Ozbow

Excuse the BBQ cover in the pictures - it was the closest thing to hand and I wanted a backing that would contrast the timber colours.

When I made it over to Grant's Timber Mill in Narranderra I picked up a few boards with sapwood one side, heartwood the other. The board from which this bow is made was a slim piece of decking, which has limited the weight but it was a fun build and very quick to finish. It was also the lighter coloured Cypress, which is less than ideal, but it was had the heartwood/sapwood I was looking for and I invested little time or money in this. Truth be told, it took a little longer than an hour, but there was a lot of picking it up for 5 minutes & putting it down for weeks over a few months period. If you were to start it and not stop until it was sealed, you'd be looking at about an hour provided you had appropriate power tools and were confident in what you were doing.

Came in at 25#, which will drop to about 23#@28" once it's shot in, so I've marked it as that. 71" ntn - again, dictated by the board, 1" thick for the 4" long stiff-handle section, 2" fades (although the limb at it's thickest part is nearly the full thickness of the limb anyway, so the fades are fairly shallow - just enough to keep the handle stiff). Limbs are 1.5" wide at the fades, straight pyramid taper to 1/2" at the tips. My brother is going to add a leather arrow shelf & hand wrap to finish it off.
In retrospect, full draw, braced and unbraced pictures would've been useful. With such long working limbs and a short stiff section, the tiller is very circular - not perfect, but close enough to call without dropping below 20#. You do get a sense of the heartwood/sapwood split through these pictures, though. The grain was erratic, as would be expected with Cypress, but it is a low poundage bow and the sapwood appears to hold together extremely well anyway. As Perry said - this timber is resilient!

If you can find boards like this they're very quick & easy to make something that will propel an arrow. Perhaps not the best bow in the world, but an easy one! If anyone else has had an opportunity to use a bit of Cypress I'd be interested in any successes or failures. I've another, much thicker stave, that is currently being slowly worked into my first ELB...

Looks a sweet little bow!

Cool little experiment Nezwin, Aussie Timbers are quite remarkable in how resilient they can be. Keep us posted on how this Bow fairs.

regards Perry

Looks good mate

Very neat looking little bow there mate!

Might have to chase up some more cypress for some rather large experiments myself I think

Colin

The cypress is a really attractive wood up close. Do you reckon you could get a 40-50lber unbacked?

You know you Fella's have got me stirred up with this Cypress. A Property I Hunt down Mingoola way is lousy with the Stuff. There are big stands of Cypress growing in Shady Gully's along a Creek. I reckon I could find a Stave next Hunt over the Anzac Weekend.

Cypress makes good Hiking Staves and is a good Carving Timber also.
regards Perry

Theres a saw mill i pass on my way to Texas that only mills Cypress ,i'll have to pull up there next time i go and have a look

Thanks for all the kind words, everyone.

Hamish wrote:The cypress is a really attractive wood up close. Do you reckon you could get a 40-50lber unbacked?

Not sure, Hamish. The grain on this is wobbly with a fair bit of run-off, but it's fairly uniform through the length, if you get my meaning. Being a light target bow (perfect for some people I know) it's hard to make a call. It's complete conjecture based on limited experience, but the sapwood appears to be well 'bound', which I believe is common in a lot of woods. I know that Yew sapwood can take a certain amount of grain violation - perhaps it's because the live wood is more elastic or stuck together?

The ELB I'm whittling away (slowly) should be a respectable weight. It's come from a far thicker board that I've had to leave to season. It will be unbacked so we'll see how it goes!

Impressive result for an hour of work, well done. So if you make the next one around 3" wide at the fades it would come in around 45#? Would you trust it at 68NTN to up that poundage a little?

indie wrote:So if you make the next one around 3" wide at the fades it would come in around 45#? Would you trust it at 68NTN to up that poundage a little?

The board was only 3" or so wide so you would be taking pretty much your maximum width with that - you'd want to make sure it was a very choice board. A wider limb would raise the poundage but I'm not experienced enough to be able to say by quite how much. I can't really comment on what poundage I'd trust the timber up to, either. I'd certainly give it a try, nothing is fully known until it is tried! My first Cypress bow was in the 40#@28" range -

http://www.ozbow.net/phpBB3/viewtopic.php?f=34&t=15774

Also 68"ntn, so I imagine the Cypress (as a compression timber) can take those 40# - 50# kind of loads. Yew can take much more, and from the wood database numbers they're very similar woods. They even look similar, to a degree, and feel similar to be worked. Very different to the dense eucalyptus timber.

