Yew "fence post" longbow, part 4 - profiling

Now that the limbs have been spliced together at the handle, it's time to survey what lies in store and plan the bow accordingly.

Right now the overall length is 76", so will likely yield a bow around 74" nock to nock. This is good, as I'd like to tiller this as an English "warbow" of lighter weight -- maybe in the 60-70# at 30 (or 31? 32?) inches. The extra length will help here. Although it is meant to be a bend-through-the-handle bow, I'll want to stiffen up the handle section a little so that no undue tension is put on the spliced joint.

First, the back. One can see several of the flaws in the sapwood. Because of the narrowness of the resulting stave, there really isn't much room for avoiding some of these problems. The sapwood is also not very thick, so reducing it in thickness would not leave enough to make a decent selfbow, so I'll plan to back this with light colored rawhide, which will allow the appearance of a yew bow with the cream/brown contrast between the back and belly.

The twist at the end of the limbs can be seen fairly clearly now. The two photos below show the orientation of the crown at the tips compared to the center and middle part of the limbs (oriented correctly, with the crown centered).

The twist is not that great, but enough that I don't want to be wrestling with it while I'm tillering the bow. It is also worse at one end (the good end) than at the other. I'll plan to heat treat the belly some, and in the process I'll use some clamps and weights to gently coerce it to falling in line with the rest of the bow's crown.

Problems await on the other side, as the two knots I mentioned before could not be avoided. One is smaller than the other, and it may quite likely come out in the reducing of the belly thickness. The bigger one goes through to the sapwood side (but just a touch) and looks pretty solid so far. Hopefully I'll just be able to leave it along (or shoot it through with a spot of thin super glue) and get along nicely. The third image below shows the two knots in relation to each other; the smaller one is closer to the tip.

After lots of fussing, I managed to capture the center and crown of the stave. I mark it out using a line with chalk. The chalk is bluish-purple but comes off readily with water (or a little bit of sweat from one's palm). I use that as a rough but straight line, then follow up by marking over that in pencil, which does note rub off as readily. Then I marked the full width of the stave, 30mm at the center 4" section of the handle and 20mm at the tips. (Like many others, I switch between units of measure as a matter of convenience, marking out in mm when more precision is needed.)

You'll notice some dotted lines near that big knot. The dots actually follow the grain, and I'll respect that when I cut out the shape, leaving a little more wood around either side of the knot to help compensate for any weakness this section of the bow has.

When cutting out on the bandsaw, I did my best to keep the top of the crown uppermost, rotating the stave as it went through. In this way, the wood at the sides is always oriented perpendicular to the back, with the crown centered. It makes for some glaring twist, now that the excess wood has been taken away, but again, it will (hopefully!) come out when I heat treat and twist the tips into alignment. (In reality, they get twisted a little farther, as wood has memory and they will want to drift back to their previous position a bit.)

The true extent of the rot damage is now showing itself. It travels the limb a fair degree, but that will all be waste wood at the end of the day as the tips finally thin out, as can be seen in the second photo where I've marked the intended starting depth of 20mm at the tips.

Other sections are going to cause some challenges. Here's a section where at one time there may have been a limb. Now it is just an area where the grain runs in a divot and has cut into the working part of the limb. Some will be removed in initial thicknessing (see the pencil lines), and with luck the rest will as the belly is being shaped and tillered.

Similar challenges abound in the spliced handle section. The bow will be thickest here, but it is also where there's the least amount of wiggle room with the remaining wood. Pencil lines again show what will be removed, but there are still some significant sections of beveled wood remaining. 

[...time elapse...]

Finally the stave is brought closer to working depth by sawing off the waste wood outside the pencil lines. The dimensions I'm starting with are 20mm by 20mm at the tips and 30mm by 30mm at the handle section. We can't build a bow by numbers, but this is a starting place so that I can try and get the bow bending a bit in floor tillering. A quick weigh-in finds the stave at around 36 oz. -- which is about twice as much as it will eventually be if aiming from 70# @ 30", according to Steve Gardner's Mass Principle.

In working down the limbs, one can see that the small knot is close to disappearing. Right now it is a tiny hollow bit, which will likely come out altogether as the belly is reduced. On the other hand, that large knot has gotten slightly bigger -- and a whole lot more rotten, as the solid part came off with the waste! Just goes to show that one never really knows what lurks beneath.... I'm not sure how far the punky bits go, but I'll no need to plan to scrape out the bad bits and either a) fill the hole with a glue and sawdust mixture or b) make a wooden plug. In either case, since the knot is slightly visible on the sapwood, I'll have to assume that it is nasty all the way through.

Yew "fence post" longbow, part 3 - splitting and splicing

Laying out lines takes a lot of careful thinking and planning, checking and rechecking -- especially when there is so little room for error as there is here. On the other hand, bandsawing is relatively quick but requires an intense amount of focus when the stakes are high. One momentary lapse of attention, and the stave could be rendered into firewood -- and my planning for naught.

