 

[Brian Gustin]

For the crotch , generally a rip cut through both piths (rule of thumb) for best access to the flame figure but even then if you have cracking you're most likely SOL for bowl blanks-

For all of them , with the ring shake, very little for bowl blanks there (too dangerous) so I'd probably find the worst cracking that goes deepest (seat of the pants judgement) and split it there and then likely section it into spindle blanks along the worst cracks

If your intent is for bowl blanks, you might get lucky and end up with 1 or 2 usable decent sized bowls, but the rest of it I'd probably be looking at it as firewood, if not spindle blanks (boxes, etc out of the decent sized ones) But if your intent is for spindle blanks , the flame figure from crotch is likely best gotten when splitting the crotch through both piths, the rest , just follow the cracks. I learned my lesson about trying to turn anything with ring shake (unless you like to do risky stuff that needs way more patch/repair/hold-together work than turning work) so I would advise against trying to get bowl blanks out of them, you're likely to be disappointed, and then instead of a pile of usable spindle blanks, you have a lot of little chunks that, unless you plan to do miniatures, chess pieces, coasters, finials, etc, are pretty much just firewood.

 

[Dean Center]

First off, as you are well aware, this is a very uncommon wood for turning. You want to use it for something special, making use of its special features. For mountain mahogany, that's extremely, hard, dense wood with very fine grain. It's one of the few woods that can be hand chased for threads. It grows incredibly slowly (a 9" diameter might be 200 years old), endures conditions where nothing else that size can grow, and survives wildfires--it deserves our respect.

Second, it seems very surprising that it would get ring shake. Your pictures pretty clearly show ring shake, so this is curious. The shake might make a more common wood useless, but this is a very rare wood, and I would try to use all the pieces you can get. Maybe use small pieces in place of African blackwood for finials, for example. Or pens. Or handles for treen. Or miniatures of some sort.

Third, I would try thinking outside the box. Sure you can make a bowl out of it, but you can make a nice small bowl out of apple or something just as well. Go for special projects. Review the gallery here for ideas. Take your time figuring out what you want to use it for. Or who migt be special enough to receive the finished product. The mountain mahogany I have has been sitting in the upstairs of my garage, with wide swings in temp, for probably 10 years and it's been stable, even without ripping through the pith. I can't promise you won't get cracking, but this is one wood I personally would not rush to rip down the middle.

Finally, be sure to post pictures on here when you make something. It'll be a sight to see!

 

[John K Jordan]

Ring shake is a fatal defect, both for the turning and possibly for the turner. That said, there appears to be a lot of good wood outside the largest ring defect. Mountain mahogany is magnificent to turn, even in smaller pieces. I would slice it down the middle with the bandsaw, then cut the outer “safe” wood up in to smaller blanks for boxes and other small things. I’d give up now on making anything large such as bowls or hollow forms.

Even for the smaller blanks where the wood looks good, I’d examine them closely. I’ve had several trees, walnut and chinese chestnut that had both visible and invisible ring shake. To detect the invisible, prepare a blank on the bandsaw then cut off a thin slice of the end grain. Bend that, and if it breaks, mark the blank where the break is and cut off another slice and test it. If you eventually get to good wood, great.

The walnut tree with ring shake was so bad it ended up as firewood and pen blanks for someone (I don’t turn pens).

JKJ

 

[Darryl Fective]

Maybe if you cut it into smaller chunks, (and dried completely) you could fill all the checking and ring shank with resin. (need a pressure pot)

 

[Tim Hunter]

I wouldn't waste any more time on those pieces.

Tim

 

[Dave Landers]

I'll throw in one other thing I've found about ring shake -
Whatever happened that year to cause the ring shake - it happened to the whole tree. It's not just part of a growth ring - goes all the way around whether you can see it or not. And it will extend to other sections or logs from that tree.

This doesn't seem to be an issue for your logs, but I mention it in case others find this thread.

 

[Kent Reisdorph]

Interesting this ring shake, its rare where I am. When I do find its not a major problem like you guys have. Shame though the wood looks like it would come up nicely.

Here's a piece of tulip poplar with dramatic ring shake. Those little nubs are about all that's holding it toghether.

 

[robo hippy]

I would use the pieces inside the ring shake for finials. The stuff on the outside of the ring shake for small threaded boxes, or lidded boxes anyway. You won't be able to get a solid bowl out of that piece. Mountain Mahogany is a BEAUTIFUL wood. Oh, maybe some smaller jewelry pieces.

robo hippy

 

[Isaac Litster]

First off, as you are well aware, this is a very uncommon wood for turning. You want to use it for something special, making use of its special features. For mountain mahogany, that's extremely, hard, dense wood with very fine grain. It's one of the few woods that can be hand chased for threads. It grows incredibly slowly (a 9" diameter might be 200 years old), endures conditions where nothing else that size can grow, and survives wildfires--it deserves our respect.

Second, it seems very surprising that it would get ring shake. Your pictures pretty clearly show ring shake, so this is curious. The shake might make a more common wood useless, but this is a very rare wood, and I would try to use all the pieces you can get. Maybe use small pieces in place of African blackwood for finials, for example. Or pens. Or handles for treen. Or miniatures of some sort.

