Saturday, 31 March 2012
Viewing it actually flexing rather than static seemed to show a lot of movement at one point about 5" along from the grip on the upper limb followed by a slightly stiff section. It didn't look so obvious in the bit of video where it was winched back more slowly.
Maybe I should get a long rope on the tiller so I can stand back and flex it, mind it's hard to get far enough back across the width of the garage. That's why the video function on the camera comes in handy.
I marked the place with some masking tape and checked with calipers, I could see it was slightly too thick either side of that point, especially where it approached the grip.
One advantage of making a longbow tillered full compass rather than in the Victorian style with a built up stiff handle section is there is no intentional 'fade' from grip to limb which is a potential problem area. The grip does end up being a little thicker but only because the thickest point of each limb meets there.
I eased off the belly with a little judicious rasping to even out the taper (also eased off the tip of the lower limb) and put it back on the tiller. It had gained about another inch of draw and looked much smoother.
I winched it back to 55# and it was nearly at 28" inches now, so I took it the rest of the way.
58# at 28" which is great as it leaves me some leeway to narrow the tips and clean the bow up some more without coming in under weight.
I've shot a dozen arrow through it now, it feels great, very smooth and it groups well.
Here's a video of it being flexed by pulling on the rope, it's nearly there and may look fine at first glance but you can see most of the bend is in the central third of the bow and the centre section of each limb isn't doing much flexing. Stiff tips are ok, but the centre of each limb needs to work just a tad more and that will take some off the load from the centre section. It will also get rid of the extra 3 pounds of draw weight.
On one of the the websites a guy was worried that he'd spent 3 hours tillering a bow and it was all over the place and ended up breaking. I offered some advice, most of which was slow down and don't try to do it all at once.
What looks great today, doesn't necessarily look quite so good in the cold light of morning. I don't often do more than say half an hour and take a breather. I'm still tinkering with the tiller on this bow, but it's using a scraper mostly now.
BTW. The start position of the bow is skewed, because it is supported where my hand grips it in use and is being pulled from where my fingers will draw it, this gives a more accurate view of the tiller than mounting it up all square. Some people clamp the bow onto the tiller, which in my view is a mistake.
Blimey this tillering has been driving me mad, I've been taking endless videos and even got my wife to video me actually shooting it. It's this 'the lower limb should be a bit stiffer' idea which I'm slightly ambivalent about. Anyhow to me it looked as if the top limb (right) was doing all the flexing and the outer half of the left limb was too stiff. So I've been fiddling about with a rasp and scraper on and off all day driving my wife mad talking about it.
Here's the final pic (grabbed from video)before I put horn nocks on it.
Friday, 30 March 2012
I suddenly found I had some help inspecting the work!
I've since had the bow back to 55# at about 25" from a full brace. Holding it up braced and peering along it showed it looked a tad S shaped, but checking out against a straight edge and peering down it as I let it swing fron the centre of the string revealed just a few points where the sides bulged a bit, these were generally where I'd left a bit extra round knots. A little work with the spokeshave set fine and a rasp/file and it's looking fine. There is the merest hint of curve which just offsets the string a whisker towards the arrow pass, which is fine for a right hander.
There was some discussion on one of the forums about 'Can a longbow be right or left handed'. The sort answer is 'Yes', but not by a very significant amount.
A bow isn't very sensitive to material removed from it's width, especially near the grip, which is nice and thick. That's why you can cut out a 3-4 mm hole and inlay an arrow plate without it exploding.
If you took a perfectly symetrical bow and then rasped off 3mm from the arrow pass, it wouldn't really effect the bow, but the stringline would now appear offset by 3mm towards the arrow pass and the bow would appear to be 'right handed'. If course it could still shoot left handed exactly as it did before you touched it, as there has been no change to that side of the bow. However, it might shoot slightly smoother right handed and be less sensitive to arrow spine (stiffness)
Well that's cleared that up!
I've shot a couple of arrows through the bow from a short draw just to try it. They went straight and true, if a tad slow, but it was from a very cautious short draw.
Wednesday, 28 March 2012
Note 50# on a slack string is substantially less than 50# on a braced bow (it probably equates to about 40... I did the experiment once but can't remember the exact figures... it's on the blog somewhere!).
It looked pretty reasonable and I gave it some flexing back and forth by pulling down on the string by hand whilst watching how it was bending.
Time to clean it up a bit and make sure the back is good and clean before proceeding.
As I inspected it I found a pin knot had popped out from the belly! This goes to show that my caution on the previous bow (from the same log) was fully justified. I inspected all the other knots and found 3 more which needed some excavation.
