Woodland Workshop

The weather wasn't too bad, but I set up a tarpaulin over my shave horse which kept the odd squalls of rain off me. I lashed my portable tiller tree to a big old Hornbeam and set to making a bow from a skinny piece of Hazel split from a log in January. I managed to get it finished and shooting by the end of the day, I only tested it to about 24" (~32#) as I didn't want to blow it on the tiller.

It's retained a little reflex which is pretty good, I'd had it seasoning strapped up with a few inches of reflex and being the skinnier half of the log it felt as if it had seasoned reasonably. The bow has it's back left completely intact with the bark left on, it's the first time I've managed this as previous bows have ended up being de-crowned.
Considering the weather we were quite busy and I'd set up shop near the entrance which drew a fair bit of interest.

I'd learnt from last year and only had one bow strung for people to look at, my big 75 pound Yew longbow. The reasoning being that not many people, and certainly no kids, could over draw it.

I'll tidy up the little Hazel bow at my leisure and hopefully tease it back to 26" or maybe even 28" I'll be going to a primitive archery meet next weekend, so I may take it along..

I've just had a contact on my website from a guy wanting to make his first Hazel bow, so I'll post more pictures and meaurements as I finish and fettle it.

The archery club had set up a 'hunting zone' have-a-go where people could shoot at 3D targets, there was also an archery 'clay pigeon' style shoot, aiming at foam discs with big blunt arrows from low poundage bows which was fun.

I didn't get to see round the rest of the festival as I was so busy, but everyone seemed to be in good spirits despite the odd downpour.

Footnote:-
I'd seriously discourage anyone from trying to make a bow in a day, I took this on half expecting to fail, and just doing it to demonstrate the process. If it went bang on the tiller, it would have just been a crowd pleaser.
By all means get it roughed out and onto a long string in a day, but save the real tillering until you are fresh.
Do it little and often with plenty of exercising of the bow as it is worked.
What I learned from the exercise is that it's just experience that teaches you that vital point at which to really slow down and how much wood to remove as it begins to bend.
Hazel is plentiful however and it's a relatively knot fee, clean working wood to to try out. Be warned though, a draw knife can stil tear out deep gouges when try to take off too much. I rapidly moved to my spokeshave set fairly fine which gave a nice surface on the belly.
So have a go, there's nothing to loose and plenty of experience to gain.

Back to the Ridge Back Bow

I've picked up the Yew stave with the weird ridge and it's begining to get back to brace heigh, it seems like good wood and relatively stiff considering the extra length I've left on it.
I made up a stringer in an attempt to get it braced. I got it to almost brace but could see it was trying to bend sideways. It's a bit panic making when a bow tries to do that, but with some careful adjustment of the cross section and the string line it can be tamed. The extra length is handy too as it allows some shortening and sideways adjustment of the nock positions. I've glued on some scraps of Yew to let me file temorary nocks in the back and to reduce one side of the bow at the tips to help bring it in line.

I'm hoping the weather will be kind tomorrow as it's the Beltane festival at the club and I'll be taking my shave horse and portable tiller tree to do some bow making demo's. I've even drilled another hole in the shave horse so the foot lever can be moved forward so kids can work it. Last years event was great fun, just hope we don't get washed out.

Comparing Two Longbows

I've got two bows finished, 55# and 60#.
Well is the 60# any faster? With some trepidation I shot it through the chronometer and averaged the 6 results getting a respectable 173.7 feet per second (fps) average.
I then strung the 55#, would it be just as fast? Again 6 shots and average, 168.9 fps.
I'm happy with those results and it's a bit of a relief to find the 60# is faster (I shot the same 3 arrows with each bow, 5/16" shaft 100gn point). I took a pic once I'd finished as I happened to get a nice group with the last 3 arrows from the 55#, you can see the reading on the chrono'.

