yew takedown

[Richard B]

Picture below shows the sleeves fitted. I did away with the shouldered fit in the end and faired the ends of the billets into the sleeves as described in TBB vol 3, after doing a little test piece that suggested that this might be stronger (as suggested by you guys ). I fitted a thin sapwood wedge to one of the billets to even up the reflex between both limbs (about 1"), you can see the end of it in the picture.

Good news is that both the knots I was concerned about earlier around the sleeve area disappeared as I shaped the ends to fit the sleeve (one of them became worryingly large and messy before doing so...). You can see the shadow of one of them on the bottom left hand corner of the picture.

The not so good news is that I ended up with a sloppier fit between the steel and brass sleeve than I wanted .No play side to side but I have a little play front to back (about 5mm at the end of the limb).

[Aaron H]

Looking good

[Richard B]

Trimmed both limbs width to 1 3/8" at the fades tapering to 3/4" at the tips (to allow for adjustment of string line). The thickness tapers from 25mm at the fades to about 15mm at the tips, 71 " NTN. The tip overlays are temporary, plan to reduce length to 70" NTN with the final tip overlays.

Starting to bend. As shown below, drawing 50lbs on the long string. I think I need to narrow the tips  down now to get the limbs bending more towards the tip. That and a little bit off the lower (right hand) limb should balance them up and bring them to a low brace height.

I did have a bit of a nasty moment when the bowyars knot on one end of the string came undone. There was a great crack as the bow straightened and I thought it might have fractured for a moment.  Doesn't look like any damage done to the bow . My hand didn't do so well, caught my index finger on one of the nails, lots of blood  . Felt like a real idiot, must have done it up the wrong way or something, the knot has held up for many hundreds of arrows before.....

Need to sort myself out with a pulley system for tilering.

[Carson (CMB)]

That is looking really nice Richard. I as for the bowyers knot coming undone, I have had that happen to me several times. I cant get a good bowyers not to hold in fast flight material, and so I use B-50 for tillering strings, which is annoying due to the stretch.  I found this knot diagram while looking at yumi bow website. I havent tried it yet myself, but it looks like it might be the ticket. Kind of a double bowyers knot.

[PEARL DRUMS]

I gave up on tillering strings and bowyers knots holding. I refuse to use B50. Stretching-slipping, whats the difference? I just keep a load of various ff strings on a screw in my shop wall. One will always fit whatever stage Im at with whatever bow.

[Danzn Bar]

I'm with ya Pearl.....
DBar

[Gordon]

What Pearl says...

[Richard B]

Carson, thanks for the improved knot, seems to be working well, no more misshaps . Struggling a bit with stretch though. Wanted to get off the long string and onto a low brace asap, but found that, if the string was long enough to get onto the bow without bending it beyond 55lbs, it then stretched so that I got no brace at all. Dont seem to remember having the same difficulty with my elm longbow.

Have been gradually working it down and now managed to get a 4" brace (just), which works out at 55lbs at 23 inches of draw (not much material to remove now). - Pictures below, with target curves for a 6" brace and fully drawn at 28".

The tips are now narrowed from 20mm to about 16.5mm and had to go over to one side about 1-2mm to bring the string into line with the center of the handle.

One question. The upper (left hand limb) has about 1" reflex and the lower limb (now) has not much at all - as you can see from the previous tillering picture. If I make the upper limb more curved at brace, relative to the string (as generally advised) it will have had to bend even more from its resting position. Is this a good idea?

[Richard B]

Tricky to get the lower and upper limb to an even tiller. The ring count on the upper limb is much lower than the lower limb and this seems to make the wood less stiff.

So I have had to thin down the lower limb much more (it is about 1mm thinner than the upper limb now). Made more interesting by the back of the upper limb which undulates  both down the limb and across it, making it challenging to get an even taper and to spot the curvature on the tillered shape. I think I have an even tiller, without any weak areas/hinges .  I am now at 50lbs at 26 inches draw and getting close to a balanced tiller. At 5-6" brace the tiller is such that the distance from the belly to the string is about 0.3" more on the upper limb than it is on the lower limb - which is close to where I want it to be, and close to my target curves at brace and full draw (see below) . Still a bit of work to do to even the tiller out. I want to end up at around 55lbs at 28", so not as much room for manoevre as I would have liked.

