Friday, 30 November 2012

Paper Crossbow Bolt

There was some discussion about the spine of arrows cut down for use as crossbow bolts.
I offered the opinion that it didn't matter as there is no archers paradox and the mechanical release exerts no sideways force on the bolt.
One guy Joe said this was 'Dangerous advice' which rather incensed me so I set to and made a crossbow bolt from a sheet of A4 printer paper!
It's ordinary printer paper rolled up to be a tube 3 layers thick glued up with UHU glue.
My first attempt was just 2 layers and only glued along one edge, it was too delicate to handle and stick a point on.
A short plug of 5/16 wooden arrow shaft is glued in each end and my usual 50gn crossbow point glued on, the nock end is carefully shaped to sit into the trigger mechanism correctly. The whole bolt weighs 117gn I haven't bothered with flights as it will be shot at about 5 yards into a small foam target suspended so it will swing and hopefully absorb the impact without damaging the bolt too much (assuming the bolt ever gets that far)
I asked Joe what he thought the failure mode would be and he said buckling, well in my opinion it would take a huge force to accelerate a tubular aluminium arrow fast enough to buckle it.
I think we would all agree that a full length arrow made of 3 layers of paper wouldn't survive being launched from a 50# longbow.
Will the bolt survive being shot from a 50# crossbow?
Watch and see!


Monday, 26 November 2012

It Lives!

The repaired bow is now on the tiller and flexing.
I put it up on a low brace height and tentatively flexed it back to about 45# which you can see in the video.
The tiller still looks pretty good and a little rasping to blend in near the grip and some general scraping has now got it back to 50# at 30" from a full brace.
It looks very nice and being shorter has a more pronounced curve.
Obviously there is a way to go yet including plenty of shooting in, but it's looking promising.

I've had a great day so far, the Mother of Pearl arrived, lovely 3mm thick blanks, small but good quality, should be enough for at least half a dozen arrow plates.

Best of all I got got a letter from the council approving my request to cut a Yew limb, see this post:-

Over the weekend, my dust extractor suddenly gave up, it tripped the circuit breaker in the garage and smelled of burning insulation. It was bought 7th December last year so should still be in warranty, a few fruitless phone calls and a trip to Screwfix started the wheels in motion to get it replaced. You can't beat talking to people face to face, the duty manager in Screwfix was a very helpful young lady, who phoned through on a direct line and got things moving. I got a call from the technical people this morning and once I'd explained what had happened they said they would just replace the main part and I'd get a call from their people later in the day to arrange delivery time.
Fingers crossed the good vibe lasts.

Sunday, 25 November 2012

Clout Shoot and Repair pics

Glorious sunshine this morning so I went to the Clout and Roving marks shoot at the club.
The clout was a slightly non-standard event with the flag at 160yards for the big bows and two shorter clouts (120 and 80) for the others. My first 6 arrows were way left as we were shooting towards the sun and once the arrows got above tree height they were hit by a brisk crosswind. After that I got my eye in and made sure I shielded my eyes so I could watch the arrows down onto the flag. I did ok generally getting 3 or 4 scoring arrows (in a fairly generous scoring circle, 7.5metre radius). We were shooting 3dozen arrows and on the last end (6 arrows) I finally got one closest to the flag (scoring 5). I'll have to check on the club forum tomorrow to see how I did.
I was tiring a bit so I didn't stay for the afternoon. I got home to do a bit to the bows, starting to blend in the patches.
You can see from the pics, the stages of the glue up and the side, back and belly views of the roughly blended patches on Brian's bow.
On Bob's bow (lower bow in top left pic) you can see the new belly patch is much more substantial and that knot doesn't extend past half way through the limb now. It makes me more confident about continuing the tillering.
Obviously there is still plenty to do on both bows but they are beginning to look good. Fingers crossed I don't get another disaster.
Re-Tillering Brian' out to 31" will be a bit nervy, but if I worried too much I'd never do anything...just hope someone doesn't creep up behind me and burst a paper bag while it's on the tiller!
I've had to ask my Brother for some more of that nice red leather, as it was my last decent sized piece, I want to make the bow as good as it was before or maybe even better, I take the broken splice as a personal affront, which hopefully I can put right.

