Wednesday, 31 August 2011

Hornbeam Bow

A new project has got me excited, a guy just starting out in archery asked if I did cheap Ash longbows. Well the answer is no, but I asked if he might be interested in a Hornbeam primitive as I have a stave nearly seasoned and if he was willing to take pot luck we might strike a mutually agreeable bargain.
The Hornbeam is a bit knotty, (It's the bit cut last December 31st) and very teasing, the guy is tall with a long draw.
Now the problem is, if I make the bow long then I have to incorporate a couple of huge knots on one limb, but if I make it shorter, it will be under a lot of strain at 30 odd inches draw.
The other tease is the arbitrary and bonkers classification of 'longbow' by some archery societies. I think I may be able to make it meet the GNAS definition of longbow, whilst also meeting the NFAS definition of primitive! Maybe it will be a primitive longbow.
Anyhow, I spent a bit of time de-barking and roughing it out on the bandsaw.
As I've not used Hornbeam before it should be a good learning experience.
The other problem is the stave has a big lateral bend, which if placed in the grip area I can probably straighten with heat.

My rough game plan is a bow of about 5'9 -6'2" long, the back following the underbark surface of the log and the belly gently rounded, or squarish with rounded edges.
If the thickness is no less than 5/8ths of the width at any point and I put a bit of horn on the nocks it could be called a longbow by the GNAS. If I feel it needs more width I'll just call it a primitive.
As I'm having to heat it to straighten it at the grip I might also heat treat the belly.
I'll aim for about 45#at 28" 50#@31".
The back will have some nice character, so it may be a character longbow? Who knows, anyhow I've called what I'm aiming for, time will tell if I succeed.

I haven't really worked the wood yet, but I've alread noticed it has a nice smell when sawn, sort of sweet and nutty, slightly reminscent of a roast chestnut.

Sunday, 28 August 2011

Stave anxiety

My stash of Yew which was cut last November hasn't yielded as many staves as I'd hoped and they are a bit knotty. One of the problems is the tree surgeon who cut the logs didn't cut them long enough (I'd asked for 7-8' but they were just over 6') some of the staves are barely long enough. The extra length would allow any big knots to be positioned at the centre of the bow or cut off one end.
One stave had a huge knot which once I'd chopped it away resulted in the stave being only enough for half a bow! Of course if one of the others isn't up to scratch I can always splice two halves together.
I've just got six and a half staves for longbows
On the plus side there is a half log which looks very nice, too short for a longbow but it will make a nice primitive or two billets to make a spliced longbow.
I've also managed to salvage some offcuts from the last longbow I made. These may just make a low draw weight takedown (carriage bow) which is something I've not tried before. The two halves are joined with a metal ferule at the handle.
Anyhow I've now stacked the staves up on their shelf for a few more months, hopefully next time I look at them they won't look quite so much disappointing as challenging.

Friday, 26 August 2011

Quiet week

We had a big family 'do' last weekend and I'm doing some plumbing DIY up in the loft, which is ok when it's raining outside as it's no too hot.
I've found some time to look at the first of last November's Yew.
I took a quartered log and chopped off the corners with my axe so that I can get it onto the shave horse more easilly. The heart wood felt nice and crisp, the sap wood felt a bit wet still, but I haven't de barked it yet. If I can work through the staves roughing them down a bit debarking them and having a good look to see how many bows I can get that will be time well spent. The staves can then have another 4 months before I really start work on them.
half past five now and I've been flooring a bit of the loft, but managed to debark and trim 4 staves in total. Some are a bit knotty, but they look ok.
I'll try to get 'em all done over the weekend.

Wednesday, 17 August 2011

Tweaking the bow set up.

Having shot the bow a fair bit, I could feel some areas of the grip hard against my fingers. Shaping the grip to fit the hand is a matter of relieving any edges or high spots which you can feel in use, a big old half round file does this nicely. I'm not taking off much wood as if making a pistol grip, it's just carefully removing the high spots until the bow sits nicely in a relaxed hand.

