I recently finished (or so I thought) this BBO that I originally glued up last summer. Made some time last few weeks to get it done and I was pretty pleased until.... problems on the lower limb. Take a look.
Here she is braced. 64" NTN 55#@29" 1.25" width tapering mid limb to about 3/8" at the tips.
(http://i33.photobucket.com/albums/d83/skendrot/BBO2/IMG_2503.jpg)
At full draw. Tiller critiques welcome... seems a bit soft on the inner third on the upper (right) limb to me.. didn't really notice till I looked at the photo.
(http://i33.photobucket.com/albums/d83/skendrot/BBO2/IMG_2504.jpg)
I'm getting some thickness variations in the limb that I can't seem to get rid of. Don't know if it is the grain of the wood or what. Used Krewson's Tillering gizmo. This spot is about mid limb on the lower limb (Left in the above photo) I don't see a hinge resulting from it... Am I missing something?
(http://i33.photobucket.com/albums/d83/skendrot/BBO2/IMG_2508.jpg)
And this is what's got me nervous. I believe these are compression frets (cryssals). They are located in the depth of the dip shown in the previous photo. Barely visible but you can feel them. Light cast across the limb highlights them in the photo.
(http://i33.photobucket.com/albums/d83/skendrot/BBO2/IMG_2510.jpg)
Is this bow doomed or is there something I can do with it? I could take some more weight off. Its a great shooting bow at the moment, but I hesitate to draw it anymore until I know how to treat these frets.
I'm all ears for advice...
From the untrained eye, you look to be hinging out of the fades on the top limb too.
I don't see it either.
Wonder if you could work thru that fret, and make it into a trilam? Or shoot it until she fails. Tiller looks good on that bottom limb.
Looks like the node is causing your stiff spot. You probably already know that.
Can't wait to see what other say.
The limb will eventually fail at that dip. And the frets indicate that the process has already begun. The only way I know to save it is to glue in a wood patch at that spot.
I agree with Gordon.
I agree with John.
Well...that's three for three. I've hit the Bowyers Edge website. Dean's got an article on using plugs to repair belly defects so I guess I'll give it a whirl.
I'd be happy with a 45 pound bow. Is 10 pounds enough to work this out by retillering, or is it a character defect in the wood that will expose itself at any draw weight?
Thanks guys
I'd recommend trying the patch that Dean has on his website. I've done it a few times, both as he describes and using a slightly different approach. The sanding drum is really about the easiest way to go. I would recommend an adhesive with gap-filling properties (i.e. epoxy) and not something like TiteBond, which requires very smooth and perfect mating surfaces.
Best of luck!
Do you think a 2" sanding drum would be sufficient? Deam uses a 3" in his article, but 2" is the largest spindle I have for my rigid sander.
I think the only problem you will have with the 2" is it will cut deeper in the belly. Just guessing
I think 2" would be OK. I have done a couple with a tighter radius that that.
Not real fond of the patch fix, always the thought in the back of my head:) I would flat sand both limbs on a beltsander checking tiller while I go, then I would glue a thin lam of osage or bamboo.
JD
You could glue on a patch of rawhide right over the frets extending into the area into which you took off too much wood and hope for the best. Jawge
Hey jawge, thats why I dont do patches :) hope usually gets you nowhere:)
JD
LOL, JD.Hope springs eternal. I know. I'll never forget this. Must have been 20 years ago. I made a bow for my brother. Must have a had a fret or 2 on it. That bow just folded up like a book at full draw on the my poor bros. I'm wicha when I get a fret on a bow it becomes a tomato stake usually. :) Jawge
The best way to fix a chrysal is to not get one in the first place Steve. Constantly scan the limbs for an uneven taper. Your eyes will tell you. Also, run your hands over the limbs to check for the taper and evenness of wood removal. Seems like your wood removal tool dug in too much right over that know. BTW knotted areas should be tillered just a little stiffer than the rest of the limb. Exact opposite of the situation you have there. Couple more things when you have to make a correction in the way the limb is bending go a bit beyond the spot. Take a small no. of passes and check tiller frequently. Live and learn ha? Do you garden? :) Jawge
I would back it with sinew putting a little extra where the hinge is starting...PR
That being said, my mistakes usually put a smile on a kids face...Paul
George, I've been trying to figure out how I got that dip in the limb as I was trying to be careful to remove wood evenly. It popped up very early in the tiller process and I used the Krewson tillering gizmo throughout. I tried like crazy to remove the wood on either side of the dip to no avail. I figured it was a wave in the grain of the wood. It didn't really reveal itself as a hinge in the limb (or maybe I just missed seeing it?)so I thought the dip might not be a problem. That's not a knot, but a node in the bamboo and I read somewhere that nodes create stiff spots and I thought maybe that was explaining why the dip didn't seem to cause a hinge. I just discovered another fret in a different bow so this is a problem that seems to be plaguing me.
I do garden... but I'd much rather buy a 2 dollar stake at walmart than spend 60 hours whittling one out of wood!!!