Saturday, 24 November 2012

2nd Stage of Repair and a Dilemma Solved

The back patch has now been glued on and wrapped with rubber strapping. The patch is actually made of the strip of sap wood sawed from the back of the bow when it was first glued up as a stave so it will match perfectly.
It will take at least 6hours for the glue to cure in a warm room, so in the mean time I've been working on Bob's bow, which has now been braced and is coming back nicely.

Bob's Bow:-
You can see a fair wiggle on one limb, I've drawn a straight line down the side of the limb to help me see it's true bend as it's flexed on the tiller. Without that line the downward dip near the end looks like a weak point whereas in reality it was actually too stiff and not bending.
My dilemma is that as I'm reducing the thickness of the bow, the belly patch I did at the outset is now in danger of becoming rather thin. Ideally I'd like the bulk of the patch and it's glue line to be about 1/3 of the way into the bow.
I imagine the thickness of the limb acting in thirds, with the back 1/3 under tension, the belly 1/3 in compression and the central 1/3 having a fairly easy time of it, which is why I want any discontinuities or the main areas of glue lines in that middle 1/3.
The pic shows how the patch barely overlaps the knot at its right end.
In view of the problems on the previous bow, I think I shall rasp off the patch and re-do it. It often happens that filled knots and problem areas actually disappear as a bow is reduced in size, this just happens to be a case where, it hasn't disappeared and I think it needs improving. Being half way down the limb a failure would be catastrophic and all my work would be wasted... so better to do a bit more work now.

It's now Saturday evening and I've been busy all day. I re-did the patch on Bobs bow, that's now strapped up and curing.
I've unwrapped the back patch on Brian's Bow and rasped it roughly to shape, looking good. I've now glued on the belly patch and that will cure overnight.
I'm hoping to shoot tomorrow, so I should get some more pics posted on Monday.

Friday, 23 November 2012

Splice Repair Progress + Update

It's always difficult to try and analyse a break or glue line failure unless there is an obvious problem.
There was no such obvious fault so this time I am just being ultra careful.
I've mixed the glue using Highland Spring water which is very pure and not full of dissolved Calcium salts like the stuff I get from the tap. I allowed the glue to rest after mixing to get any air bubbles out of it, I didn't glue it up last night in case the temperature dropped too low and I took a lot of care jigging it up to be held firmly in alignment but without undue clamping pressure.
As one of the guys on Primitive Archer put it, too bad a fit can cause a failure or too good a fit, clamped too hard can cause a failure!
I also put masking tape around the joint to retain the glue as it was being pushed together and strapped up with rubber strip. As I bound it there was a nice ooze of glue as the excess came out. In the pics, you can see the repair to the pointed part of the splice where I've patched in a piece of Yew (from the same original log) taking care to keep the grain lined up. This will all get shaped in once it's glued up and then a belly patch added to give the correct handle bulk.
You can also see the dry assembly on the jig checking it all fits, then the final glue up.
Note I've not bound it up with too much rubber.
All I need now is some patience.
Once this is glued up I can look at a sapwood back patch over the splice to build up the grip area.

Update:- 8PM, I took of the wrapping and the splice looks good and solid, the limbs are nicely aligned. I rasped the belly down to blend in the two limbs and flatten and area for the belly patch. I did the same on the back and was just about to put a coarse belt back on the belt sander to clean up the two flattened areas, when the litle voice in my head said time to quit while I was ahead, don't rush it.
I'm pretty confident now.
Getting a 31" draw from a 71.5" nock to nock bow should be making it work pretty hard, but my old Yew bow has done it and that's heavier draw weight and about an inch and a half shorter.
mustn't count my chickens before they are hatched.

Tuesday, 20 November 2012

Damn... It Smashed in My Hand

The Splice gave way in my hand, it may be repairable, but it will loose an inch or two. I need to find out why it failed.

I'm not a happy bunny.

