Thursday, 28 February 2013

Yew Longbow More Heat

I got the bow trimmed up to about the right dimensions and cleaned up the back. Putting it on the tiller it felt a bit under powered so I got it braced and tried it. 50# at about 26".
I'm aiming for 55# at 28" so I was a bit worried, it looked good on the tiller but looks more like it should be coming back to 20" not 26".
I cleaned up the back to a decent finish and rounded the belly, pulling it to 28" and it was under 50#.

Not good enough, must try harder! Some of the deflex had come back, so I've decided to re-temper the belly and get a hint of reflex into it this time.
I've put 4 layers of masking tape over the sapwood and strapped it up  with an inch or two of reflex. In the smaller pic you can see the limb nearest the camera clamped up with some reflex while the far one still has some deflex
Where I'm heating it I've clamped a couple of off-cuts of wood to keep the heat from the sides of the bow, it also helps to channel the hot air along the belly aiding even heating. I've got one limb done now and I'll unclamp it and do the other tomorrow.
Update:- Ive had a look and the tempering seems to be better this time, the belly is darker, and having unclamped it, there was less spring-back this time. I might do the other limb tonight, so it will be re-hydrated by the weekend.

If I can get anything over 50# at 28" I'll be happy, I don't want to shorten the bow any further, and chasing draw weight too much can be a self defeating task in my experience.

The bow is fairly chunky in cross section with the pith line showing on the inner 1/3 of the belly, it shows how little heartwood I had to play with. I think it's going to turn into a fine bow, it'll just take some more work.

Meanwhile I'm messing about with the bonkers bow, which is actually shooting now! It's symmetrical about the centreline, e.g Big long narrow grip section so the working limbs end up being about the same length.

Monday, 25 February 2013

Straighter

The stave has been unclamped now, it hasn't taken the bit of reflex I'd hoped for but it's pretty much straight now in both directions so I'm pretty pleased with that.
As I took the straps off it sprung back a good deal and I was a bit worried it hadn't taken out the deflex on the second limb. Looking closely, it's actually the first limb that still has a bit of deflex, mind I didn't bend that one quite so much.
It's tricky heat bending yew as it can have a good bit of spring back when you're bending a fairly thick section.
If you compare the pic with the one from a couple of posts back you can certainly see the difference. You can also see the temporary nock filed in for tillering.

I got a lift up the club yesterday for the end of month shoot, it was bitterly cold but most enjoyable.
The three of us shooting were gong round in an un-spectacular fashion until we had a break and started round the 15 targets for the second time, we slowly seemed to settle into a groove and suddenly we were smacking 'em in first arrow. A couple of times we had 3 first arrow kills with all 3 arrows touching it was uncanny. I always feel it better to start poorly and finish well.  The last shot was a tiger at about 50 yards? we all managed to hit it which was better than first time round.

Update:-Now the stave it's straighter and it's roughly to size i can really look at the problem areas.
It's pretty clean really but there is a knot near one end. I had a chap with the guy I'm making it for yesterday and he's a tad shorter than me, I'm 5'10" so I obviously don't need the full 74" of stave I have at the moment.
So I took the opportunity to kill two birds with one stone and sawed a good bit off one end leaving the knot hanging off the tip and beyond where I will re-cut the temporary nock.
On the one hand it's good to have some spare length, but if it's not taken off at some point you find the bow has progressed so far you are reluctant to shorten it and it then is a bit longer than you'd really wanted.
The other pics show a couple of knots, one on each limb, they aren't big enough to be a real problem, but you can see how loose they look, with that ring of black manky stuff round them (presumably that's sort of rotted bark?). So I'll pick 'em out and peg 'em... funnily enough, they are pretty sound, I picked out the ring of black, but it only went in about 3/16" so I've just filled it 'em with epoxy sawdust mix.

I've run a taut string down to create a new centre line too and trimmed it up around that, about 30mm wide for 4" either side of centre than tapering to about 20mm at each tip. That sill leaves me a fair bit of wood to play with.
This afternoon I'll tidy the back a bit and get the belly down a bit, check it's an even taper and hopefully get it flexing to about brace height on the tiller.

