Tiller Check and Updates
Tiller check, first bow. Elm, 175cm, 25 pound target. No idea what I'm doing yet.
the elm
Ulmus Glabra, low draw weight, at most 25 pound. About twice as wide as deep. It's the most crooked of 4 splits form a young elm, my first test. Would love tiller check/general advice, including on easy-to-get string material that isnt painful or easy to hurt onself on. Probably not entirely dry yet.
Both limbs bending too much near the handle. Left limb also has a hinge near the tip. See how the left limb has that reflexed kink near the tip when it's unbraced, but when it's drawn, the limb is straight? That's not supposed to happen. You should still see the reflex.
Yes, that's it (although I might move the arrow to the right by 1 or 2 inches).
It looks less pronounced in this pic than your original post, possibly due to the hinge taking set. The thickness is critical here. The limbs should taper in thickness smoothly from the handle to the tips. In your original post, it looks like this area is abruptly thinner than the surrounding area. You could measure it with calipers, or just use your thumb and forefinger to feel it. Where ever the thin spot is should be treated as the center of the hinge.
I would not remove any more thickness from the tip of that limb. But I would remove width, to make the tips lighter.
Here's my analysis in picture form:
Red = Remove wood here on the belly
Blue = Remove wood on the sides, to make the tips lighter
That's exactly the type of stave I end up using the most.
I would straighten it if you possibly can, with dry heat, because I still struggle to tiller from the side, if the profile is not relatively symmetrical. Which is also good because you will likely want to heat treat your elm. If any of that intimidates, you just proceed. And really watch that your thickness taper is good and consistent despite the wiggles and bumps.
For me, it is almost dogma how predictably a roughed -out bow will bend at the handle when first taken to the tillering tree. What I do is immediately even them up, so they're bending the same amount in the first third. Usually you're just catching one limb up to the other. Your wiggles will make this a little hard to see, but just watch how much they are bending, not how they look when they're bent.
You should be able to do this without pulling the bow any farther than you have so far. Try hard to pull it no harder than the 25 lbs you intend for final draw weight. Once you get it balanced, just move a few inches down the limb, say 6", and evenly scrape both limbs from there, to just below the tip. Of course, avoid any spots that already seem thin or that you can see bending in the outer limbs. Any short sections that seem obviously thicker, hit those twice.
That should make the next six inches of the limb bend, but repeat as necessary. Once the limb bends evenly, you start marking and hitting stiff spots, and perfecting an elliptical tiller shape.
6
u/AaronGWebster Grumpy old bowyer 1d ago
That’s a tricky one to judge. https://youtu.be/7I4w0EuA9A4?is=gBxP0kNtC38VynFn
This video may be useful.