I take the arrow speed divided by the draw weight as a sort of "efficiency" indicator. The 55# bow gives 3.1 whereas the 60# gives 2.9 implying the 60# bow is somehow less "efficient". I think the reason for this is light arrow favouring the lighter bow. If I repeated the test using my 11/32" arrows with the 100 grain points I expect the 55# bow would loose more speed than the 60 and the "efficiency" figures would even out or swing the other way. The arrows used for the test feel fine with the 55#, but the 60# definitely feels happier with the slightly heavier arrows.
Out of interest my best speed/draw weight figures tend to be the primitive style flat bows with 'Twister' my Yew primitive (45#) giving a figure of 3.7 Of course the longbow is designed for delivering energy rather than velocity as is better matched to a heavier arrow.
Figures need treating with caution of course and reducing the weight of the arrow will always give increased speed, but it's about matching the arrow to the bow rather than pure speed, unless you are into flight shooting where you are after maximum range with little interest in smoothness or longevity of the bow.
Explain more? Not sure what to explain really, I put "efficiency" in quotes as it's not really a measure of efficiency as it doesn't take into account the arrow weight, but it gives some sort of comparison.
These 2 posts explain more about velocity/energy/ speed and power.
http://bowyersdiary.blogspot.co.uk/2011/11/mass-velocity-and-energy.html
http://bowyersdiary.blogspot.co.uk/2011/10/graingram-scales.html
The chronometer has two photo cells which detect as the arrow passes over it. I've stuck thin pieces of cane in to show the active area which I have to shoot over. (The chronometer comes with metal rods which get severely bent when hit by an arrow so the thin cane is better!) I have two100w incandescent lights which hang down above it to give suitable illumination (fluorescent lamps flicker and can confuse it) Sometimes it's tricky to get reliable readings as the arrows can be flexing at short range as they leave the bow, I generally shoot at about 5 paces and take several reading to make sure I'm getting reproducible results. A chronometer is the only way to really tell how a bow is performing, as they can feel quite different and with the 2 bows I tested here it would be hard to tell which was shooting faster with out the chronometer.

Finishing Work + Video

This rain has given me 3 solid days working on the bow. Yesterday I got the horn nocks on and semi finished. I also did some general finishing work.
Today I've finished the nocks and continued the painstaking finishing work going over the bow with various grades of sandpaper often in diabolo fashion* working down to 400grade wet & dry paper. It's had a wipe of Danish oil and I've taken pics of some of the nice features.
The top left pic shows the lower limb with it's blush of pinkish purpley colour. The top right pic shows the hint of reflex on the tip and the heart sap boundary. Last pic shows the area of the grip with some real character, a blush and wriggle of grain and the only knot I filled just grazing the belly, to the right there is the slight depression in the side where there is a wiggle in the grain which follows where it was originally split from the log. It might be a shame to put a leather grip on it and cover the character, I shall see how it shoots. Being 60# the grip is fairly big and solid, I deliberately left a little extra sapwood on the back there too, so it feels good and doesn't have the sharp corners you often get between back and sides.
Here's a video of it being draw back to 28" and then briefly 29"

*Diabolo sanding/polishing is when you have a longish strip of sand paper, hold one end in each hand and work it back and forth. E.G with the bow horizontal, I have the paper draped over the bow and pull down on each side in turn, this is great for the round belly of a longbow and it also gives a bit of a radius to the edge where the back meets the sides.

Full Draw & Test Shots

I'm certainly glad I didn't rush at it yesterday. I reviewed the video I'd taken and could see the outer limbs weren't bending much, I got the right limb moving more and then worked on the left, it was still a bit strong on the left limb, and all this was at a low brace height.
I took some time taking out all the rasp marks with a scraper as it was beginning to get close to final draw length and weight. There were a couple of tiny pinch marks by the Devil's thumb print so I put some low viscosity superglue on it. I figured the area had withstood 60# draw weight and as the other limb was going to get eased off it would be ok. I went over the whole bow cleaning up the back and sliding my verniers over any suspect areas to check the taper was even and the bow was always slimmer towards the tip.

I also checked the string alignment by hanging it from the sting and looking along it, there was a hint of 'S' shape so I stuck some wedges of scrap Yew to the back at the nocks to allow filing of temporary nocks on the back which allowed me to narrow the tips from one side or the other to adjust the string line.

This has been an ongoing process through the whole business and is why I leave the tips about 20mm wide to start with. The string line shifts a bit as the bow begins to flex and finds it's curve.

