Primitive Archer

Main Discussion Area => Bows => Topic started by: CaptainBeaky on April 07, 2013, 06:19:14 pm

Title: Hjarno-ish ash bow finished
Post by: CaptainBeaky on April 07, 2013, 06:19:14 pm
OK, it is now more or less finished, bar some decoration (which I am pondering) and a few coats of Danish Oil and beeswax.

Ash from a tree I took down last December, 68" n-t-n, 3" at fades, tapering to 3/8" at the nocks.

Nocks are ebony offcuts from the Box of Useful Items.

About 55lb at 30", shoots quite sweetly.

(http://www.pmjn.co.uk/Images/Hjarno_1/Hjarno_1.jpg)

(http://www.pmjn.co.uk/Images/Hjarno_1/Hjarno_2.jpg)

Can I convince anyone that the belly is a jpeg artifact?

(http://www.pmjn.co.uk/Images/Hjarno_1/Hjarno_3.jpg)

3" wide at fades

(http://www.pmjn.co.uk/Images/Hjarno_1/Hjarno_4.jpg)

Closeup of nock - now glued on and re-profiled.

(http://www.pmjn.co.uk/Images/Hjarno_1/Hjarno_6.jpg)

Non-primitive riser - sort of patterned after a Border Griffon.

(http://www.pmjn.co.uk/Images/Hjarno_1/Hjarno_7.jpg)

I'll update when I've finished the decoration.


Thanks for looking  :D
Title: Re: Hjarno-ish ash bow finished
Post by: CaptainBeaky on April 14, 2013, 06:18:28 pm
Measured draw weight again yesterday, now dropped to 48lb @ 30", after a little bit of shooting in my garden, and now showing about 3" of set.  :-[
More patience needed in tillering, methinks...

Decorated, oiled and waxed:

(http://www.pmjn.co.uk/Images/Hjarno_1/Hjarno_8.jpg)

(http://www.pmjn.co.uk/Images/Hjarno_1/Hjarno_9.jpg)

That's all, folks.
Title: Re: Hjarno-ish ash bow finished
Post by: lesken2011 on April 14, 2013, 06:56:14 pm
Nice job, Captain!
Title: Re: Hjarno-ish ash bow finished
Post by: H Rhodes on April 14, 2013, 07:39:55 pm
Cool bow. Love the finished art work. 
Title: Re: Hjarno-ish ash bow finished
Post by: dwardo on April 15, 2013, 07:03:35 am
Nice work  8) Where is it taking most of the set?
Title: Re: Hjarno-ish ash bow finished
Post by: Parnell on April 15, 2013, 10:24:42 am
Nice one!
Title: Re: Hjarno-ish ash bow finished
Post by: Hrothgar on April 15, 2013, 10:44:01 am
Good looking bow, tiller seems right on too.
Title: Re: Hjarno-ish ash bow finished
Post by: hatcha on April 15, 2013, 02:12:29 pm
That's a serious bow!  Nicely finished.  You mentioned Danish oil - what exactly is that?
Title: Re: Hjarno-ish ash bow finished
Post by: CaptainBeaky on April 16, 2013, 06:26:40 am
Thank you, kind Sirs  ;D

Nice work  8) Where is it taking most of the set?

Fairly evenly along the working part of the limbs, IIRC - I'll check when I get home.

...You mentioned Danish oil - what exactly is that?

Do you know, I have no real idea?  ??? Hang on....

[exercises Google-fu]

Tung oil, with synthetic resins dissolved in it, together with solvents to improve the application and driers to speed up the drying/curing process.

You wipe it onto the surface and rub it in/allow it to soak in then it sets into the surface, forming a tough, impervious coating in the outer layer of the wood.
I use it on the handles of almost all of the knives I make.

(technically, a varnish is resins dissolved in a carrier solvent, allowing application to a surface, where the solvent will evaporate, allowing the resins to polymerise forming a solid coating)
(if we are going to get pedantic, the solvent does not actually have to evaporate, as there are 100% solids varnishes, where the carrier solvent also polymerises, typically in UV-cured finishes - Danish Oil could therefore best be described as a high-solids room-temperature-curing varnish)

(this may be more information than required...   ::) )
(OK, I have to admit working in the surface coatings industry many summers ago, but I'm cured now  :P)
Title: Re: Hjarno-ish ash bow finished
Post by: gpw on April 16, 2013, 09:15:34 am
 Capn’ , just an idea .... a simple tensioned cable backing would help with the weight and set ...  A “primitive” solution ...
Title: Re: Hjarno-ish ash bow finished
Post by: hatcha on April 16, 2013, 06:00:19 pm
Thanks Cap.  And there's no such thing as "...more information than required..." ;)

Title: Re: Hjarno-ish ash bow finished
Post by: adb on April 16, 2013, 06:29:52 pm
With your pyramid design (3" at the fades) I'm surprised it took 3" of set. Was the wood still a bit green? Do you actually have a 30" draw? If not, why did you choose to tiller it to 30"?

If that bow had been mine, I would have gone for a more circular tiller with the pyramid design. Getting the tips a little lighter and coming around a bit more might have reduced the set a bit. Still a nice bow, however. Well done!
Title: Re: Hjarno-ish ash bow finished
Post by: CaptainBeaky on April 16, 2013, 08:27:16 pm
Thanks, adb - The stave started out with a lot of deflex, which I attempted to heat-bend out - I don't think I managed it. It may also have still be a bit green when I started tillering, although it had stopped losing weight and been stable for 4 days.
Yes, I draw 30" - those shafts in the bow further up the thread are 30" and I draw them to the head...