The first pic shows the popped pin, above it you can see another knot, which is shown from the other side in the next pic. Note, the W for 'Weak' pencilled on the limb (in both pics), this is how I mark any thin or weak spots so that I don't remove any more from there. The centreline marked on the back is also visible.
The second knot has been drilled right through with a 3mm drill, it drilled out some rather blackish stuff before getting down to sound wood, I also managed to snap the drill whilst trying to get it to go at the right angle to out in the right spot (it pulled out ok with a pair of pliers, as I hadn't been forcing it too hard).
You can also see how the sapwood is in a bit of a rough state, which is why I want to clean it up before I bend the bow too much.
So here are some pics of how I do the temporary nocks in the Yew longbow I'm currently working on, it shows the general idea applicable to any bow.
I file out the grooves with a 'Permagrit' needle file, a small saw and needle file will do it, but the permagrit one takes the wood off quickly and doesn't clog. I don't groove the back of the bow at all, it's supposed to weaken the sapwood and potentially start splits, but I don't really think that would happen as there is very little leverage at that point. Same applies with horn nocks and tip overlays, I don't think it's really necessary on bows under about 70#. Obviously it depends on the wood and the bow style, so it's better safe than sorry. A thin wide flat tip would be more likely to split than a longbow style more round section tip. If a split did start on a flat limb, a binding of linnen thread with epoxy massaged into it would stabilise it, or for a more primitive look sinew and hide glue. I might add some more pics but Google Blogger is playing up this morning.
Sunday, 25 March 2012
Looks ok from the back but the side view isn't the most beautiful. Maybe as the bow is worked down narrower and more rounded some of it will disappear and it will look better.
Hopefully it's stronger than it was before the patch.
Saturday, 24 March 2012
If you look closely at the knot in the last post you can see that half is sound and half discoloured, there is also some discolouration in the heartwood.
The first 3 pics show the view around the end of the stave by the knot, it looks fine one side and awful the other.
(A pencil line around the stave gives a reference point).
I decided to do a similar patch to the one I did on the last bow. I've taken more pics to show the approach of cleaning out the rot, filling and then patching.
Great care is taken to get both surfaces prepared clean and flat, although there is a slight concave curve along the limb where is cut away (but it's flat in the other plane). It's only one edge of the limb which has been rasped away. The view of the side and back show how the corner edge of the back and side has been taken off.
Epoxy has been applied and the patch held in position with masking tape and then tightly bound with about 4 layers of rubber strapping. We'll see how it looks when it's cleaned up tomorrow.
Friday, 23 March 2012
These are my last 3 Yew staves for this year. The longest and best has a fair bit of deflex.
The one on the left has great clusters of pin knots breaking through as a hugely undulating back, it also has a gaping knot in the belly about 4" from one end. It is too iffy for anything other than an experimental character longbow, although it could end up looking stunning. I'll possibly make that as a show piece.
The skinniest one is the one I've now picked up, it's a sister to stave that made the last bow (e.g From the same log, so the grew side by side.) You can see the knot a few inches from one end like the last bow and some of the knots on the edges of the belly which will hoprefull disappear as it's worked down.
I've got a 55# and a 60# to build, that's not a lot of difference, so I'll see how this next one shapes up.
The problem with the knotty stuff is that you can't just go at it with the drawknife as it will dig into the knots and dip down into the undulating grain splitting into the wood or ripping out great gouts. Some carefull roughing out on the bandsaw and tentative drawknife work can get you so far, but after that it's laborious work with a rasp until you have clean wood. Even the one has to be carefull as a spokeshave set for a fine cut can still dig in where the grain is dodgy.
Thursday, 22 March 2012
After shooting the longbow I noticed that many of my arrows were a bit short. I usually allow the point to be snapped off once and re-glued (snapped tips is an occupational hazard of field archery).
My wife's birthday is coming up soon and I thought I'd commission some handmade decorative glass from the wife of a colleague who makes some really nice stuff http://www.mjglassdesign.co.uk/
we went over to look at her work and she also showed us her dolls house which is crammed full of interesting stuff.
Now the poor little Victorian gent in the doll's house didn't have a longbow! That's just not right so I made one for him this morning, it turned out rather nicely and will be a nice little touch tucked into the corner of his study.
It's made of a sliver of Oregon Yew with proper heartwood and sapwood on the belly and back and horn overlays on the nocks.
Explain More! The magic box has been ticked, but I'm not sure what to explain. Maybe if a brief 'comment' was added stating the area of interest I would oblige.