Well, the moment came and went, and here are the two much thinner staves. One can see the rotted section now in a good section of the stave for coming off in the profiling. From the long view, one can also see the slight jog I had to take to stay within the center of the stave.

Splicing would be a great deal easier if the wood was square or rectangular in cross section, in which case they could be stacked and cut in one go. Instead, I've marked out the waste areas on the sapwood and will need to cut each part carefully, keeping my saw lines totally perpendicular to a theoretical flat back (which is, of course, convex!). You can see the general steps below.

Once cut out, the two sections fit together fairly decently, though not perfectly. Any gaps can be filled with wooden shims so that I'm not depending solely on glue to fulfill any functional aspects.  Here are the sections dry fit with an offcut shim of yew in the background.

And here's the finished glued joint after cleaning up any of the squeeze out!

It all looks rather quick and easy here, but it was probably an hour in the marking and cutting, another hour or two in shimming, cursing, and finessing (not all necessarily in that order),  a half hour to glue and clamp, 24 to dry, and 10 minutes to unclamp and clean it up. Whew!

Now that the splice is complete, I can see that there is a bit of propellor twist at the very ends and a very slight amount of deflex. I'll plan to heat treat the belly to see if I can't get a bit of reflex into it while correcting some of the twist at the tips.

Yew "fence post" longbow, part 2 - laying out

After cutting off 4-inch section of rotted wood, it was still possible to see some rot penetrating into the stave. It looks, however, as if most of this will come off in the initial shaping and subsequent tillering, as it is fairly far from the sapwood. It also means that this section will have to be one of the outer tips if I am going to split and splice the stave back together -- which is a bit of a shame, since that end of the unsplit stave is slightly wider and would leave me more room for error in creating the splice at the handle.

Rotted end, before removal.

Remaining rot. How deep does it go?

Width of good end.

Width of rotted end. 

In these two images, one is able to compare the width of the two ends. The good end is almost a half inch narrower than the rotted end, which does not leave much room for error if I'm going to rip this into two sections to be spliced back together. Even though that makes me slightly uncomfortable, I'm going to do it anyway. How else will I learn something?

You can see from the photo at left what the ring count looks like. I mentioned in my last post that it was fairly low. Here I count between about 10-12 rings per inch. The wood, however, feels pretty heavy compared to other yew I've handled. It's kind of hard to tell from the photos, but the heartwood is very tan -- almost with a gray-green in some spots as opposed to the very reddish or orangeish yew I am used to working.

Since the wood has a lower ring count, and because the stave has pretty much no reflex (one part is slightly deflexed?), I'm planning to give the stave some heat treatment (probably after it is spliced and roughed out but before floor tillering), at which point I can induced a little relfex.

One complication is the fact that the stave, as it stands right now, jogs a little to one side at about 20 inches. In addition, there is a slight amount of propeller twist. It looks like I won't be able to lay this out with a straight cutting line along the back. Instead, I've decide to cut it straight until the stave starts to show the job and twist, at which point I'll change my cut so that it stays down the middle. (I could split this, but I worry about the lack of wiggle room. Even doing this on the bandsaw will only give me just the slightest amount of room for goofing up at the handle end. I figure I need to end with 1.25" at least to make this work.) You can just make out the jog and twist in the photos below.

Jog and twist.

Jog and twist.

One advantage to splitting the stave is that some of the bigger gouges in the sapwood are going to end up falling to one side or the other of the new thinner splits, and will eventually be worked off the entire limb as the front profile is brought in. You can see one such example in the circled section in the photo below. I think part of good bowerie is simply taking the time to really think through what the wood has to offer and how can can intelligently work around problems. An additional set of problems surrounds the two knots I identified in the last post. After splitting this stave, both should fall squarely within the middle of one of the limbs; the other limb will be knot free. I'll plan to make the knotty (naughty?) limb the upper one, since it should be slightly weaker and under a little less strain, anyhow.

Yew "fence post" longbow, part 1 - broadheads!

Jarrod must have gotten busy cleaning out his garage this summer, as the third stave I inherited from him was a 60" yew wood stave, complete with broadheads in it. I got it from his wife when I went to go pick up my son from a play date at their house. She came out of the front door with this thing cradled in her arms saying, "He tried to explain, but I couldn't quite follow. He said you'd understand...."

As I got the full story from him later, he and his buddy were shooting one day in his buddy's yard several years ago, testing broadheads by shooting at fence posts. His buddy went first, and Jarrod tried to match his shot -- only when they went to retrieve their arrows, it turns out that it wasn't a fence post at all but a yew wood stave his friend had propped up in the yard. After some cursing, his friend decided to give it to him; and after storing it for years, Jarrod had decided he was never going to get around to it.

So that's the way I got it: 60 inches of yew (only 40+ inches of it usable) from a quarter log of about 4-5 inches in diameter with two broadheads in it and some wood rot where the thing had been touching the ground as it stood in the yard. In addition, there was tape and what appeared to be a fairly old shipping label still attached.

Broadheads!

Broadhead coming through the other side. Split runs deeply.