This one - http://www.ozbow.net/phpBB3/viewtopic.php?f=34&t=15852 - was only 35#@28" but across a far, far shorter working limb, which would seem to suggest the Cypress is very compression-resilient. Unfortunately it developed a twist which lead to a split forming in the static part of the limb. I can't say for sure what that says about the timber but I'm sure there's others out there who might have some thoughts.

The only other comment I would make about this timber is that you should try to pick out the darkest examples you can find. I believe this darker timber is denser & tougher than the lighter timber, which makes a difference in utilisation. The bow in this thread, however, was from the lighter timber though, it being that that was how the board was when I bought it.

Thanks for the response Nez.

Indie,

The following is part of a reply by Dennis LaVarenne to an earlier topic.

Dennis La Varenne wrote:
For any bow of given dimensions -
1. A bow which is made twice as wide where every other dimension is equal to the original will have twice the draw weight, but -
2. A bow which is made twice as thick where every other dimension is equal to the original will be 8 times the draw weight.

Dennis La Varenne wrote: Further to rule 2 in my post above about the cubed relationship of thickness to draw weight.

The following picture is an approximate illustration of how it works. There is a set of mathematical equations about it and the relationship is not as linear as this diagram supposes, but it is a useful working diagram using a 20lb bow as the exampled bow.

Diagram By Dennis La Varenne.jpg (29.82 KiB) Viewed 6911 times

So you can see that for every 14% of increased thickness or reduction, your bow's draw weight will either double or halve.

The principle being that you do not have to take much off or leave more on to get a significant change in draw weight. For instance, if your 20lb bow was 1/2 inch (0.500") thick at mid limb, then 14.28% of that is 0.714" which is close to 1.8mm to double this bow's draw weight from 20lbs to 40lbs or bring it back to 10lbs if removed..

Daryl.

I really like that bow.

I've picked through the 6' fence pickets at a couple of hardware stores, and found 3-4 relatively knot-free and straight-grained ones to play with. It's lovely stuff to work (and the smell is glorious!) and looks far more interesting/pretty than a lot of other timbers.

Cypress will always be damned hard to get flawless Timber, consider Splicing good Wood for a better Stave . PVA Glue is good enough for a permanent Bond. Epoxy fills the Gaps better with Rough and Crooked Cuts. Just stuff Hollows with Splinters of Wood. It is not hard, just take your time and you will end up with lots more Bow Wood

https://www.google.com.au/search?q=maki ... 4AQ#imgrc=_

I used to Splice the good halves of Failed Bows together. Picture if you well a Pyramid Limb and a Straight Limbed Bow, looks wierd, Shoots great. I had no drama's going down to 19mm and working Handle Bows. I just bound the Splice for added security. You can even take the Point off a Splice to form an Arrow Shelf.

regards Perry

perry wrote:Cypress will always be damned hard to get flawless Timber, consider Splicing good Wood for a better Stave .

Some sound advice there. I picked up a couple of 1.5" thick by 4" wide by 6' long boards where one half is usable, the other half has knots & heartwood one it. Cutting the board in half, first at the centre to have a 3' by 4" by 1.5" board, then again down the middle to get two 3' by 2" by 1.5" boards that can be spliced at the handle.

Ofcourse, Cypress is milled in huge quantities and if you've got the time & a friendly disposition, mill owners will usually let you trawl through the stacks to find those nearly-perfect examples that can be used without too much difficulty.

LB Rod 55 - did you get into your Qld mill? How does that stuff compare to what I'm posting?

One of the great benefits to making bows from cypress is the wonderful smell when carving it. And compared to the likes of Ironbark and Spotted gum, it is almost buttery under a bladed tool.

Good work on the bow Nezwin.

Going to try some of that CTP sometime soon?

yeoman wrote:......Going to try some of that CTP sometime soon?

Are you referring to....Phyllocladus aspleniifolius ?

Daryl.

I am indeed.

I brought a few select board back from Tassie with me and gave one to Nezwin.

Here on the mainland CTP is a rare, exotic timber. Down in Huonville where it's milled, it's sold almost as cheap as pine as decking.

Dave,

As supplies of vertical bamboo have been depleted I am looking at making my own vertical laminations out of celery top pine. Fortunately I have a supplier just 14 kms from home.

