Spiral Grain - How much is too much?

[Crogacht]

Hi all,

I'm just starting out, and I have split a few logs, but have encountered a bit of spiral grain.

One log which I know is a write-off has 180 degrees of spiral over 2 metres  , so that one has been set aside for firewood.

I have another log which has a mild spiral in it. So my question is, how much spiral is too much? Do I need to be searching for very straight grained wood?

I know wavy grain/knots/pins etc can be worked around in most cases, but spiral grain seems like a big problem.

Any help would be great,

Thanks,

Ben

[aaron]

I think even a little spiral is too much, especially for a beginner. What species are you working with? I recently brought home what I thought was one of the best vine maple staves i ever saw only to discover it was the only VM i ever cut with spiral grain. Most species, you can tell by the bark, but not with VM

[Crogacht]

Thanks for the reply

Well, I'm actually in New Zealand, it's a beautiful place, but there are very few people making bows here.

I'm basically looking at the mechanical properties of a wood and trying to target certain species with a little advice from the few other bowyers I know and then going from there.

Most nz natives have mottled or patchy bark, so it's hard to tell what the grain is doing a lot of the time, but I have learnt to look at the shape of the trunk now. Many natives form buttresses and even on young trees the ridges and raised parts on the trunk give away the nature of the grain most of the time.

We have a little black locust where I live, but it's mostly inaccessible. Yew is very uncommon, osage is non-existant.

The species is native to New Zealand, and is called Black Beech. There's a link here which will give a bit of an idea of the properties of the wood.

http://www.nzffa.org.nz/specialty-timber-market/showcase/new-zealand-beech/black-beech/

As I said there's not too much info around where I live, especially in regards to native timber. The native people of New Zealand (Maori) had no use for bows, and never made any.

I've read the bowyer bible series quite a few times, so I've picked up a lot from that, and it talks about how to deal with most issues, but spiral grain doesn't seem well covered that I could find.

Any idea how you deal with it? Or is it best to just avoid?

It seems like if you took a log with a spiral grain and cut a stave as you normally would, you'd have fibre running off the edge of the bow and when you tiller it and draw it back I imagine the wood would probably have some twist it in then also.

[Pelo]

I've invested a lot of time in spiraled lilac (straight dense beautiful) staves only to have them blow apart dramatically in final tillering. I've tried making them as wide and narrow as possible. Not to say it can't be done.

[Crogacht]

Yeah, it seems like some of the stronger woods might tolerate a bit of spiral, but most woods won't. I might need to keep searching. I have some pretty nice elm to keep me busy for awhile anyway

[PEARL DRUMS]

Most woods will let you get away with 100 degrees or less. If you don't want to work twisted wood you will need to study the bark patterns closer. Pick a groove in the bark and follow it up. It should stay in front of you as you gaze upward, if it starts to curl around the tree the wood inside will do the same. Straight bark pattern = straight staves. Another trick. Keep the logs halved if you can. The moisture can still escape, but its harder for a half log to twist as it dries compared to a 2-4" wide split. Gradual drying is always better than intense drying.

[Crogacht]

Ok, that's good to know then. 100 Degrees over what length? 2 metres?

I try my best to study the bark, but I'm working with examples like this, hahaha:

http://www.conifers.org/po/pr/taxifolia5.jpg

I've kind of started to study the shape of the trunk, any bulges or ridges seem to follow the grain the same way the bark usually does.

I'm currently just drying my wood in the roof of the shed, it gets some decent airflow with the doors open, so it should be fairly gradual I hope. Some of our wood here shrinks a lot though due to high moisture content I guess.

I'd love some osage/yew/locust or something to work with, but I think it's smarter to use what you have in abundance where you live. It'll just take a bit more thinking and trial and error I guess.

Thanks for the advice

[PEARL DRUMS]

100 degress over 2 meters is fine. A wise man once told me that if the string stays on the bow, its not twisted too much!

[JW_Halverson]

I once took about 120 degrees of twist out of 6 ft of mulberry.  The ELB I made from it is still in use today. 

It took a week of Sundays and almost killed my heat gun taking out a little twist every 6 inches or so at a time!  I bet it was more luck thank skill, I just didn't know it wouldn't work!!!  I would love to tackle that 180 degree drill bit stave of yours to see if it was possible. 

Anything up to 90 degrees IF IT IS EVENLY DISTRIBUTED ACROSS THE 2 METERS of stave is do-able.  You are not taking all the twist out in a short length, after all.  You are taking out 8 or 10 degrees of twist at a time.  How do you eat an elephant?  One bite at a time.

Good luck, post pics!

[Crogacht]

Thanks Pearl Drums,

My black beech is probably 60 degrees over 2 metres, and it's a tough wood, so it might be perfectly fine.

Also have some good straight (ish) elm to work on until it's dry anyway

Thanks again

Ben

[Crogacht]

Awesome JW, thanks

I'll post a picture of both later on. Sounds like fun haha.

[Crogacht]

Photos as promised.

The twist in the black beech is probably about 50 degrees over 2 metres.

Next one show the Black Beech bark. This effect is actually caused by a mildew which grows on the honeydew excreted by the tree. Ants and other insects, native birds etc love it (the honeydew). Also highlights difficulty in identifying the nature of grain.

My kahikatea log, the split actually ran off the edge at about 1.7m, but it was on its way to 180 degrees of twist over 2 metres.

The bark of this one is also very tricky

The last two are of my kawaka stave, also called new zealand cedar by the white man. It's actually a pretty nice stave I think, but the wood is relatively weak, about half as strong as radiata pine I believe, but we shall see, it's worth a try.

Only about 15 degrees of twist in the kawaka fortunately and unfortunately.

[JW_Halverson]

The kahikatea has beautiful bark, natural camo!  But that twist is kinda scary, dude.

With a heat gun, I bet you could make the necessary corrections on the black beech, though.

[Crogacht]

Yeah that kahikatea twist is preeetty nasty.

I'll have to look into getting a heat gun. Also need to get a better workbench more suited for this kind of thing.

You'd have to rough it out a little first, right? What's the best way to lay the bow out for a piece of wood like that? Go straight down the middle then try and fix any twist, or try and lay it out a bit more diagonally?

I can tell there's some fun and games to be had in the near future haha

[JW_Halverson]

Lay out the bow according to the grain of the wood.  Shape the bow to the point that you would be ready to start floor tillering.  THEN you start heat treating and removing the twist. 

I would love to run over there and bring my heatgun along, if you would spring for a good bottle of Marlborough region sauv' blanc!