Ridgeback at Full Draw

I went over the belly with a file, scraper and 180 grit wet & dry paper getting it cleaned up. I sawed off 1/2" from each tip where the stringer grooves were (they will be reinstated on the horn nocks) and narrowed the tips. It's back to 60# at 28".

It turns out that 55# was the target, but that's fine as a somewhere between 55 and 60 is fine and will allow me a bit more tweaking.

Talking of abrasives and finishing, I find wet & dry is much longer lasting and less clogging than sand paper. I generally use 180 and finish with 400 grade. (I just went mad and bought some 120 and 240 as well, I had to have a lie down to get over the shock of opening my wallet).

The Bahco rasp I use is a medium rasp on one face and a file on the other (I think it's described as a cabinet rasp). The file side is great for taking out the rasp marks and with a draw filing technique it will give a good fine finish too. Draw filing is where you have a hand on each end of the file and push it along the wood like a drawknife or spoke shave. It gives a much finer finish as the teeth are all cutting at a very oblique angle and the gaps between then are no longer seen as file marks (google it if you want to see some vids of it). First time I came across it was when I was a nipper and I saw my Brother doing it, I thought he was mad until he explained.

It seems to have picked up a tad overnight and is more like 60# @ 27" but such are the vagaries of bows.
the left limb looks to have a slight kink about half way along, but that's more of a ripple in the heart sap boundary than a real bend. It's looking nicely rounded, I'm easing off the left limb a wee bit, but I'll get on to doing the horn nocks next, that will involve easing off the last 1/4 of each limb and rounding the profile.
I couldn't resist plinking an arrow out of it too.

The other shot shows my new tillering string, the last one was getting rather frayed as it was two old Dacron strings joined together by threading through the loops. I've made a nice new shiny Aluminium allow string shortener too. The string is 10 strands of Angel Majesty with nice big well served loops and a very long centre serving, hopefully it will do for tillering most bows, I can use an old longbow string which I made the wrong length for any short primitives.

Serious Progress with 'Ridgeback'

A few days of thoughtful tinkering has eased it back to a low brace with out too much sideways bend or twist, and I've had it back to 60# at about 22". I think we are aiming for 60# at 28" with some overdraw to 30" or so for longshots, warbow style shooting and clout etc.
It would have been good to take some pics of the sideways bend, but I didn't want to leave it on the tiller for long in that state. The main cure has been moving the nock on the upper limb sideways by about 1/4" and easing off the belly on the stiff side. If you picture the bow as square cross section with the back of the bow as the top (e.g Like it is on the tiller) I've been shaving away at the bottom corners as appropriate. At one stage I had a bend one way at mid limb and t'other way near the tip.
It's a bit of a catch22 situation as you don't want to bend it back too far while it's missbehaving, but bending it back at a decent brace height will help it come back straight.
As an example a reflexed stave braced to just an inch or so can easily try and flip up the other way on the tiller and whack your knuckles, but once it's pulled back about 10" it will sit happily.

I've been cleaning up the back before proceeding and I couldn't resist polishing up the ridge area to see how it will look. Rather striking, in fact it looks a bit as if the top limb has been hit by lightning.
It's now back to 60# at 24" and you can see how it flexes in the video, there's a nice bend over the middle portion but the outer limbs are stiff. Hopefully now it's coming back straight I can reduce the outer limbs without it all going sideways on me.
Update:- Blimey it's hard work, taken a good amount off the outer third of each limb and shortened the string to full brace, it's now 60# at 25" and the curve is looking better, but I've had to work to keep that upper limb from wandering.
Bit of a breather now, but I expect I'll have it back to full draw by tomorrow

Spine Tester & Matching Arrow to Bow

Before rushing in and reducing the arrow thickness I thought I should measure the spine (flexibility) of the arrow before I started. There are various slightly different definitions for spine measurement, but basically you support the shaft at it's two ends, hang a weight in the middle and measure how much it bends.

I've seen stuff saying the supports should be 28" 23" or 26" apart. I went for 26" as it is convenient for my arrow length. Two nails in my shelving and a small steel angle bracket (adjustable for different thickness arrow shafts) to act as a reference point does the job. A 2lb weight from the kitchen scales put in a plastic bag and hung onto the arrow with a piece of bent coat hanger and the job's a good 'un.

If you divide the distance between the supports (in inches) by the deflection (in inches) it gives a figure for the spine (or thereabouts). The reading with the unmodified arrow gave a spine of 31, I scraped along the central 20" of shaft with my scraper and then spun it up in the electric drill whilst rubbing sandpaper along it. The drill grips onto the point and the nock end was supported in a block of  wood with a hole in which was clamped in the vice.

