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Questions on new bow tillering (9/9) - at end of thread

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swotavator:
Sorry it took so long to post back.  I now have a near complete yew warbow.  It has been roughed out and both nocks are almost done.  Will be filing and sanding now.  But I have a few more questions:
1.  There is a pretty big knot I couldn't avoid.  It goes diagonally from the belly to the side of the bow, and has a crack in the belly.  My uncle works wood and mentioned some type of epoxy used for wood boat repair that seeps into cracks.  Do I need to do this?  Is this knot goign to blow up?  I have closeups in my photo bucket (below)

2.  I have removed enough wood so that my bow matches what I have heard are accurate measurements (74", 1.25" across the back, 1.5 deep at the middle tapering to 0.5 at the nocks)  When I try to floor tiller this beeotch, though, I can barely bend it - maybe 5" max (I am 200 lbs and pretty strong).  I haven't begun really tillering, and have never made a bow, so I have no idea if this is normal.  I am worried that if I remove more wood I will make it too weak.  I am shooting for around 100#. 
Can you take a look and tell me where to remove more wood?  I taper the back like this, from the center : 0-20" (1.25") 20-28" (1") 28-33" (.75") 33-37" (.5").  The profile tapers evenly from 1.5" to .5"/ 

3.  How are the nocks looking?  Too large maybe?  string groove deep enough?  Thanks for the help.

Here is my photobucket album
http://s565.photobucket.com/albums/ss97/swotavator/yew%20bow/

Davepim:
Hi Swotavator,
     Don't waste your time floor-tillering a longbow of this potential draw-weight; you should have had this on the tiller bar before now! You have probably already taken parts of the bow down too far, but it's really difficult to tell for sure without having the bow in my hand. you have done well to leave wood around some of the knots, but that really big one that  seems to go right through may be a killer; again without looking at it in real life I couldn't be sure. Following dimensions for a bow of this sort is all well and good but what you should really have done was follow how it was coming round on the tiller bar and gradually remove wood until the curve was even. This process is best done very slowly over the course of several days - once the bow starts to come round it will become easier to bend and if you do this slowly, allowing the stave to relax back to its former shape each time, you will minimise the set.

Dave

swotavator:
Fair enough.  Tough to know when most how to's are aimed at laminates.  So I might be looking at a lower poundage, but I still have a significant amount of wood left around the knot.  Do I need to glue/seal it somehow?  or just tiller, sand well, and finish the bow?

Davepim:
Well, I know what I could get away with if I was working high altitude Italian Yew, but I've never handled American. The problem with the big knot is that the grain within it runs at a different angle to the rest of the stave, and also the wood within it is very dense and relatively incompressible - so you are asking the sapwood to bend around an incompressible lump that, unlike the timber in the rest of the stave, will barely give - could in fact break along the crack-line (yes try industrial epoxy resin). However, I am continually surprised at what Yew can tolerate, and American Yew is a good timber so all I can do is suggest trying it. Take it very slowly on the tiller to get the initial bending, then relax it and leave it 24h then bend a bit more. I personally take about a week to properly tiller a self Yew bow. As with the tillering of a laminate bow, the initial bending should start about half way along each limb and the middle of the bow should be coming round gently when the bow starts to reach the maximum draw-length. Don't forget that the lower limb should be fractionally stiffer than the upper limb; no matter what people may say, a self Yew bow is not absolutely symmetrical.

Have fun! Dave

swotavator:
Cool, makes sense.  Do you think gorilla glue two part epoxy would be a good candidate?  that is what I used for the nocks, and it seems pretty resilient. 

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