Saturday, 17 March 2012
Friday, 16 March 2012
A matching horn arrow plated has been inlayed and I'd doing the leather grip, building up the back with a bit of hard leather first as there is a naturally concave area at the grip which feels harsh in the hand.
the first pic shows the built up leather after it's been carefully blended in. I taped a couple of pieces of a tin can around the bow either side to avoid damaging the sapwood as I shaved and rasped the leather. I rubbed UHU glue into the surface to harden it it and make it easier to shape, a craft knife, spokeshave and rasp were all used.
Second pic shows the bow resting on the vice jaws as the Danish oil dries. It's looking very handsome now.
Monday, 12 March 2012
Normally I'd tiller to a specific weight, but with this bow I'm very much working to the wood teasing my way around the knots and adjusting the tiller much later than I normally would as I need to keep the tips stiff, but without over stressing the centre section.
It's now back to about 62# at 27".
I'd taken it back to 60# at about 26" previously and the outer 1/3 of each limb looked a bit stiff, this shot is after I'd taken a bit off the belly of the last third of the right limb (except the last 4" where the not and patch is). I spent a fair bit of time checking the taper was even and fussing over the back of the bow.
Whew, I've just eased off the right limb a whisker and taken it back to about 28 1/2" !
it looked like about 64# but I didn't want to hang about studying it.
Due to superb planning, or maybe it was luck, I was able to use the string of one of my other bows and try some test shots. Most satisfactory, the grip will need a little shaping or a leather grip (built up with hard leather on the back) as the back of the bow is rather square. With my medium weight arrows (100gn on 5/16 shafts), it shot fast and true but with a hint of hand shock (possibly due to the grip being uncomfortable) I then tried my heaviest arrows 100gn piles on 11/32 shafts. Lovely and smooth, I shot about 20 through it and didn't feel in the slightest worried.
A carefull inspection of the bow showed no signs of any trouble (lifting grain, chrysals or pinches on the filled knots etc).
The tips can be reduced a fair bit to put on the horn nocks and I could maybe take 1/2" off each tip just to squeeze the draw weight back up to 65#.
Over all I'm very pleased, it's taken a hint of set, which is fine. I'll finish it off over the week and give it a good shooting in and a work out at the weekend.
Sunday, 11 March 2012
As I sat and worked I could hear Wuuuurrrpp Wuuuurrrp of the frogs in the pond, I couldn't help smiling, it was a bit chilly to start with but the sun came out and it was a glorious day.
I wanted to make sure the back was as flawless as is practical. I'm pretty scared that the damn thing will explode on me like the last one, I've even filled some tiny pin knots which I'd probably not bother about normally. I must have filled 8 or 9 in total by now, although one has almost disappeared off the edge of the bow and a couple of dodgy swoops in the grain have now turned into graceful curves.
I've got it to a low brace (about 4") and pulled it back to about 55# at 24".
I'm still not sure if it will become the 55# bow or the 65-70#although I suspect it may be the 55#. Whichever way it goes I shall take it back to 29" as a test of overdraw and shoot it in for a week before declaring it sound.
The belly is nicely rounded now and I've narrowed the tips a little, it' still a bit stiff in the outer limbs. Overall the curve is looking good and it's beginning to look really sweet.
The main problem is my state of mind! What I might do is set the camera up taking video when I take it back any further so if it does go bang, I'll at least have something to show for it this time.
Next step is to get it to full brace and exercise it a fair bit and carefully examine the back, for any lifting grain.
The thought of working some smooth white knot free Hazel later in the year is beginning to become very appealing!
Saturday, 10 March 2012
I compared the thickness of the two limbs at the six inch intervals and thinned the left limb to match the right one better. I got it on the tiller again and flexed it a bit and winched it back again, it was a bit better so I ran a string down the centre line and marked the taper of the bow again correcting some minor wobbles and narrowing it at the grip a bit from just over 30mm to about 28mm, I narrowed the tips a whisker, but not too much as I want to allow room for any adjsutment of string line.
Back up on the tiller, with a taut string (not properly braced, but no longer actually loose), I winched it back to 45#, took a pic, breathed a sigh of relief and took a break.
Having blown the last bow, I'm a bit nervous and there are still some tiny pin knots which need some filling as they are crumbly.
The last pic shows the nice ripple of knots up the upper limb and the slight natural deflex which give it some character.
If you zoom in on the second tiller pic you can just see I've drawn a smooth curved pencil line along the right limb, this is to help me to see the overall curve of the limb rather than getting distracted by the ripples.