Saturday, 23 February 2013

Feel the Heat


There are flecks of snow falling, so more heat treating and bending is about the only sensible job in the garage.
I've done the other limb of the longbow stave which is looking good .
While the first limb was clamped up yesterday I tidied up some of  my Yew, I ran one half log through the band saw taking off the manky side as a long triangular offcut. I always look at the offcuts and save anything useful.
This piece was almost the size of a bow but it had some bad deer damage through the sapwood, nasty knots and some very skinny parts (2nd pic)
It seemed to be challenging me to turn it into a bow. I couldn't resist and quickly shaped it with bandsaw and spokeshave. I flexed it a bit and there were horrible cracking noises as the bark started to pop off.
Well I couldn't resist I de-barked it and saw the extent of the deer damage. I did a sapwood back patch on it  and this morning while the 2nd limb of the longbow is resting after heat bending I've narrowed the grip and heat bent that to bring the tips in line.
I'm just going at it  mad to see if I can getting shooting for the club 'end of month' shoot tomorrow. I'm calling it the bonkers bow, it' just a bit of a joke to see if I can bully a bit of Yew into a bow in revenge for that one whacking me on the head.
Not sure if it's the bow or me that's bonkers.

The last pic shows it cleaned up ready for the sapwood back patch, that last pocket of rot was cleaned out and filled with sawdust-Epoxy mix before the patch was glued on.

Update:- I've done a belly patch on one skinny area, I suspected it was going to be weak and as I pulled it back on the tiller I could see some remaining cambium (the brownish red under bark layer between the bark and the creamy white sapwood) popping off as the weak spot flexed. The flexing also made 3 knots start to come out. That was rather reassuring as it shows my usual caution with knots is well justified.
I've filled 2 of the knots, the 3rd will have to wait, so I can't get it shooting for tomorrow. I think it may have the makings of an interesting character bow.
Where the belly is rather triangular from the way it was sawed, I've sort of echoed that shape along the bow. It will be interesting to try a different belly shape. There are some South American native bows which are the same proportion as a longbow but with a much more triangular cross section and a back which is actually concave. This bow has a concave back in some places so maybe I'll accentuate that.
I can't decide whether to shoot Twister of one of my Longbows tomorrow, maybe I'll give my side nocked longbow an outing.

Friday, 22 February 2013

Progress and Heat Bending



The stave is from a skinny log and the centre pith is clearly visible as it's roughed out. I've roughed it with bandsaw and spokeshave. I decided to use heat to take out the deflex  at the outer end of the limbs and introduce a hint of reflex which will probably pull out during tillering, hopefully ending up with a fairly straight bow.
The heat will also be used to temper the belly toughening it up a bit.

Lower right shows it roughed out before the heat treatment/bending.

With small logs, as you work down towards the centre pith sometimes fine cracks will open up, they can look alarming but they are just tension in the stave releasing and they only radiate out from the centre pith and don't go down beyond it. Often you'll see them near the grip of a bow if the centre line is incorporated into grip.

The pics pretty much tell the story, in the last pic you can see the deflex in the un heated limb nearest the camera. The far limb is clamped down and has been toasted for about 45 minutes over it's outer 2/3 along the belly. It's a pretty boring task, but at least it's warm on a freezing cold day.

Thursday, 21 February 2013

Pushed it Too Far


Damn, I should have known when to quit, 50# at 29" was plenty for a relatively short longbow.
But no... I'd shot a few at 30" and taken it back to 55# @ 30" on the tiller.


I'd taken some nice pics and was going for the full draw picture when it exploded on me.
I was a bit shaken, but rather annoyed with myself for getting cocky and pushing it too hard.
Still, better to explode on me than some one else.


Examining the break (lower limb), there is no obvious defect, the sapwood seems to have given way a few inches below the grip. There is a knot through the heartwood further up the break, but that doesn't look to be where it started.