It started out as a normal pyramid design, but having seen the Hjarno artifact I fancied having a go at a leverbow, hence the outer 1/3rd of the limb is almost non-bending.
It does shoot nicely, so I'll play with it for a bit while I make the Mk2  ;D

My son has also now got his eye on this one - a bit of a jump from his 30lb@28" flatbow, but he manages to draw it all the way back to his normal anchor, so he may end up with it. (If I'm not careful  :o )
Title: Re: Hjarno-ish ash bow finished
Post by: rossfactor on April 16, 2013, 08:30:18 pm
Nice bow.  I like the limb profile.

Ash is a good bow wood, but I've noticed it can be pretty set prone.  Of course someone will come and tell us that design would solve that problem, but... I'm of a mind that some woods take set more easily than others.
Still I'm a fan of Ash.

Gabe
Title: Re: Hjarno-ish ash bow finished
Post by: mikekeswick on April 17, 2013, 02:51:18 am
Nice bow.  I like the limb profile.

Ash is a good bow wood, but I've noticed it can be pretty set prone.  Of course someone will come and tell us that design would solve that problem, but... I'm of a mind that some woods take set more easily than others.
Still I'm a fan of Ash.

Gabe

What you've got to ask yourself is WHY it took the set. Sure you can say that some woods are just set prone , well SOME maybe are but ash ISN'T one! The simple answer is that ash is extremely tension strong but not so great in compression when compared to it's tension strength.
A lot of people think that for less dense woods the simple answer to it taking set is 'make it wider'....well thats ok if it is the compression strength that is at fault. Ash however has this large difference between tension/compression strengths so the first thing to do it fix this problem. To make high performance ash bows you must must must trap the back heavily. If your limb is 2 inches wide the back should only be 1 inch. 1/2 off each back corner.
Just going wider actually makes the problem worse  ;)
Ash was the most easily available wood to me when I started to make bows. All of mine took plenty of set before I strated heavy trapping and heat treating. Bingo - less than 1 inch on them all. One of my very best flight bows is made of ash - it has less than 1/2 inch set and it's highly stressed. It shoots just shy of 300yds.
Title: Re: Hjarno-ish ash bow finished
Post by: dwardo on April 17, 2013, 06:30:25 am
I have played with our local ash quite a bit and found it all comes down to early to late ratio.
Some of the stuff I cut that was struggling under a big canopy had loads of real spongy airy early growth and little late which made sense I suppose.
When tillering it seemed to just keep taking set. When working down through the growth rings the early had the consistency of Cheshire cheese. Had two like this recently and gave up as soon as they started to chrystal, very early in tiller too.
The couple i made from the faster grown stuff with large late growth rings was far better.
I was watching a tv program recently about a guy who is trying to make a woodland business work as a coppice and they had a world class furniture maker in who was after ash timber. He dismissed the slow grown stuff with thin rings immediately and went for the opposite. The furniture maker did some very extreme steam bends in his work and knew what he was doing.
In regards to trapping pretty much all of the bows I have made from ash came from small diameter stuff so the shape was there already :) Heat never harms white woods ;)
Title: Re: Hjarno-ish ash bow finished
Post by: CaptainBeaky on April 17, 2013, 08:02:29 pm
Useful information here!  8)

Mike - I'm intrigued, to say the least, and also rather more than somewhat confused  ???

1. Trapping the back I followed, as you state that ash is weaker in compression than in tension, you then leave more of the wood where it is weaker. But:

2. Is it worth making anything wider than 2"?

3. If the limbs are a pyramid design, and I take 1/2" off each side of the back, when I get down to 1" width, there will be no back left at all...

4. What about using the same 3" down to 1" silhouette for the working limb, and trapping by a constant proportion of the width? e.g. taking 25% of the back width down, so 3/4" each side at the handle fades, reducing to 1/4" each side at the tip fades.  Worth a try?

5. I think I've been awake too long... I will  :-X until I'm a little more compos mentis tomorrow...
Title: Re: Hjarno-ish ash bow finished
Post by: CaptainBeaky on April 18, 2013, 05:58:27 am
Further thoughts this morning after some sleep...

This particular ash was in a small clearing on it's own, so wasn't struggling for light/water. Texture was good, not "Cheshire-Cheese'y" at all, and no crysalling even at the later stages.

I've noticed that this one has ended up thinner near the riser fades than at the tip fades, which would imply that I have made it too wide, or possibly tapering too much  ::)

I have the next stave from this batch partly reduced down to size - 681/2" ttt, this one has a slight reflex at both ends and a good straight section between.

Based on the above, I will try a similar design, but a bit wider at the outer fades, say 3" tapering to 11/2", trapped 25% of width on each side all the way the tip fades. Thick tips necked down to 1" narrowing to 3/8" at the nock.


Heat treated on the belly prior to tillering.

What do you think?

Title: Re: Hjarno-ish ash bow finished
Post by: hatcha on April 28, 2013, 02:30:45 pm
Interesting thoughts on ash - I think I shall definitely be trapping the stave I've got on the go in the shed.

Also - I got my hands on a can of Danish Oil and I LIKE it!!  :D