I measured the spine again and it was down to 26.

The test shot, ok, it's just a single arrow but I had a good feel for the bow and I also know how to hit the spot at 10 paces. I took care to aim dead straight, no allowance for the kick... thwack the arrow thumped home about an inch left of centre.

A very obvious improvement, as yesterday I was having to aim way off right on every shot.

It's nice when the experiment does actually tie in with all the theory, normally my bows aren't to sensitive to spine, but the combination of low draw weight and very wide grip made the Hazel hypersensitive.

Measuring the arrow, it is 8.05mm diameter where I haven't reduced it and 7.45mm in the middle where it's been thinned. Not a vast amount, but enough to make a difference, the arrow is under a huge acceleration as it is loosed so I suppose it doesn't need much to have an effect.

It didn't take long to do two more arrows to be similar, (I didn't go mad looking for perfection). The results speak forthemslves, maybe a tad left still, but a vast improvement. I might take 'em down a bit more, but for now it's gardening weather.

Primitive Meet 2012

A great day out meeting up with on-line friends and old faces, some of whom I couldn't fit the name to! One exchange ran a bit like this.

Hey Bob, is your Dad here?

My Dad?

Yeah, that guy we shot with last year.

You mean Bob, he's not my Dad.

Are you sure? ( LOL)

There was a great atmosphere and plenty going on. I set up a couple of chairs, a rack for my bows and my tiller rig. I took a few of my unwanted rather twisted staves which I left for anyone who might want them

There were 3 primitive crossbows this time, two made by another Bob! We shot them at the big atl atl* target, so that people could have a go.
There was a group of young girls who had been trying the atl atls, who obviously wanted a go. I offered them a try and the youngest stood up. I hadn't realised how small she was, and I was worried she wouldn't manage it. I carefully explained how to shoot it safely and that with her cheek on the stock and the point of the bolt on the big black spot of the target she should hit it.

Click..thud.

Smack in the middle! Her sisters managed very well too, but she was a natural and kept coming back for more. I was impressed how well they did and how well behaved they were, no pestering or squabbling and they collected the bolts.  She dragged her Mum and Dad along to have a go too.
A young lad had also had ago and I saw him later throwing axes with great skill. One of the youngsters was also getting stuck in preparing rabbits for the pot. Great to see the kids enjoying themselves and joining in with enthusiasm.

One chap had a fine collection of native bows and arrows from around the world, it was great to see them close up and to be able to handle them, very inspiring, last year he'd been there with horn/sinew composites he was making.

There was a table covered in catapults (slingshots) Some were crafted from exotic woods, laminated and riveted. My favourite was like some Art Deco sculpture, you can tell I have exquisite taste, as that one wasn't for sale!

I set up my tiller rig and tinkered with the ridgeback Yew bow but mostly I was strolling about and chatting, all very informal and friendly. I shot round the practice course with Evan, the guy I've been E-mailing and 'Crossbow Bob' who was shooting one of his primitives made of Holly. I shot the new Hazel bow (very badly due to the kick left) Evan shot an Ash Mollegabet which he'd made. We managed to break and loose a few arrows. Later we shot some of the other bows I'd brought along and I had a go with the Mollegabet which thew an arrow with some authority.

I only attended for the one day, but I'm sure the proceedings and competition on the second day will be just as good.

My thanks to Wally the organiser and the people doing the yummy food. Beef burger with a fried egg on top, lemon drizzle cake and a cup of tea, bliss.

Not to mention the strange man try to make dead chickens dance ;)

After some musing about my Hazel bow I've decided to take some of my old arrows which have already lost a point once and waist the shafts to make 'em more flexible. I'll just scaper the shafts down over the centre third, of maybe grip the point in an electric drill and hold some sandpaper round them, I'll try and get them matched up to the bow. It's not something I've done before and it will be interesting to see if all my pontificating is correct and I can get them to fly straight from that bow. The other alternative is to build up the grip in thickness and narrow it to make it more centre shot, I feel that would detract from the whole point of the bow.
I'll report back.

*Atl atl, is like a huge long arrow thrown with a throwing stick.