It's a shame as it was looking rather handsome and seemed very fast, presumably because it was working so close to the limit.
As one of the guys on Primitive Archer says.
" If you ain't breakin em, you ain't makin em".
That upper limb (the Oregon one) is still Ok but having been messed about twice I think I'll give up on it. I might mount up the tips with their nocks as an illustration of horn nocks, I don't think I'll be able to take 'em off and re use them. maybe I could wear 'em as ear rings (joke).
Hmmm, not a happy bowyer, but onwards and upwards. I'd called it as an experimental bow, just a shame the guy at the club didn't get to try it, although he's avoided the whack on the head!

More Cheery Update:-
I've started on another stave which has had a year seasoning it was from Shaun at the club and hopefully there's a longbow in it.
See this post http://bowyersdiary.blogspot.co.uk/2012/01/yew-logs.html
I've run it through the bandsaw and it looks promising , it's a bit skinny but I've sawn off the excess sapwood, cut down the sides to approximate dimensions and cleaned up the belly to show the black centre pith of the log for a fair bit of the stave.
It's 84" long with a few knots, but with all that length I should probably be able to position the bow with the worst knots at the grip.
The stave has about 2" of deflex, I may add a little reflex over the last 1/3 of the limbs later, but we'll see how it comes along. I prefer to avoid the hastle of heat bending if possible.
The pic isn't very good but it gives an idea of the size of the roughed out stave.

Tuesday, 19 February 2013

Special Relationship Bow



This bow is made from two that exploded on the tiller last year, one was Oregon Yew (the limb that exploded had bug holes in the sapwood) and the other English Yew (rather knotty on one limb), each had one remaining sound limb, these were spliced together just to see how it would perform.

I mistakenly supposed the Oregon Yew would be tougher and better suited to the lower limb which has higher strain on it being a little shorter. This assumption turned out to be false as the English Yew which looked skinnier seemed to slightly stiffer than the Oregon Yew... so I inverted the bow, this made the spliced join appear  slightly off centre.
The join is a bit of a mash up with both back and belly patches to get the whole thing blending together, there's even a tiny addition on the side of the splice to fill a gap (2nd pic down on the left).
It's ended up very deep and narrow at the grip and seeps to shoot surprisingly fast. More pics later in the week showing it drawn.

I've tillered it for a guy at the club to experiment with, he's a big chap and being relatively new to archery hasn't settled on his desired draw weight or length yet. This will allow him to try out a more powerful bow at longer draw before I custom build him something a little special in later in the year.
It's currently drawing 50# at 29" and I'm pretty confident in taking it back to 30" once it's shot in a bit more, I've only shot 30 arrows through it so far.
There's a weird dip on the edge of the upper (Oregon) limb, to counter this quirkiness the English Yew has big knot and dip, originally this was to be at the arrow pass, but is now on the lower limb.

It's fun to do something experimental as it can be tested harder than one might usually dare, in the knowledge that the bow has had a second chance. This begs the question, do I christen it Transatlantic, Special Relationship or Second Chance?

PS. It's this bow that's having the arrow plate inlaid in the previous post.

Monday, 18 February 2013

Inlay tips & Tricks

Here are some pics and a video clip showing how I inlay my arrow plates.
I tried to get a close up video of cutting the cross hatching, but I couldn't get the lighting right and the camera auto focus kept moving about. The still pic shows the detail better. You can see the centre line of the bow marked, and in the big pic you can see how I've cut well inside the base line. This allows adjustment at the pointed end to be done first and then the back edge cut to fit. The inlay in this case is Waterbuffalo horn and is cut with the edges slightly tapered to give a good fit, like the way a cork fits into a bottle.


Once the first layer has been removed it's easy to cut inside the edge to make it deeper and repeat the cross hatching and chip removal.