I've had a look at it and I think it is repairable, the limbs are fine but i will need to re-make the splice. I think the break started at the point of the splice on the back of the bow, maybe the joint was a bit tight there and had squeezed out the glue leaving it dry. Tricky chap glue, don't want a thick glue line, but nor do you want it all squeezed out and dry.
I shall repair it and instead of building up the back with leather beneath the grip I'll add a sliver of yew sapwood, this will improve the stiffness at the grip and also the ability to handle the tension.
I'm a bit aghast that it gave way as I've seen a 170# warbow with a similar splice.

I've re-cut the splice and it looks good, the bow is now 72" tip to tip which is ok. It will need a small belly patch at the grip to make up thickness where the thickest part of the limb was removed, Hopefully this will mostly be under the grip.
The centre line will shift slightly too.

Brian's Bow Detail Pics + Progress on Bob's

The bow is all but finished now, it just needs more Danish oil and a bit more shooting in before a final check of draw weight and adjustment if necessary.
The cord I bought online is excellent, I got two types and went for the braided nylon which, when waxed is excellent. It has a tiny bit of stretch, is a good thickness and sets the leather grip off nicely.
It's hard to get good pics of a bow as it's an awkward shape, but the pics give some idea. I like the detailround the grip, where the edge of the splice is visible and it echoes the shape of the arrow plate. The slight miss match in the sap/heart boundary adds to the effect, you then add in the reddish blush of the remnants of a knot and there is a lot of interest there. There's another knot remnant by the bottom nock, all in all I'm pleased it's turned out so pretty.
Here it is at a full 31" draw.

Meanwhile I've been tinkering away at Bob's bow, the wood is more challenging as there are some serious dips and swoops in the grain, the sapwood is being taken to quite thin in places, but overall it's taking shape and almost flexing to brace height. Some of the problems are becoming less evident as the bow is reduced, but it's a slow process, it should have bags of character when its finished.

Sunday, 18 November 2012

Bits & Pieces

I shot Brian's bow last weekend, it was very smooth, drawing it the full 31" was tricky and resulted in my anchor point being much lower and almost on my shoulder. I'd made 4 nice new arrows using the full length of the shafts and due to the low anchor point I shot the first one straight over the target and lost it in the long grass... damn.
Shooting for distance, it cleared the 180yard mark by about 10 yards which is about right and not bad for a 50# self bow.
I've been finishing off the bow, the horn nocks are done and one knot near the tip has all but disappeared leaving a nice little feature. The tips are much slimmer and it's looking rather smart now.
Finding some decent Mother of Pearl on line was a struggle, most of it is rather thin (about 1.5mm). I contacted one supplier who didn't show the thickness, they said get back to me...
Sure enough, the next day I got an E-mail saying it was 90mm thick... hmmm the perils of the modern world where people don't take the time to actually understand what they are talking about. I don't s'pose the biggest giant clam in the depths of the ocean would yield mother of pearl that thick, I said that was nonsense and haven't heard back (quelle surprise!), maybe they meant 0.9 mm, what's in a few decimal places eh?
I managed to find one last piece amongst my odds & ends which has made a handsome arrow plate, which I've let into the Yew, but I really need to find some more, maybe I'll have to trawl the antique shops and charity shops.
The leather grip is done, but not stitched, I've been trying to source some nice thick waxed thread, I've ordered a couple of different types in black, one of which will hopefully set off the red leather nicely, these details can make all the difference.

While I'm waiting for the thread to arrive I've picked up Bob's bow, it's still barely flexing and now I've got the other bow for comparison I can see I need to take a fair bit off. This is good as it's allowing me to further reduce the sapwood.
I can't be bothered to take any pics today, I'll wait til it's all done (what a tease!).
The sun has been out and I've been climbing up the Cherry tree in the garden and lopping some off the top, it's funny, but I feel much more secure up a tree than I do up a ladder.