I've been rounding the belly which will generate a bit more movement in the limbs with a view to getting it to somewhere near brace height. I was inspecting all the knots as I went and one big one which seemed as solid as a rock had the tiniest of gaps around it, so I started probing with the tip of a needle file and there was some slight movement.
It soon became apparent that it was one of those blind knots which needed excavating else it would work loose with the flexing of the bow.
I'm begining to loose count of the filled knots on this stave! You can see it barely shows on the back of the bow, but it is a big cavity which penetrates at least 3/4 of the way through from the belly and threatens to appear out the side of the bow through the sapwood!
Thursday, 8 March 2012
I lay out a centreline along the stave trying to either avoid knots or get them on the centre line. I then mark the half way point and a line to give me about 30mm width there (depending on the power of the bow... but allow some extra for error). At the tip end I'll mark the width as 20mm, despite the finished bow being nearer 12mm wide. This gives room for temporary nocks and sideways adjustments for the string line and to take care of any sideways shift or flex.
It's then a matter of roughing it out on the bandsaw as close as I dare to that profile.
The sapwood on the back will be taken down to a suitable thickness and I'll then mark a rough thickness for the bow (allowing plenty of spare) say 30mm at the grip and 20 at the tip again, running a pencil along whilst a finger is following the back of the stave helps follow the contours. The excess from the belly is then taken off with the bandsaw. (An axe or drawknife will do just as well but it's harder work)
The previous few posts then get me to where I am now, I can't use the spokeshave much now because it snags and tears on the knots of the belly, it's not so bad on the sides as I work the bow down keeping a roughly square or rectangular profile (this make measurements easier)
At this point it looks like a roughly tapered bit of 2x1".
Here are some figures to show how it progresses. (I'm only working on thickness)
Roughed out thicknesses, as measured
29, 28.6, 29.1, 25.4, 22.8, 18.7, 16.5
Now you can see it's a bit fat near the grip and a bit thin where I've been working nearer the tip on that knot. Looking at one of my bows I think 25mm is a reasonable thickness at the point 6" from the grip and experience tells me that a taper of about 1.5-2mm every 6" along from that is about right.
So I write a list of dimensions starting from the centre (which I leave for now) and then to 25mm and 1.5 down after that. This gives
29, 25, 23.5, 22, 20.5, 19, 16.5 This ties in reasonably with the first figures near the tip.
I then work on the limb with a rasp starting at the point 6" from the grip and bring it down to about the right dimension. Here are my measurements after this exercise.
29, 25.1, 23.0, 22.9, 22.6, 18.6, 16.5 You can see I've not been too obsessive about it, but it's a lot closer. This is just the start and it will get worked down once it's on the tiller. As each area is rasped down it's blended into the adjacent areas you rely on eye and feel to keep the work even.
Hopefully the bow won't be too weak or have any nasty weak spots now. I've got to do the other limb, file some temporary nocks and get it on the tiller.
Working it down like this has allowed some of the knots to fall off the side or belly of the bow which is a relief! The pic shows how it looks like a bit of 2x1, the knot just about disappearing of the edge and a small pin knot dead centre. The width of the bow will get reduced a bit later on and the belly rounded.
Sorry if this has been a bit long winded, but hopefully it's useful.
Where I've now narrowed the tip a bit more there appears gradually less and less of the original sapwood, making the patch look a tad thin (viewed from the side of the bow).
Should I take it off and re do it with a thicker longer patch which has been curved to match the parent wood, or is this just overthink?
After all the tip shouldn't do much flexing and there's not a lot of leverage just 4" from the tip. Does it look right?
It's doubtless stronger than it was before, but does it meet the standard I expect of myself?
All I can do is listen to the little voice in my head, there's no shame in taking it off and doing it again, but there is is shame in watching it smash or thinking it wasn't quite right.
the only real answer is to press on and see how it develops.
I've been thinking about this as I write and it would actually be difficult to make a patch much thicker and longer. It does need to be long to provide a long glued surface, (no good just glueing on a little hump). To make it longer would mean it couldn't have a simple flat join but would need a curved scallop taken out (see dotted line in the somewhat exaggerated sketch), this would need quite a thick section of sapwood and would create a disscontinuity further down the limb where the stresses are greater (the downward arrow on the left of the pic). Hmmm, maybe I've done ok after all!
This also raises a counter intuitive point.
I have two bows to make, both need to be about the same length and draw length, one is to be 55# and the other 65-70#. I've started working on the sister stave (from the same half a log), now should the one with this knot 4" from the end be the higher or lower draw weight?
You'd think the lower draw weight bow would be safer with the knot in it, but conversely the higher draw weight bow can be made a tad wider at the tips giving more sound wood either side of the knot.