Old needle files can be ground down to make very useful small chisels for removing the chips and cleaning the bottom of the hole and tidying the edge. A small grind wheel which fits in an electric drill only costs a few pounds and is very useful for making/modifying tools.
The great advantage of these tiny chisels is they are very easy to sharpen, a quick wipe on an oil stone or wet & dry paper with a spot of oil and you can have a razor sharp custom made tool just the right size for your job.

video
The knife I use is an old fashioned craft knife (Stanley knife) but the two halves have been opened up and filed flat so they close tight and grip the blade to stop it rattling about. A scalpel would work just a well, but the Stanley knife gives plenty to grab hold of and room for two hands. I'll hold it steady with one hand and then use the thumb of the other hand to apply a controlled leverage for a powerful cut which won't shoot off cutting across the surface of the bow.

The final pic shows the inlay having been filed to be a good fit into and nosed into the hole with it's back edge sticking up. The knife can then score an accurate line for the back of the hole ensuring a snug fit.
I like this shield shape for an arrow plate. Often they are made with simple straight lines, like a rectangle with a triangle on top like the end view of a house.
To me that looks cheap and is often sloppily done.
I used to do oval ones which are a bit of a pain. The shield shape gives the benfits of simplicity whilst retaining some style. I've seen round ones too, but I suspect these where commercial 'dots' of mother of pearl let into a drilled hole... that's just got to be cheating ;) !



Friday, 15 February 2013

Fallen Elder

I noticed a big old lump of Elder had fallen on to the cycle track the other day. Maybe the weight of snow on it (now all thawed) had brought it down. I went and collected a piece of it this morning. Some had already been cleared from the path. The piece I cut had been growing at an angle, the top face is covered with moss and lichen and has shoots coming out of it.
You can see the wide growth rings and large core of central pith, you'd think that it wouldn't be much good for a bow, but apparently it is.

The pictures you'll often see in books about making bows often show a bow made from the upper surface as this will be 'tension wood' e.g The layer under the bark which becomes the back of the bow will be under tension as it grows and is thus ideal for the back. It is however deflexed.

The main trunk is still there and I may consider going back with my big saw and two wheeled dolly to collect that too. I'll probably regret it later if I don't! See last pic... yup, I went back and got it  as a stave seasononing in the garage is worth two in the woods.

I've rested the log against the car at the angle it was growing, The underside of the log is free from shoots and has a natural reflex if used for a bow.
So which face is better to use? It's not as clear cut as the books would have you believe. Maybe the knots formed by the shoots on the top face could be placed at the grip, but then the lower face is longer and cleaner.
Short answer is I don't know... maybe I can make a bow from each face and compare the performance. Anyhow it will take a year to season, so there's no rush.
Meanwhile I've been indulging in some armchair retail therapy, bought a dozen arrow shafts and 3 doz fletchings from Quicks, a reel of Angel Majesty string material from Merlin Archery and a nice 3" grind wheel of E-bay (only £2.49!). My existing grind wheel is almost worn away to nothing, so I'll take the arbor off that and mount the new one.

I used my folding pruning saw to cut it, it's on the ground by the car.

Thursday, 14 February 2013

Copper Archer Sculpture


Got the copper archer finished, I'll be mounting him on a slice of Yew for a local exhibition later in the month.
There's always the dilema of how realistic vs how stylised.
I like his shoulder blades and the copper rivets.
I've taken great care with the geometry of the bow, the distance from his hand to each bow tip matches up correctly in each position, so the bow has the right ammount of curve for the draw length.
I'll let him tarnish a bit then wipe him over with beeswax polish. I could go for a dark patina finish, but I like the natural finish he's got at the moment. I might experiment on a scrap of coppergiving it a quick wash over with vinegar.

I'll be finishing the Transatlantic Yew and then starting on a stave which one of the guys at the club cut last year.

It's funny, but once you've done something and it's been standing around for a while you can see the problems with it.
His right hand is a bit high and the right forearm isn't in line with the arrow, the nice pinch at the top of his shoulder blades is stopping the right elbow getting up in line with arrow and hand...
So I took off his right arm (that's about the 3rd time it's been on and off) and filed a bit off the to inner edge of the shoulder blade. It looks much better now. I also made the right hand a whisker smaller.
It looks as if his hips should maybe come up a tad especially in the shot from behind, but maybe he just has a big arse!

