Primitive Archer
Main Discussion Area => Bows => Topic started by: sieddy on April 29, 2015, 01:58:52 pm
-
Hi guys yet again I'd appreciate some input on the tiller of this Yew stave. It's 71" long and it's currently pulling 36# @ 17". There is quite a lot of twist in one limb which I've not been able to steam out so I flipped it to show both sides. Thanks in advance :D
-
Tips are stiff
-
Ta! :)
-
I took quite a bit off the tips but it's still looking a bit stiff. Also there's not much heartwood near the ends now and I don't really want to cut into the sapwood on the back. Any thoughts? ???
-
You can reduce the sapwood gradually, there is no need to religiously follow a ring as long as you avoid any abrupt changes.
I have bows where I've had to step down through about 8 rings.
Try to keep a fairly even thickness of sapwood and don't go less than 1/3 heartwood in my opinion.
Del
-
How wide are the tips? You can tiller from the sides to make them work more.
The ideal solution is to chase a new ring on the back, as this will reduce sapwood thickness all over. I do it very often with yew bows - leave it reasonably thick to start with, in order to see how the bow behaves, and once I'm happy I take the back down more.
If you're not comfortable doing that, don't worry too much about tillering the belly at the tips - you might end up with mostly sapwood there, but that's not the end of the world. Or you could knock down a few rings at the tips - say 8" from the tips down to the ends - and feather the violations back along the bow.
Yew will take pretty much anything you throw at it, so just pick the option that appeals to you most ;)
-
Cheers fellas ideally I want to leave the back alone but of course I might start reducing it. Do I want to get it bending more anywhere else?
-
It looks like how I start my bows, you've got the middle working, it's all about getting the outer half 2/3 of each limb coming round now.
A little bit of work on the outers, then get it braced.
I don't narrow the tips until it's moving a bit more and you know it isn't going sideways.
Del
-
Cheers Del much appreciated! :)
-
Be careful to get the mid limbs/tips moving properly before you brace it. They are still very stiff. Remember you are going for an elliptical tiller with this bow. You should have a little bend in the middle gradually increasing as you go along the limbs. As it is it gradually decreases!
-
Thanks Mike! :)
-
Hiya I'm a bit embarrassed to be posting next to such stunning ELB's ::) but nonetheless!
I've took quite a lot of material (including sapwood) of the outer halves. It's braced at 2" and I've drawn it to 20" where it's pulling 44#. Should I just keep scraping the tips and mids and brace it higher? Thanks :)
-
Looks to be a slight flat spot mid limb on the right in second pic (which is left in 3rd pic)
Also tip on left in second pic (right in 3rd pic) is still a bit stiff.
Other than that it's looking good, it's coming around.
-
Thanks mate that's really helpful! :)
-
More of the tip off one side and mid of t'other. It's braced 3" and I've had it back 22" where it's pulling 46#. Should I continue along the same lines? Thanks :)
-
Yeah, that's looking much better.
Yup, carry on along the same lines. You can narrow tips now and increase the brace.
Also spend plenty of time checking the back is clean and smooth and feeling/measuring for even thickness taper or thick stiff spots.
You are 90% there now
I did the hold a CD up to the screen, looks good. :)
Del
-
Thanks Del that has reassured me greatly it's holding together nicely so fingers crossed I'll be getting there soon. :D
-
I think its nearly there now I've had it back to 27" where it's pulling 46. I've had a few arrows through it also, it shoots well with little handshock and I'm pretty happy with it so far (it'll be even better when I've narrowed the tips some more!)
I imagine ive still got work to do but an reluctant to lose much draw weight. The bow is flipped in the pics. Any input would be greatly appreciated. Thanks again.
-
If you do the CD test you'll see it sits pretty much on the arc of a circle except the last 1/4 of the upper limb looks a tad stiff still.
I've tried drawing circles and ellipses on the pic, but it looks odd as you are aiming slightly down...
It certainly looks like the upper limb is stiff relative to the lower.
Maybe try it up the other way.
Getting that tip moving a whisker won't drop much draw weight and may help kill some hand shock. Maybe it needs a slightly heavier arrow. Just going up 50grains in point weight or up form 5/16 to 11/32 in shaft diameter can make a big difference to smoothness.
The circle is the best I can get even rotating the pic a tad. It seems to suggest the lower limb is a bit over bent in the middle rather than the upper being stiff.
If I fit an ellipse to the curve of the lower limb the ellipse has a longer horzontal axis to the vertical... !
Maybe reversing it would just be enough to even it up, it's surprising what a bifferece it can make... I've had a few bows where I've done it.
Hope you don't mind me messing with it.
Del
-
Thanks Del. I had planned for the upper limb in that pic to be the lower (I took pics of both limbs uppermost because of the twist in the bow)
So I will take a little off the outer part of that limb. Then a few scrapes off the fades and outer on the other ( lower in the pic you kindly edited)
Thanks again for the help I definitely owe you a big box of chocolates or summat. :D
-
Ah.
I missed that the pics are flipped... I'll have a go drawing circles on the top pic.
Yeah, you can see how much better it is up that way :)
Del
-
Cheers mate I'm pretty chuffed seeing that! :D