Saturday, 10 November 2012

Caramel and Cream & Reversing on the Tiller

Brian's bow is now getting smooth and supple, it's back to 50# at 30" now, I've been straightening up the edges, slimming the tips and taking a tad off the last 1/3 which is now beginning to bend nicely. At one point I thought I'd over done it and made the lower limb whip ended, but a few strokes of a medium rasp at mid limb and a bit off the upper limb had it back to looking great and had given me another inch of draw length. Teasing back these last few inches can be tricky when striving for the perfect curve. It's easy to take too much off at the tips as a few strokes of the rasp is insignificant at the fat end of the limb, it is rather a lot when you are down to less than 15mm thick at the tip.
I've been going over the limbs with a cabinet scraper and 120 grit wet & dry paper removing all the tool marks and it's looking rather pretty.
I couldn't resist giving it a first wipe over with Danish Oil, wow, the colour of the grain shone out and the heart/sap wood suddenly looked like caramel and cream. You can see the difference from the previous post, of course, this isn't the fianal finish, it's just a first wipe to show up any marks I've missed.
Spot the slpice in the lower left pic, you can also see the reddish blush from the remains of a knot.
I'm making up some full length arrows so I can shoot it at the club tomorrow. It's already had about a dozen or so of my 28" arrows and shoots fast and true even with my tillering string with it's metal toggle in place!
Must press on and make a string too.
Once it's had a few more arrows through it I'll make any final adjustments and think about horn nocks, grip and arrow plate.
I've made a string and checked the draw weight and length, it's about 50# @31" difficult to read it accurately .
It was looking a bit whip ended on the lower limb so I carefully checked the bow was supported at the centre and the string was being drawn one inch above that (in line with the arrow pass). I reversed the bow and took and it looked much better. The pictures illustrate the surprising amount of difference and I've added ellipses in 'paint' to help show it up. I shall probably keep the upper and lower limbs as they are in the better view, it would seem daft to insist on trying to adjust the tiller to conform to my previous arbitary choice of upper and lower limb.
Maybe I've just got 'tillering fatigue' but the pic on the right looks much better to me. I'd welcome any comments on this.
Explain More:-
Effectively all that is changing in the two pics is the point on the string where it is being drawn, which is about 2" different in the two pics. This is enough to make the bow bend slightly differently. This is why the technique called string walking is a nasty thing to do on a self wood bow.
As an example of string walking:-
At very short range you could maintain your usual anchor point but draw the string from a point 2 or 3" below where the arrow is nocked, thus that the back of the arrow is aligned with your eye, and yet you have your usual anchor... great for easy aiming, not so good for the health of the bow if its made of wood.

Friday, 9 November 2012

Temporary Nocks and String Line Adjustment

The work I've done after adding the temporary nocks has got the bow looking much straighter now (compare it with the pic on the previous post). Some of the apparent sideways bend was more about the sides of the bow not being straight, this happens due to a variety of factors, say a knot which is being rasped away to fall off the side of the bow or maybe the spokeshave snags and tears a bit and an area is filed/rasped down to remove the rough area. The wood also moves a bit as it is worked down and exercised. I held a straight edge on the side of the bow to mark any high spots which were soon reduced with a spokeshave.
The pics show the improved string line, the temporary nock and a filled knot which has all but disappeared.
the sapwood on the back of the slightly darker upper limb is also shown. Doubtless some armchair critic will say the back of the bow doesn't follow a single growth ring, but you can see the ring 'violations' run along the bow. The whole 'follow a growth ring' this is IMO a bit of a myth which has been imported from the USA where they use a lot of Osage which has much more distinction between the rings and it is very important to follow a ring as the thinner (winter?) rings are much weaker than the harder thicker growth.
It makes sense to follow a ring where you can and try to keep any 'violations' running along rather the across the bow, it's an aim rather than being vital, and you have to sometimes let the stave dictate what you do rather than going 'by the book'.
Where the rings don't fall in line with the back of the bow I've tried following a ring and having a sloping back and doing what I've done on this bow. Both methods work fine, but the former is a lot more work as the belly ends up following a weird profile too to avoid the bow going sideways. It's tricky to get a good picture of the grain on the back as it's so pale.

The bow is now at virtually a full brace height and has come back to about 25" at 45#
I hope to get if to full draw tomorrow, with some pics of course.

Update:- 50# @ 28" see pic.