Monday, 11 February 2013

Catleg, Six spot? Wha'eva


The bow is virtually finished but it's cold and snowing with isn't conducive to a final going out to the garage and working over of the back to remove the odd file mark, and apply more Danish oil.


The light is a bit poor for photography too.
Here are a few pics to show how it looks. The veg tan leather will darken and look better once it gets a wipe with beeswax polish, which will be the final finish.
You can see the lateral waggle and the recurved lower tip have calmed down a bit. The 'six spot' domino pattern caught my eye last night while I was stitching the grip , a task I could thankfully do indoors.
Inlaying the arrow plate was slightly trickier than usual due to the knot.
The knot also accounts for the grip and upper limb being left a little thicker at that point.

It'll have a bit more sheen to it by the time it's finally done, and a better light would have been more flattering, mind it's a pleasant surprise when things look better in the flesh. I s'pose there's a whole advertising industry striving for the opposite effect.

Out of interest, this will give you some idea of the answer to the thorny old question 'How long does it take to make a bow'. I've just been out to the garage 'for a few minutes'. I put a new clean burr on my curved scraper and carefully went over the back of the upper limb taking out the few remaining tool marks, I then went over it with 240 wet & dry. Of course I spotted a few tool marks on the belly too, so I took them out using the scraper, 180 then 240 wet & dry. I finally gave it a wipe with Danish Oil.

A few minutes? Actually it was 45 mins going over one limb which many would have considered adequately finished anyway! So why do it? Ah! When you know there are no tool marks, if you see something untoward you know it needs investigating, even a small dent or scratch is worth knowing about and some fairly big problems can be sorted if they are caught in time.
There is the fact that I enjoy it too, in a slightly masochistic way, it can get a bit tiresome, but the difference it makes is worthwhile and there is the pride in ones craftsmanship. tasks which were once a right pain become  easier and more satisfying. There's the joy in the learning process too, it's the first time I've put a new edge on my curved scraper (check out youtube for how to put an edge on a scraper, but don't get worried if you see fancy expensive burnshing tools, I use the shaft of a big old screwdriver).

Saturday, 9 February 2013

Catleg Bow Full Draw

The bow has now had 60 arrows through it and has had a little scraped off here and there. It's now pulling about 48# at 26 which is probably just about right.
You can see at full draw the ripples and deflex kick in the limb are still visible.
Later I might add a composite pic with the two shots overlaid so the deflection at each point along the limb is visible, but there's tea and toast to be had...
A pic is worth a thousand words.

I've done the composite pic, and was about to jump to half arsed conclusions but managed to stop myself in time.
It would be easy to look at the composite pic and say the left limb tip has moved a lot further than the right, therefore that limb is too weak... Ah but in the words of a well known comedy character yeah but no but.
The way I set it up on the tiller allows it to pivot as the string is drawn back, due to the fact that the bow is supported pretty much central but drawn at the nocking point. If you flip rapidly between the two pics (you may have to copy them onto the desk top) you will see the grip remains relatively static... yeah, but I just said it's free to rock! (I can't have my cake and eat it too). So Is the lower limb weak? Is the whole tiller the lower limb stiff a myth, do I trust my eye rather than measurements? Can I be bothered to clamp it rigid and repeat the test?
Well no, there comes a point where over analysis adds to the confusion rather than clarifying it.
Measurement and analysis is a guide, a tool, same as maths... no good throwing a load of maths at something if the answer doesn't match reality or help your understanding.
One has to remember that the deflection at any one point is very difficult to see, we get the overall curve, but if you try to look at the bend over a 6" section you will be lucky to see anything.
One could always make a bend meter that you can clamp to a point on the limb with a dial gauge that presses on the limb say 3" further along, that way you could get loads of data and plot lots of nice graphs. But why would you? It was all done many years ago by Clarence N Hickman when he made the first scientifically designed bows. If that's what I wanted, surely I'd be shooting a modern recurve.
There is always a tension between buying fancy tools to make the job quicker and easier, but at the risk of destroying the process which I do for the love of it (sobs into mug of tea).