Ah the joys of bowmaking, frustrating, thought provoking, but fun. No paperwork, just thought and feel, not necessarily any right or wrong answer, just different ways of getting round the problem.
You can see why I work in short burst and actually writing the blog helps crystallise my thoughts. Anyhow, I hope this all makes some sort of sense to you.
Tuesday, 6 March 2012
Monday, 5 March 2012
The nasty knot near the tip of one limb has me worried.
The knot is going to be about half the width of the limb and I don't want to risk it snapping.
The belly is good and sound, I've drilled a small hole through into the pocket of black unsound wood in the core of the bow to help cleaning it out.*
I'm not too worried about the compression (belly side) but I don't want a big weak area in the sapwood which is waiting to snap.
A while back I patched the back of a Yew bow which had a tiny lift in the sapwood so I decided to use the same ploy (See 31st May 2011). By flattening the area with a rasp I can see the extent of the knot better and I can the fill it with yew dust and epoxy, drill and peg it and then finally overlay a sliver of sapwood about 3-4mm thick taken from an off cut of the same wood.
This should strengthen the back and give me confidence to make the tips of the bow a more usual profile rather than leaving a ton of excess wood which would make a pretty feature but rob the bow of speed.
You can see in the last pic, I haven't removed all the sapwood as this would create a discontinuity and a weak point. I've also flattened along to the pin knot on the left as I though I may as well patch over both. (I've taken off a little more since that pic)
*The hole through from the belly side also allows the epoxy and Yew dust to squeeze out as it's rammed in from the other side, this shows me that I've got it packed well in and avoids any air pockets.
PS. I posted my parcel today, The lady helping on the touch screen pressed 'Retail and Lottery'... clear as mud! She agreed the system was bonkers.
Sunday, 4 March 2012
To start with, the Post Office has installed a system whereby you use a touch screen, take a ticket and wait to be called.
The touch screen system is so poorly designed they need someone to hover around to show you how to use it.
I stared blankly at the options on the screen.
"What do you want to do?" the chap he enquired. (Of course he could have been actually serving, had it not been for the silly touch screen and ticket system)
"I want to post this to America" I responded with a sigh.
"That's counter services" he said...
How am I supposed to know how their new system categorises posting something to America?
It struck me as change purely for the sake of it, probably dreamt up by some fatuous marketing man who's never posted anything in his life. And isn't everything counter services, as they are all dispensed at the counter?
A classic case of presentation over content and complicating to the point of uselessness.
Eventually I get summoned to the counter where a very pleasant and helpful lady explained that I couldn't send anything that is pointy or has feathers... Hmmm, that pretty much rules out the arrow then doesn't it?
Anyhow, I shall send it on Monday, with specially padding over the point of the arrow and the fletchings replaced with paper ones.
Presumably they are worried about bird flu.
I shall make sure I state its a 'decorative model' rather than a small weapon!
click... Grumpy mode OFF
It's been raining all day, which makes a change as we haven't had any decent rain for about a year! Rather than moping about indoors I went out to the garage and roughed out another Yew stave, it's not as bad as I feared and it's 72 1/2" long which hopefully will be fine. I took care to run it through the saw carefully leaving some spare width. I don't want another one going bang on me.
First pic shows the overall stave on it's knotty side. The sap wood has been thinned on half the stave (nearest the camera)
The pics show how I've been reducing the thickness of the sapwood. I'm letting the draw knife split if off in great swathes, it's easy to overdo it and I've cut it a bit fine near a couple of undulations, these have been marked in pencil with 'LEAVE' pretty self explanatory.
The nasty knot is about 4 inches from one end, hopefully I can fill it and leave the tip of the bow fairly rigid. On a decent length stave I'd just lop off the top and shift the bow down in the stave.
Friday, 2 March 2012
I haven't re-weighed the draw weight as it's tricky to read accurately, but it's round about 10 pounds.
The arrow penetrates 4" into my target. It kicks a bit left as it's a tad stiff for the bow.
I can't be bothered to make up another arrow, but I can imagine it would go pretty fast and far.
I once made a tiny miniature crossbow pistol which could shoot a 1 1/2" bolt half the length of a football field! It was so light I could shoot myself in the belly with it and barely feel it if I had a thick shirt on. the bolt had a little bit of thin wire soldered round the tip for weight and two paper flights with the trailing edges kicked up a tad to make it spin.
I shall leave the bow strung as it's a right pig to get the string on it, and it's for decoration really. I'll pack it up and post it at the weekend.
Having had a bit of a break, I'll have another look at my stash of staves.
Miniature Yew bow