Thursday, 8 November 2012

Brians Big Bow + Update

I usually avoid names to protect the innocent, but there has been some confusion over the two bows so I'll call 'em Bob and Brian, which may or may not be their real names... or maybe it is?...spooky eh?
Anyhow I'm pressing on with Brian's bow and it's now at a low brace height and pulling about 19" at 45#
The target weight is about 48#, but I'll make it 50# initially to allow for settling down and finishing, for the moment I'm not going over 45# untill I've got it nice and even.
The upper (right) limb is a tad stiff, and both need to work more in the outer half / two thirds.
The main thing is it's trying to twist and bend slightly sideways, I can't cut the nocks much further to the desired side (nock nearest the camera needs shifting left), so I'll resort to an old trick and glue on a temporary tip overlay  and file the nock groove in that (and maybe fill the nock groove on that left edge with epoxy and Yew dust). This will allow me to effectively shift the tip over by about 1/4" to help it all align itself.
Bear in mind the tip will be reduce to a point like a sharpened pencil when it comes to fitting the horn nock, so I've actually got plenty of wood to spare.
I can also remove a little from the left upper edge of the belly to encourage the bow to bend that way.
You can see that the bow is almost a square cross section at the moment so it doesn't really have any great desire to flex one way rather than the other. It needs gentle coaxing, several small changes will pull it into line.
I had a contact from a guy a while back with this very problem and with a bit of advice he sorted it out. It can be rather panic inducing the first time you meet it.

I could just press on regardless and at a higher brace it would find it's own plane of bending, but that might be slightly skewed, much better to get on top of it now.
The potential for sideways bend is much less on flat bows (like my primitives), shorter bows or higher draw weight fatter bows. The combination of a moderate draw weight on a long bow makes it something to watch out for, but conversely it should make a very smooth shooting bow.
I shall try to give it that slightly medieval look with the limbs tapering fairly late in the last 1/3 rather than more evenly along most of the limb.
The whole tillering process can run away with you, and it's about now that I need to slow down and get it really right before moving on.
You can see the sapwood layer is much thinner now and the heart/sap boundary is looking good.
I said the right limb is stiff, that's one of those things that can send you round in circles and cause great confusion... the right tip is pulling down lower than the left one, so surely it's weaker??? Do you see the dilemma? The way I look at it is to imagine what happens if the right limb is rigid, the bow would tilt down at the right tip pivoting on the support like a seesaw (teeter totter if you are in the US) and the more you weaken the left limb the more it will flex up and let the stiff right limb pull down. I can see why some people like to clamp the bow, maybe it makes it clearer, but I like to do it this way. Of course early on in my bow making I got it wrong, reduced the wrong limb and made the problem worse and worse until I worked out what was happening, it's the lessons like these we remember most.
Anyhow, progress is good and I'll be posting quite a bit in the next few days as I hope to get it shooting a couple of arrows by Monday with a bit of luck.

Update:- Thursday evening.
I've shifted the nock and slimmed the tip considerably, it's now bending much straighter and is coming back to about 23" at 50# from a reasonable brace height. The curve of the bow is better too as I've also started rounding the belly as part of the work to help it come back true.
Now it's time to get the back cleaned up pretty much into it's final state and get the limbs back to a lovely even curve as it slowly get back towards full draw.

Monday, 5 November 2012

Fancy Knot Filling and Flexing the Longer Bow

I've been working hard all weekend and even put up some shelves, I need to go to work tomorrow for a rest.
The shorter longbow had one final knot to fill, I thought it went across the corner of the bow in the heartwood, but then I realised it went towards the back of the bow and disappeared into the sapwood showing as a bulge and a tiny hole. I cleaned it out and tried a new trick for plugging it, I used the heart wood from Yew twig (from the branch I cut at the churchyard) which has circular grain and so looks like the original knot, except now it's firmly glued in place with no powdery stuff round it making it loose.
Although the Yew for the plug was only cut a few days ago it has effectively seasoned by being rasped down to a few mm diameter and left on a hot water pipe.