So, whats the conclusion?
I shall do very little, but if I do any more minor adjustments, they will probably be with a scraper and to the upper (right limb), as it is probably just a whisker stiff. Note, this is pretty much in line with what I've been saying earlier during the tillering process. I do have a few pounds of draw weight to play with still as I'm looking to be between 45 & 50# at 26".
Interestingly, If you hold a CD up to the pic you'll see I've pretty much hit my usual arc of a circle tiller and if you compare it to the pics from one of the earlier posts you'll see it looks much better. Sometimes the changes are quite subtle, and going back to the earlier pics allow me to see the changes.

Update:-
I've given the upper limb a good going over with the scraper and shot it some more, it's about midway between 45 and 50 now, I'm reluctant to say 47 1/2 # as you just can't measure that accurately.
It's now had 75 arrows though it and has drawn blood! One of my poor attempts at a left handed shot scored my right hand with a fletching, but at least I hit the back stop.
Just down to the cosmetics now, I might do the arrow plate this afternoon.

Friday, 8 February 2013

Left Handed Testing

Thursday:-
The bottom nock is on the Yew 'Dogleg' bow now (Although I might call it 'Catleg' in deference to my pseudonym). I tried a couple of shots left handed at close range with my tillering string on, but it seemed to shoot a bit sideways. Right handed it shot straight. Now is that me or the bow?

So... I moved the toggle which I use to adjust the tillering string (pic left) down nearer the centre of the string to avoid that causing any weird imbalance and had a careful look at the string line and how the string sat on the nocks.
It was sitting a little skewed, due to the dog-leggedness of the lower limb tip. A bit of work with a round needle file soon adjusted the string grooves in the horn nock. I checked the string line and it looked much better.
This time I shot from the full 10 yards and took care to shut my right eye so I could get some sort of aim. I put my tab on my left hand back to front and managed a half decent draw... thwack... nice and straight in line with my point of aim. I shot another for good measure which hit clean and true. Time to make a decent string and then do some serious finishing and shooting in.

I've had a good day, a guy from the club came over to chat about bows and try a few, he's relatively new to archery.
I don't have a stave suitable for him at the moment, but he's going to give the 'Transatlantic Bow'* I've been working on a home while he settles into shooting.
He'd been to the 3D NFAS open shoot at Avalon Archers which was a great introduction to a big shoot. He's currently shooting a 40# bow but is aiming to eventually get into something a good bit heavier, hopefully I'll have a suitable stave for next year.
He's a big chap and pulled my big old Yew longbow with relative ease and that's about 68# these days so it will be interesting to make him something hefty.
 It's always fun having people over as you get a chance for a decent chat, at the 3D shoots everyone is rather wrapped up in the shooting.
The Chinese repeater had an outing too which is always raises a smile.

My copper sculpture is coming along again, I'd left it lying on the hearth for about a week, and having picked it up again I could see what needed doing. Sometimes it's good to let things sit and mature for a while.

Friday:-
I've made the string and adjusted the nocks for string line and aesthetics.
I must admit I was a tad disappointed with the colour of the top nock, it was a bit plain. The bottom nock in contrast is stunning! I wish they were the other way round, but such are the vagaries of natural material.
The horn is translucent in places and you can see the grain of the Yew showing through.

The bow is still a tad over weight, but as I do the finishing I'll be evening up the limb thickness and minor ripples to give it a sleek undulating look, which may well drop a pound or two.
It still has loads of character, and at first glance rather boggles the mind as that recurved lower tip with the sideways bend looks like it will just fold sideways!
Once you hold it, feel the balance and flex it you can see and feel how it really does all line up and pull straight, then it starts to grow on you as you see the detail.


* That's the bow made with one limb Oregon Yew and one English Yew. I'll probably name it 'Special Relationship'

Monday, 4 February 2013

Horn Nock Instructional (part2)

video videoHere are three brief videos which show the shaping and finishing. When I say 'tile file' I actually mean 'tile saw'.
Note the rasp I'm using has a medium cut one side, fine the other and the edges are flat with no teeth at all so I can guide the edge of the rasp against my thumb without drawing blood!