Shooting the Hazel D Bow & the Archer's Paradox

I made a decent string for the bow, using just 6 strands of Angel Majesty. That's the thinnest string I've made as I wanted it as light as for maximum performance. I bulked up the nocks and centre serving with a few extra strands, but kept the serving down to a minimum. I've kept the brace height fairly low for maximum length of power stroke. Some find this rather counter-intuitive, thinking that a higher brace height and thus higher tension at brace will give give more power, yes it increases the early draw weight a little but reduces the length of actual draw (e.g 28"- 5.5" brace is 22.5" power stroke whereas  28"- 7" brace is 21" power stroke) .
To be honest I haven't done actual tests to prove this and I'm really just quoting from the Traditional Bowyer's Bible, but my experience tends to indicate that cranking up the brace height in an attempt to raise draw weight and power doesn't achieve what one might expect.
In fact scrabbling round trying to gain extra draw weight is fraught with problems, the two most effective ways are heat treating the belly or shortening the bow.
Shooting into the garage at about 10 paces I could see the white scrap of paper I was shooting at but couldn't see where the arrows were landing as it was rather dark in there and bright sunshine outside (yes it's finally stopped raining!) It shows the arrows are a bit stiff for the bow as it's only about 35-40# draw weight and is very wide at the grip. They are all kicking off left, due to the archer's paradox but the group is ok-ish considering I haven't shot it before. There is a little bit of wrist slap too (due to the low brace height).
Those are my lightest arrows (70grain points on a 5/16" shaft).
With bows everything is inter-related, so I may actually twist the string up a bit to raise the brace height, but I'd do it to hopefully reduce the wrist slap and it might also reduce the kick left as the arrow will leave the string a little sooner and won't be exerting so much bending force.

I'll be getting all my stuff together to go to the Primitive Archery meet tomorrow, and this little bow will get some serious shooting, so I'll spend a little time trying to tune it up a bit. (I'll post some pics when I get back).

Archers Paradox:-

The paradox is, why doesn't the arrow shoot off to the left when it can be seen that it points that way at brace height?

You can see at the start of the video the arrow is pointing to a place vertically above the knuckle of my left hand, but by the time I have let the string down to brace height it's pointing way off left. Assuming there is a target in the bushes, it's now pointing to a spot about a yard left.

So why doesn't the arrow go left?

Because it flexes around the bow, during the early part of the release it is going fairly fast and straight and the relatively heavy point has inertia which tries to keep it going straight. The back end of the arrow is also going fairly straight, but there is some flexibility in the string and some oscillation as the string slips off the fingers, this starts the arrow flexing and the laws of physics do the rest. So an arrow which is too stiff for the bow will kick a little left, one which is too flexible can be seen waggling in flight.

I get inordinately irritated by people who shoot compounds and modern target bows talking about archers paradox when their bows are 'centre shot', e.g The arrow points straight at the target at brace height.

The effect they are discussing are arrow tuning, and matching the arrow to bow and the method of release. As the string slips off your fingers it is deflected sideways and causes oscillations and flexing in the arrow/string and even the bow limb. That's not a paradox.

If you took the same two pics with a modern target bow with a cut away sight window, the arrow would be pointing the same way in both.

There are some good slo-mo videos on YouTube showing arrows flexing in flight. http://www.youtube.com/watch?v=WzWrcpzuAp8
I'm sure some people would wish to argue with the above, but Ha! That's the beauty of a blog I can indoctrinate you all into making primitive bows and put my view unimpeded. (exit stage left cackling wildly and rubbing hands in glee)

Full Draw Video 28"

I spent some time cleanining it up and fine tuning the tiller, eventually I plucked up courage and took it back to 282 draw.
It still has some reflex, pretty impressive for a sliver of Hazel.

Bow in a Day Details

It's made of Hazel 63.5" nock to nock.

47mm wide at widest, tapering to 13mm at the tips. narrowing to about 40mm at the grip (this will prob' get reduced further).

Lying flat on the floor the tips still show 2" of reflex, but I haven't taken it beyond 24" draw yet.

The thickness tapers from 19mm at the thickest point of the grip down to about 11mm at the thinnest.

You can see there's not much wood there !

Its the first time I've made a fully bend through the handle bow and as it hasn't taken any set yet I think it will probably come back to 26" maybe 28" which I'd really like so that I could shoot it in my usual style. I shall give it a good going over before I take it back further though.

I've spent an hour on it this evening and added horn overlays to the tips (just roughed out), this has allowed me to narrow them and adjust the string line, which you can see in the pic of it hanging up on a nail, you can see the natural waggle in the stave which I've utilised in the grip, you can see the string is biased towards the right (we are looking down the upper limb) to favour a right handed archer as the arrow pass will be on the right.

I shall try buffing up the bark and going over it with Danish oil to see if it will stay on. If it comes off I may add some abstract decoration of maybe a leaf and grass motif, it's fun to play with a quickie bow as I won't be scared stiff of messing it up.