Next I plan to replace the temporary tip overlays with horn (shortening the bow length from 71" to 70" NTN) and continue tillering to 28". Also planning to back with rawhide to protect the soft yew sapwood.  Is it a good idea to overlap the rawhide slightly under the end of the overlay to protect it against unpeeling from this end? Or would it be better to do the overlays first and then lap the rawhide over the end of them slightly?

[ajooter]

I like to stop the rawhide short and cover the end with
 A seeing thread wrap.  Liquid hide glue works great for rawhide.

[Carson (CMB)]

Better to do rawhide under the overlay, otherwise it is possible for the string loop to find its way between wood and rawhide and split the two apart. After rawhide is applied to tip, you can prepare the wood/rawhide surface at an angle so that most of your overlay material is glued to wood, and only some rawhide at the leading edge.

Glad the knot is working for you. If stretch is still an issue and you are using fast flight, then it might be that you have too much twist in the body of the string. Try making adjustments with the knot rather than shortening it by twisting.

I saw you mention a loose fit. Front to back looseness can be remedied quite simply.  It sounds a bit brash after doing fine polishing but the method Richard Dyckhoff shared with me is surprisingly effective. With the take-down sleeves joined, put the handle in a vice with the back of the bow facing upward. Take a steel punch and make two to three divits down the middle of the face of the steel sleeve, over the half which has the removable limb inserted. Hard to describe. I need to draw it up.  Best to start with a couple of light raps on the punch the first go around and the check the fit. Always check the fit while bow is removed from vice, and only use enough vice pressure as necessary to hold it. Supporting the backside of the sleeve with a chunk of wood will require less force from the vice jaws.

Looking good. Very fine craftsmanship. Tiller looks pretty good to me. 

[Aaron H]

That's a good idea Carson. You are effectively mushrooming the surrounding area where you punch your divots, which takes up the loose fit.   I will have to remember that one.

[Richard B]

Carson
Thanks, some really useful advice there.

I think what you are suggesting with the rawhide was what I was thinking of doing myself, but was a  bit worried about the possibility of a peel failure under the leading edge of the tip overlay, where it has some rawhide under. However, it seems a few people have had success with this, and it does protect the end of the rawhide as you say, so I think i will go ahead and see how I get on.

I am using B50 string,which probably accounts for my problems with stretch. Was really only a big problem at the beginning at low brace, when I had to struggle to pull the pow far enough to put the string on (being careful not to go beyond 55lbs of load) only to see the string stretch and the brace disappear . Much easier now I can brace to 5-6 inches without overloading the bow.

Good idea for dealing with the loose fit on the sleeves. I shall have a go at that.

[Richard B]

Carson,
By the way, all the blind knots I was concerned about have disappeared completely as I have been taking down the belly during tillering. Either lucky, or you are very good at selecting billets

[Richard B]

The 1" or so of reflex on the upper limb has now been lost. In order to work out where this has happened I have taken a photo of the bow unstrung and superimposed it on a photo of the unstrung bow before I started tillering. It is clear that no set has occurred in the lower limb (right hand). The faint image on the photo is the original shape and I have traced a black line over the sapwood/heartwood boundary of the upper limb to aid the comparison with the current shape. It seems clear that the set has occurred in the area of the limb where the back undulated a lot, going from a crowned cross section to one with a deep dent in the middle and then back to crowned. I have attempted to taper the thickness evenly through this area on both sides and down the middle, but it must have remained an area of relative weakness. Looking at the drawn curve shape (photo above at 26" draw) there does not appear to be any sign of a hinge in this area.

On a positive note, both the upper and lower limb are now balanced in terms of reflex (dead straight). However, I would like to keep it that way if I can over the next 2" of tillering. Very little material to remove from the belly now, so not much room for manouevre. Does anyone have any ideas other than avoiding touching the belly in the area where set seems to be developing?