The still pic show the nock 'finished' just for the purposes of this post, that is to say, I haven't shaped the groove to fit the actual string on the finished bow... well I can't 'cos I've only done one nock so far! The lip at the edge of the groove may be reduced and rounded a bit to make it all more subtle.

videoIf you are wondering how I polish the string groove I use a needle file with some 240 grade wet & dry over it and then finally buff it up with an old bootlace which has been loaded with Vonax compound and is then worked back and forth diabolo fashion. If you check out the video, you'll notice the groove in the bock of Vonax where I've run the bootlace across it to load it with compound. This is my pet 'secret' technique so don't tell anyone ok? You can also just about make out the transition from flat back to rounded back as it approaches the nock.

Horn Nock Making Instructional (part 1)

I've noticed the page of this blog which gets the most hits is the nock fitting tool, I've also had quite a few questions on the topic.

So here's my guide to:-
Horn Nock Making.
Horn Nock Fitting.

Over the last few years I've honed my technique from starting with a vast chunk of horn and trying to shape it before gluing onto the bow.

Now I start with a much smaller piece and generally get both nocks for a bow from one bit of horn, (pic1) this saves on cost and also saves on a lot of rasping, it also gives nicely matched nocks when using the paler horn as I'm using here. The horn looks fairly dark at the moment but you can see the white centre on each bit, and once the scruffy outer layer is taken off and it's polished hopefully well see some nice coulour.
Note the drill I use has the shank cut down, this helps to keep it rigid and centred as some cheap wood bits wobble about like a drunkard and centre differently each time they are put in the chuck. The drill is just a 16mm flat wood bit (they are V cheap) the flat cutting face is ground away to make the shape in the pic. I used a grind wheel mounted in my pillar drill.

(Pic2) shows
the drill offered up to the end of the bow, note I've stuck masking tape onto the back of the bow and marked a line 6" from the nock. This allows me to cut the final nock groove in the horn in the same position as the temporary nock.
Pics 3 & 4 show the horn against the drill and the end of the bow limb, this is going to be the top nock which is slightly longer and fancier than the bottom nock which has to withstand more bumps and abuse as it contacts the ground.

Once the nock is drilled (see the video) the tip of the bow is rasped to a rough point. I rasp back and belly first to a sort of wedge, holding the drill up against it for comparison, then I rasp the sides which gives a squarish point, the corners are then rasped off and it's then ready for my 'pencil sharpener' style sanding tool.
This tool removes wood but more important indicates the area where more needs rasping off. So it's a repeated task of rasp, sand try the nock until a good fit which reaches the full depth of the hole is achieved. You can see in the final pics how a burr has been pushed up on the wood where i've put on the horn nock and twisted it back and forth to check the fit, this shows where I need to remove more wood. The  last pic shows a pencil line marking how far the horn pushes on compared with the drill, it shows the wood is getting right up into the full extent of the hole. The final operation in this part is to lightly score some lines along the very tip of the wood to help any air and excess glue squeeze out as the horn is glued on with 10minute epoxy (which of course take half an hour to cure).
I'll show where I go from here in part 2 which hopefully I'll post later today. the posts get rather ungainly when there are lots of pics and the editing is tricky as I can't get the pics to go where I want them!

Of course not everyone has a pillar drill, and if you are using a hand held drill it may be better to use a bigger bit of horn.

pics of the 'pencil sharpener ' style tool for shaping the tip of the limb is shown left. It's drilled into a block of Oak using the same drill that is used for drilling the horn nock, a slot is sawn to allow a bit of old sand belt or wet & dry paper to be slotted into it.

Update:- (6/9/2017)
I no longer user the "pencil sharpener" sanding tool and  just do it by eye and feel, pushing the horn on hard and twisting it back and forth shows up where the wood needs removing. If the horn will rock back and forth or side to side it needs more wood removed until it pushes home snug.


video