Shooting two batches of arrows I found the lighter 70grain points on a softer spined (more flexible) shaft flew straightest, but with a hint of hand shock and residual string vibration/noise. Going up to the 100grain point and the stiffer shafts, they flew a bit smoother but went slightly left (shooting at about 9 paces in my garage). I took some wood (about 3mm) off the arrow pass to allow the arrows fly without having to flex around the bow quite so much, the grouping seemed more in line with the lighter arrows after that.
A little adjustment of the string grooves at the tips of the bow ensured the string was tracking nice and centrally, one tip had been pulling the string a whisker to the right (away from the arrow pass).
All this shooting left a slight mark where the arrows were rubbing, this allowed me to adjust the nocking point up slightly so that it was correctly positioned just above that arrow pass mark. This means the arrow leaves the bow with the fletchings slightly higher than the point, this prevents the fletching ripping into my knuckle which had the point of the arrow resting on it at the moment of loose.
I usually wear a glove on my left hand but not always. A while back a fletching scratched deeply into the knuckle, I though little of it until a week or so later it was red and itchy, I probed it with a needle and a 1/4" sliver of quill popped out! It healed very quickly after that, just as well it didn't take root and grow giving me feathered hands.

I suppose it's a matter of style and taste, I've had very favourable comments about the tiller of the bow, but I feel the lower limb looks a trifle stiff, I will leave it until it's been thoroughly shot in over several weeks and maybe then make a slight adjustment. The lower limb, being shorter is under greater strain and thus may take more set over time, so I don't want to be hasty.

These minor adjustment allow you to get the best out of a bow, even if the effect is small or even merely psychological, it's nice to feel you have taken the trouble to get to know your bow. Those shooting modern target bows or compounds doubtless like to fiddle with their pressure buttons, cam timings, sights and other gizmos. A bow you've made yourself provides that same satisfaction in a more intimate and less expensive way.

Sunday, 14 August 2011

Osage Pics

I shot the bow at the club today, it needs some final tweaking and finishing but I'm pretty please 47# at 28" which gives me a couple of pounds to play with if necessary.

Thursday, 11 August 2011

Osage on the Tiller

It's at a low brace now (3-4") and I've got it on the tiller, it's been drawn back to 30 pounds in the pic. Tricky to work in the garage with a bear in there!
Up to this point I've been getting the limbs about even by measuring the thickness at 6" intervals to make sure they are roughly even and slowly tapering towards the tips. Now it's on the tiller I will do it more by eye and feel. Measurements are very handy but its dangerous to try and do it all by numbers, you need to be constantly looking at it and feeling it. Even a relatively even stave will have wiggles and twists which will be appreciated best by running the limb between finger and thumb. You can't always measure the limb easilly when it has curved surfaces. Even though this bow has almost rectangular cross section there is still a curve on the back and some twist which can make measurement tricky or deceptive.
I did add a thin sliver of Osage (Just about 1 growth ring thick) to the belly of the recurve where it was kinked, this may well get rasped off as the bow progresses, but I wanted to keep the recurved tips stiff and didn't want to risk pulling out the curve as I tillered it.
the tips have been left pretty wide too, this will give me room to adjust the alignment of the string so it runs nicely up the centre of the recurve whilst sitting right at the handle too.

Oh, and the bear? He's a 3D target which I brought back from the club to remove a length of steel bar which had got jammed in his mounting tubes. There are two steel tubes which run up into the foam which allow the target to be fixed firmly to the ground by hammering steel rods into the ground and then putting the target onto them. Somehow a rod had got pushed right up inside.