The longer bow has had about an inch cut off each end making it about 75" now, I've re-drawn the centre line and narrowed it slightly over the last third to make it straight and true. The belly has been reduced, but it is still only flexing a few inches at 45#.
The video is the longer of the two bows being flexed.
I don't want to remove too much heartwood, so I've been carefully going over the sapwood back tidying it up, reducing it a little and bringing it down to follow a growth ring where possible. It certainly is beginning to feel like a bow now. This is the point where it's tempting to rush ahead and try and get it braced, but it's really the time to take stock, make sure it's a nice even taper and ready for the serious work. I like to be able to see a little flexing down somewhere near the grip when the full draw weight is applied, this shows that when it's finished the whole bow will be working to some extent.
I can now slowly get the rest of the limbs working more and the tips slowly working back to brace height. Then its time to shorten the string and slowly tease it back to full draw by slowly removing wood from the belly.

I've done a bit more on both bows, reducing the sapwood  to a more even layer and following a ring, they are slowly becoming more handsome and elegant. The shorter one has a bit more character, the undulations are beginning to show nicely on both bows and some of the problem knots are falling off the side of the bows as I slim them down..

Sunday, 4 November 2012

Variability of Yew

I've been rather busy this weekend, I had a visit from the chap for whom I'm making the shorter longbow. It's good to meet as we could discus nocks and other detail I could see him shoot and we gave the various bows an outing, it reminded me he's left handed too.
Next morning I was off on a long drive to collect a Yew log which I'd spotted back in April on a Hampshire estate, I'd got in touch with the head forester at the time and he located the tree and cut the limb for me at a very reasonable price considering the work involved in getting it out.
You can see the branch in the middle of the tree sticking up almost vertical. You can see it's a bit of a way off the ground, and having felt the weight of it I now realise how foolish I was thinking I could have managed to cut it myself.

I met up with him and we had a good chat about the forest, Dutch Elm and Ash die-back disease etc. He was really interesting to talk to and he said he'd keep an eye out for similar pieces of Yew for me, if they do any work on Yew trees.
The Yew log looks superb, but the heartwood sapwood boundary is rather indistinct and there isn't as much heartwood as I'd hoped. (See the end of the log in the pic of it on the bandsaw). There is still two bows in it, but I'd been greedily hoping that maybe I'd get 3 or 4 ( I hadn't realised it was so oval in cross section)

When I got home I went to a local churchyard where the vicar and church warden had agreed I could cut a skinny Yew branch.
By contrast, I can touch my finger tip to my thumb round the middle of this branch but it is nearly all heartwood!
The vicar was there working in the vicarage garden and as we were chatting I spotted a second similar branch in the adjacent tree, he said I may as well have that too. I could scarcely believe it, this one was even better, the heart wood was dark blood red and there was just a thin line of sapwood around it.
I put a hefty donation into the church funds and wondered if maybe I should invite the vicar on all my Yew hunting expeditions.
The skinny branches probably won't make a classic longbow, but will certainly make a primitive or maybe a branch style longbow. There is an Eastern European guy on Primitive Archer goes by the user name 'Druid' makes superb high draw weight longbows from branches, often full of knots, but real works of art, they tend to be flat bellied and semicircular back.
I just found his website, it's in Croatian but the pics on the home page are great and will cycle through.

Note the different bark on the logs, I don't know what the significance is as both Yews were really old, not just landscape yew.
I've got the big log cut up already, it was getting near the limits of my bandsaw and was a bit of a struggle. First I took a slice of sapwood off each side (they may come in handy for backing bows) that made it a bit lighter and also easier to mark up and run through the saw for the main cut.
It was then cut down the middle to give two substantial staves.
After wrestling with logs all day, I slept like one.
This morning I'll paint the ends with PVA and store them on my shelves for a year.
I'll be able to get back to the longbows now and hopefully get a picture of them beginning to flex on the tiller on Monday.
While I was down south, I met up with my brother who opined on the Yew log and gave me a laminated stave from a boat builder friend of his who also made some bows, he's now is in his 70s and felt he'd never get round to finishing it. It's Lemonwood backed with Hickory, two woods I haven't used so it will be interesting to finish it off. John the boat builder had also passed on some archery books.