Third, I would try thinking outside the box. Sure you can make a bowl out of it, but you can make a nice small bowl out of apple or something just as well. Go for special projects. Review the gallery here for ideas. Take your time figuring out what you want to use it for. Or who migt be special enough to receive the finished product. The mountain mahogany I have has been sitting in the upstairs of my garage, with wide swings in temp, for probably 10 years and it's been stable, even without ripping through the pith. I can't promise you won't get cracking, but this is one wood I personally would not rush to rip down the middle.

Finally, be sure to post pictures on here when you make something. It'll be a sight to see!

I have quite a bit of interesting wood that I haven't seen threaded boxes of, that I want to thread. I've been looking for thread chasers. As soon as I get some, I will start learning to chase threads. As for respect, I have a lot of respect for woods like mountain mahogany and yellow cedar. I would feel bad making a poorly done turning with wood that was surviving fires since before America was founded, or a yellow cedar bowl from a tree that was growing during the Crusades. I would feel less bad for making something bad out of a maple tree that was growing in someone's backyard, planted in the 80s.

I am not interested in trying to turn a 4" bowl. If I get a blank that has some defects. I couldn't make a box or finial out of it, maybe I will turn a bowl with some "character". My dad was mad at me for cutting dozens of 1/4" and smaller squares out of apple, persian ironwood, and mountain mahogany. Still, for rare woods (apple is very hard to get in any clear size) I am going to use all of it possible.

I'm not rushing into turning it, however, it is still "green" so I would like to get it cut into pieces. With the ring shake, pith, and large cracks coming in from the outside, I don't want to let it continue to crack. I also don't have a lot of places to put a 50+ lb log. If it is cut and sealed, I can store it more easily and know what I have.

 

[Isaac Litster]

I would use the pieces inside the ring shake for finials. The stuff on the outside of the ring shake for small threaded boxes, or lidded boxes anyway. You won't be able to get a solid bowl out of that piece. Mountain Mahogany is a BEAUTIFUL wood. Oh, maybe some smaller jewelry pieces.

robo hippy

Had you mentioned that you got a load of mountain mahogany? Anything I need to know about processing it?

 

[Isaac Litster]

I'll throw in one other thing I've found about ring shake -
Whatever happened that year to cause the ring shake - it happened to the whole tree. It's not just part of a growth ring - goes all the way around whether you can see it or not. And it will extend to other sections or logs from that tree.

This doesn't seem to be an issue for your logs, but I mention it in case others find this thread.

This end has two large visible shakes, but from other smaller pieces I cut, there are other shakes, some that you can't see until it has been cut, and it starts delaminating instantly. I cut a smaller section the other day, and used a hammer after the first cut through the log to try to break out all of the ring shake, and invisible ring shake. This 9" log will get me a couple of 2x2s at best.

 

[Isaac Litster]

Ring shake is a fatal defect, both for the turning and possibly for the turner. That said, there appears to be a lot of good wood outside the largest ring defect. Mountain mahogany is magnificent to turn, even in smaller pieces. I would slice it down the middle with the bandsaw, then cut the outer “safe” wood up in to smaller blanks for boxes and other small things. I’d give up now on making anything large such as bowls or hollow forms.

Even for the smaller blanks where the wood looks good, I’d examine them closely. I’ve had several trees, walnut and chinese chestnut that had both visible and invisible ring shake. To detect the invisible, prepare a blank on the bandsaw then cut off a thin slice of the end grain. Bend that, and if it breaks, mark the blank where the break is and cut off another slice and test it. If you eventually get to good wood, great.

The walnut tree with ring shake was so bad it ended up as firewood and pen blanks for someone (I don’t turn pens).

JKJ

This definitely has invisible ring shake, I cut a smaller branch already, and after I mad the first cuts, I hit it with a hammer until most of the seperated wood broke out. I don't trust the bandsaw to make the first cuts, so I will likely do it with a chainsaw. The chainsaw has a wide kerf, so unfortunately there will be some waste.

 

[Bob Vaughan]

Years back I got some Chinese chestnut logs from a neighbor. I discovered a lot of shake late in the game. Dangerous stuff. I got very little yield from that effort.
Tim Hunter has a good point to consider. If the wood is nice enough, then maybe some very small pieces.

 

[robo hippy]

Mountain Mahogany is VERY HARD! Specific gravity is 1.1 or so, which means it will sink in water. Only fresh green wood I have had where I needed a dust mask. Mine came from N of Las Vegas, at 8500 feet. Sharp tools and small cuts. It, according to Allan Batty, is the only N American wood suitable for hand chasing threads. I have yet to venture into that....

robo hippy

 

[Kent Reisdorph]

Mountain Mahogany is VERY HARD! Specific gravity is 1.1 or so, which means it will sink in water. Only fresh green wood I have had where I needed a dust mask. Mine came from N of Las Vegas, at 8500 feet. Sharp tools and small cuts. It, according to Allan Batty, is the only N American wood suitable for hand chasing threads. I have yet to venture into that....

robo hippy

Wow, you're right about it being hard. 3200 Janka vs. 2600 for Osage Orange. I have heard hophornbeam is often used for thread chasing. I have some of those trees here, but haven't harvested any.