Two things were for sure: Those broadheads were still sharp, and there was no going to be getting them out. If the wood would be usable at all, the section with the broadheads (and the surrounding splits) would have to be cut off. In addition, the section with rot going through would have to be trimmed some in the hope that the rest could be worked around. But on a positive note, the wood was really well seasoned at this point, having lived in a warm, dry garage for a number of years.

Original Tim Baker mailing label.

The first thing I decided to do (before removing the broadhead section) was to give it a really good look over. I started to remove the tape and labels only to discover that the address on the label was to one Tim Baker of Oakland, California. I can only assume that it was the Tim Baker of Traditional Bowyer's Bible fame. How funny that I should now be working on a piece of wood given to me by my friend who got it as a reject from his friend who, I can only assume, inherited it as a reject from Tim! Given the short length, narrow diameter (hence higher crown), and the low ring count, I could begin to see why this particular piece of yew did not seem to be anybody's favorite. However, I determined to make a bow out of it one way or another, and decided that there might just be enough wood in there to resaw it into two 40" billets and then splice them back together in order to make an English style longbow.

Once the tape was removed and the broadhead section removed (including a safe margin of wood just south of where it had split from the impact), it appeared that I could safely remove 4" of the rotted end and still end up with 40" of viable wood. You can see some of the rot damage from the end.

End rot, extending at least 6 inches.

An inspection of the log showed a couple of knots that would have to be dealt with -- a smaller one that can be seen from the heartwood but not from the sapwood side, and a larger one that appears to emerge through the sapwood. Fortunately, the quarter log was split and not sawn out from the larger piece, showing by the undulation in the side where the knots were travelling to.

Smaller knot, visible only from heartwood.

Larger knot, visible from heartwood.

Larger knot protruding through sapwood.

The sapwood is an altogether different bit of business. It is gouged in several places (probably from shipping, standing around in the yard, and banging around in trucks and garages) and it appears discolored (and possibly slightly rotten?) under any of the taped areas, presumably where moisture crept in or simply couldn't find its way out. After a lot of contemplating, even though I would like for it to be a selfbow, I decided that it would be best if it got backed with rawhide.

One of several gouges out of the back.

Rot(?) just under where the label tape was.

Osage "driftwood" short bow, part 4 - tillering

Now the long but critical part: Tillering.

For those who don't know, tillering is the art of removing wood carefully from the belly (and sometimes sides) of the bow to reduce thickness and/or mass in order to get the wood to bend in the way needed for the particular bow profile. (This bend might be circular and bend through the handle for bows with a straightline taper or it might be elliptical for longer bows, bows with limbs that have a more parallel taper in the midlimb, or bows with a stiff handle. It is also possible to create stiff or "whip-tillered" tips for different reasons.)

Rather than bore one with all of the details, here are some photos of the bow in progress, from start to close-to-finished tiller. Because this particular stave had some dips and whoop-de-doos that fooled the eye into thinking that they were hinges (weak spots), I found it helpful to take a series of photos and then to draw an ellipse or circle over them using the computer in order to see the weak and stiff spots better.

First, the bow braced with only a rough tiller followed by drawn to 40# @ 22". Note the stiff tips and slightly stiff lower limb (left in image):

The next photo is after quite some time tillering. It shows 25 inch draw and the drawing of the ellipse I mentioned. Because the limbs want to pull off center, I had to lighten the tips and narrow the handle a bit, lowering the max draw weight. At this point, I theorized it would probably come in more like 45 @ 28 after all of the sanding, rounding over edges, break in, etc. as it is close to 43 @ 26.

The overdrawing of the ellipse shows well that although it is pretty close to final tiller, the bottom limb (left in the image) is still stiff out near the tip and the upper limb has a slight weak spot (though it looks worse than it is because of the front to back whoop-de-doo in the limb):

At this point I was slightly disappointed that the mass was still as high as it was for the draw weight it appears to be coming in at. I think it has a lot to do with the fact that the rings are not particularly thick/wide and that there is more porous early wood, i.e. it is not the best osage. However, heat-treating the belly might squeeze a few more pounds out of it yet.

A couple of pictures close to final tiller:

Tips are still slightly stiff, but I didn't want to free them up too much, because at full draw (28") it would increase the angle between the string and arrow and cause finger pinch. Tillering shorter bend-through-the-handle bows is a little different than tillering longer bows.  Tim Baker's general tillering mantra from TBB (Traditional Bowyer's Bible) vol 4 is

Make inner limbs wide or long enough for virtually no set. Make midlimbs wide enough for little set. Make outer-limbs and tips narrow enough for lowest possible mass.

BUT, as Baker notes regarding short bows:

Unless designed for short draw, short bows must bend more in the inner limb, far more so than long bows. Whip-tillered shorter bows become shorter in tip-to-grip length during the draw, increasing string angle at full draw, increasing stack and reducing energy storage even further than typical for shorter bows. So mid and outer limbs should bend a little less, inner limbs a little more. (p.127)

Of course, too much bend in the middle or through the handle would shock the hand and, I imagine, cause accuracy to suffer. Bow building is certainly a matter of compromises.