Finally I shortened the string and got it to proper brace height, pulled it back to 60# and whew, it was 28" !
There was pretty much a days work getting this far, despite the temptation to rush to do it yesterday.
The 2 pictures are the taken from video of it being dynamically flexed, first at low brace height yesterday and the other is how it looks now.
I will doubtless have some fine tweaking to do, but I shouldn't loose draw weight as I can bring eack nock in by 1/4 of an inch to allow for any loss of weight. It is good to see the reflex still visible at full draw. There is a bit of an optical illusion as it looks to have increased from the left picture, that's just due to the sliver of sapwood glued to the back.
It still looks a bit uneven as the natural wiggles in the satve show up, that is one of the difficulties of tillering self bows
I borrowed the string from one of my other bows and tried a couple of test shots, it felt good.
No sign of problems around the thumb print. There is another area, a small natural depression where the grain dips just above the arrow pass which looks fine too. I'd been a bit worried early on as it might have been a weak point, but as the limbs were reduced it was apparent that there was probably plenty of wood there.
The finishing will be fun as some of these features will start to show up, there are a couple of nice streaks of purpleish red too.

Devil's Thumb Print

Ok, it's a fanciful title.

The stave I've just started on was cut close to a knot, and it turned out to be more extensive than I'd hoped, there are also some streaks of dark discolouration emanating from it which are of some concern.

Most of it has slowly disappeared, but it took several iterations of tweaking the centreline to minimise it. The pictures on the left show it when first roughed out, the pic on the right shows what's left of the 'thumb print' now, which is pretty much how it will remain.

Elsewhere on the stave there is some of the nice reddish purple colour which seemed sound enough on the 90# bow I built in January. I've made really rapid progress on the bow and it's currently to a low brace height and pulling back to 55# at about 20" (target is 60# at 28") .
There is still a long way to go as I need to carefully work over the back and I may reduce the length by and inch as it's for a guy who is 5'9" so I think 70 - 71" should look about right.
It's easier to make a longer bow as it's lower stressed, but I want it to look right, he wants it to shoot 180yards, which should be fine, but a shorter punchy bow with less inertia in the limbs may be faster.

The stave has a lovely hint of natural reflex at one end (that will be the top limb) and a hint of deflex on the other. Lopping off an extra inch will take out some of that deflex.

We are back to that thorny old question of the lower limb being tillered stiffer than the upper. Robert Hardy once told me one of my bows was upside down because the lower limb looked weak! I didn't actually argue but I showed him the natural deflex in the lower limb. If one is reflexed and one slightly deflexed which way up would you make it and why? Personally I'll stick to putting any deflex at the bottom, I've toyed with different ways of doing it and ended up thinking the tiller didn't look quite right at full draw.

Each to his own and if it ain't bust, don't fix it.

People often ask how long it takes to make a bow. I've put in two good days on this one and could probably have it shooting by tonight, but I won't do that as I'd be rushing and increasing the chances of it breaking. It would still need  the horn nocks, arrow plate and grip fitting and the careful finishing. The shooting in and final tweaking takes time too.

So it's one of those questions I try to avoid, but when pressed I generally reckon about 50 hours as I'm trying to get the best of the stave rather than just making a working bow as fast as possible. What is easy to forget is the time obtaining and splitting the wood out of the log and all the time I've spent musing over where to get the bow out of the stave.
There was a questionaire on a website that someone was doing as a school project, they asked:- How long does it take to mark out a bow? Well to mark out where you will saw a bow from a stave takes about 5 minutes, but the thinking can take a few months of consideration!

Busy Busy Bowyer

I got a couple of E-mails which sorted out my confusion, I think the previous post and a nudge from one of their club mates got the communication restored.
So I've started another bow, this will mean that the club in question will have four members shooting my bows by the time it's finished (fingers crossed).
I had one last big stave, it's quarter of a log with a couple of knots in the middle. I'd been looking at it off and on for a while thinking it might suit a very big warbow or maybe cut down the middle and make two bows, (you can see a pic of it in the post of Friday 23rd March, it's the large stave in the middle).
I decided to try and avoid the knots but to play safe and just lay out the best bow I could rather than being greedy and trying to get two. I've ended up with one handsome stave and another bit which may make a bow, but will certainly be good for a crossbow prod or some such.
The sap wood is pretty thick so I carefully ran it through the bandsaw to take off a continuous strip which may come in handy for backing a bow. The Oregon Yew I got has some bug holes in the sapwood so I may be able to use the sapwood strip to back that.
It's a bit nervy running it through the bandsaw as you can't afford a mistake which would cut right through the sapwood.
A bit of work with the drawknife has cleaned it up to a nice even layer and I can get on roughing it out further.
All this means I have two on the go at once which is unusual for me but I'm enjoying it, especially as these two staves are pretty knot free for a change!