Vince Hamilton was using celery top pine in his longbows some 25 to 30 years ago. He used thin full width laminations between the vertical ones. Daryl.

Daryl, as a former student of structural engineering (only made it through to end of second year) I remember well the Area Moment of Inertia formula of b x d cubed/12. Little did I know that that and a few other structural bits of knowledge would be useful in the long distance future with trying to bend a few bits of wood. That graphic you supplied though is great and simplifies things a lot, thanks.

yeoman wrote:One of the great benefits to making bows from cypress is the wonderful smell when carving it. And compared to the likes of Ironbark and Spotted gum, it is almost buttery under a bladed tool.

Good work on the bow Nezwin.

Going to try some of that CTP sometime soon?

Thanks for the comments, Yeoman!

I finished a couple of CTP lam bows over Christmas - one for the missus, one for my neice. Neither came out at more than 20#@28", so I didn't post them in the forum but I did learn a lot about my new "movie bow" (your words!) form. Still getting a feel for it but the next one is going to be Cypress lams with a Hickory or Red Oak backing - hopefully in the 40lb range.

An idea is starting to form (excuse the pun) for a semi-horsebow, which I'll use the CTP for in the first instance, Osage once the design is ironed out. Think of a short, recurved bow with a short riser and static tips, only with tip wedges as opposed to heavy siyah's, reducing hand shock but keeping the early string tension that gives the noticeable 'flick' of a horsebow. I'll also include a more modern handle shape with arrow shelf, etc. Not dissimilar to my most recent design only shorter and with a more extreme recurve at the tips. I'm also keen to build an elm-backed, elm-bellied R/D bow some time in the future, using the lams you gave me on an adjustable form, with a bamboo core and a nice riser that will contrast the timbers.

I've also got a bamboo-backed Lemonwood bow to finish tillering, a bamboo-backed Spotted Gum ELB that is half done, a Lemonwood self/boardbow to untwist before tillering and a few others in various states of starting & finishing that are meant to be sent off to the UK when ready... There just never seems to be enough time! Or perhaps I'm just lazy or busy with the block! There's a never ending run of trees to plant, dams to clean, motorbikes to tune, gold to pan, sheep to dunk and topsoil to spread...

Have you had any luck with your Cypress or Lemonwood?

I'm a little bit ashamed t say I've done almost nothing with almost anything. The Lemonwood sits as beams, the CTP slightly less so.

However I did last week get a new bandsaw. The throat is big enough to fit the body of my old bandsaw through it without touching the blade, and the motor is three times bigger. So I'm pretty happy about that.

I'd be wary of using that elm as a backing. I tried a bit with a fairly catastrophic failure, due to a grain violation I could not at first see.

You sound very busy, and not just with the domestic stuff - the bows too.

yeoman wrote:However I did last week get a new bandsaw. The throat is big enough to fit the body of my old bandsaw through it without touching the blade, and the motor is three times bigger. So I'm pretty happy about that.

I'd be wary of using that elm as a backing. I tried a bit with a fairly catastrophic failure, due to a grain violation I could not at first see.

A new bandsaw should mean a ream of new bows posted to the forum, eh? Looking forward to them

I see your point with the Elm but I am keen to see if I can get something working with it, however light it may be. I was hoping that by pairing the Elm backing with an Elm belly they may compliment one another enough to survive with a bamboo core - particularly if the bow is only in the 35# or so range... If it blows up, I'll still have one of the three lams left which could be used as a belly, perhaps, although the crushing strength doesn't seem to be particularly high.

It does leave me wondering - the only 'strength' Elm appears to have as a bow wood is a low stiffness, which would reduce the rate at which it develops tension/compression loading. Apart from that, it seems to be fairly unsuited to bow making. Which begs the question, why does this timber receive praise from old timers? And why did the English & Welsh use this as a bow wood back in the pre-Warbow era?

Only one way to find out...

http://www.wood-database.com/lumber-ide ... glish-elm/
http://www.wood-database.com/lumber-ide ... s/red-elm/
http://www.wood-database.com/lumber-ide ... rican-elm/

I think the beauty of Elm is that for its density, it has above average tension strength. This does not necessarily mean it would make a good backing for, say, ironbark, but compared to Elm's strength in compression, its tension strength is very high. What this means is that the bow can be made with relatively high working strain and still shoot an arrow. It might take a lot of set, but a bow with a lot of set shoots an arrow much better than a bow that fails across the back.