UPDATE:- I've been tillering it off and on all day, it's now up to a full brace and 45 pounds at 25".
I'm aiming for 45# @ 28" so there's a little way to go yet The recurved tips are still thick, but are becoming narrower and narrower as I'm adjusting how the string sits, the limbs are being narrowed and trued up too so that now it's hard to tell the chunky fat limb from the skinny one which had barely enough wood. As it's getting close, I'm also rounding off the square edges a fair bit and being more careful with the finish. I'm hoping to shoot it on Saturday at the club to give it a good try out. It's shot an arrow, just a quick plink from a short draw but it works, I've still got the adjustable tillering string on it. It feels very taut and lively, there is very little set and the recurves are remaining stiff as it's drawn (static recurve as opposed to working recurves)

Monday, 8 August 2011

Bending Finished

I lopped about an inch and a quarter off each limb tip and re-did the bends. This shows why it's best to start with a stave at least 2" longer than the desired length.
being shorter and having recurved tips it's a bit stiffer now so I've been thining the limbs some more.
It's flexing a bit and nearly back to brace height. Pulling on a long string on a reflexed bow can give a false idea of the poundage so I need to get it on a short string at brace height soon, but without overstressing it.

Saturday, 6 August 2011

Better Bending Technique

Here I've jigged the bow up to straighten some sideways bend and then a separate bend to recurve the tip.
The big difference is I've shrouded the limb in aluminium foil to direct the heat along the limb for a better spread and more even heat, I set the heat gun to 200C and gave it 20 minutes (pic1). I then clamped it for a few hours (pic 2).
For the recurve I also put a thin length of steel to hopefully spread the heat and the pressure to stop splintering.

Osage Bend Pics

You can see where the bend hasn't really followed the curve of the jig. I'd rasped it down before this pic was taken, that's why it looks a bit thinner at that point. The good new is that the splintering didn't seem to go down very far, so hopefully it will be fine.
In the middle pic you can see it jigged up to remove some of the twist, there was also a clamp just beyond the centre of the bow which was being tensioned by rubber straps to hold the bow with some torque on it while I got the other clamp and wedges in place, the straps remained until the bow had cooled down thoroughly.
The last pic shows the much improved limb alignment and flipped tip.

I shall try to be a bit more carefull and well planned when I do the other limb. It's easy to end up with a bow hot on the jig and be standing there holding it in tension with no clamps, wedges or strapping to hand, and not even a cup of tea within reach!

Friday, 5 August 2011

Heat Bending Osage

The bow has a few spare inches of length, so I thought I'd put a hint of recurve on the tips and try to take out some twist.
I'm not sure if I've screwed up...
Osage is a bit more brittle than the Yew. I clamped it on the bending jig, wiped some olive oil on it and applied the hot air gun set to 220C, I gently applied pressure and after about 15 minutes I felt it starting to bend, however the bend isn't very smooth and some splinters lifted on the belly of the bow. Hopefully this is only superficial and will come out as I work the belly down during tillering.
I've noticed that on the Primitive Archer website and in the Traditional Bowyers Bible they often add a thin steel strap over the belly of the bow where it is being bent, this helps distribute the force more evenly and helps stop splintering.
I've never needed this with Yew, perhaps my impatience didn't help and I should maybe have made sure I'd heated the wood more evenly, however I think it's a recognised problem with Osage, and it just means I've gained more experience.
Worst case I'll add a thin strip of extra wood at the bend on the belly of the bow and blend it in with a bit of a string groove near the tip. Pics later.

Monday, 1 August 2011

Osage Bow

The bow is coming along slowly, it's floor tillered (that's to say it flexes when you lean on the grip with one hand, with one end on the floor and the other end gripped in the other hand).
I've put it up on the tiller with a string which will just fit onto it, but it's still too strong.
Being rectangular in cross section it looks a bit like a bit of 2"x1"!
There is one nice ripple on the lower limb in the pic where there was a knot.
I'm taking it slow and steady, the wood cuts nicely but can tear and leave nasty hard sharp edges and splinters. Areas where there are knots or the grain is uneven are being worked with a rasp rather than the spokeshave to avoid that problem.