Primitive Archer
Main Discussion Area => Bows => Topic started by: Went tam on December 15, 2013, 04:21:36 pm
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Have I got the right idea for basic tillering?
First tiller for even curve on the limbs, then set my sights on draw length and weight.
This is my third attempt on my first board bow build for my daughter. The first two were failed due to poor wood choice and bad tillering. I was told that a board bow in oak with a 26" draw @ 30 to 35# would be a good starting bow for a 15 yr old girl.
All help welcomed as I am a woodworker way out of my element on this.
Thanks
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I'm not a board bow guy, and I was gonna let one of 'em answer this for accuracy sake, but here's what I would do. Floor tiller to get each limb bending 4 to 5 inches. Try for an even amount of bend in each for the force you put on them. Then, if you have a tiller tree, pull it on the long string on the tiller tree. Pull to 4 or 5 inches, lock it in and check the limbs against each other. If one is stronger than the other take wood off until it matches the other Look for flat spots on that limb where it's not bending much. Take wood off in that or those spots. If the limb is bending nicely just stronger, take wood off from fade to tip. Once that limb is even with the other at 4-5 inches, check the tiller with a 4-5 inch straight edge on each limb. If the gap is nice and even for a ways and then increases at a spot, mark that spot and don't remove wood there. Find where the gap decreases and that is where you will remove wood until the gap is even, or close from fade to tip (really last 4-5 inches of the limb should be flat as you want the tips a good bit stiffer). Now check this corrected limb against the other. It should be a little weaker now, so, do the same on the other limb, taking wood off the flat spots until it matches the other limb in strength and shape. Once both limbs are even and bending good at 5 inches, pull it to 6 inches and do the same thing again. Keep both limbs even in weight and the gap even with the straight edge. Make sure your long string is just long enough to string the bow, you don't want a lot of slack. Get it braced at 3-4 inches when you feel comfortable you can brace it (bending good 4-5 inches or so evenly). Now just keep creeping up in draw length an inch or 2 at a time checking the limbs against one another and their shape. Easy peasy.
Once I have it braced at 5-6 inches, I want an even shape at brace, both limbs equal strength and no flat spots or hingy spots. If I can get it right at brace it will be very close the rest of the way, meaning I should be able to take wood off the entire limb rather than just one spot. If a flat spot or hingy spot shows itself, it should be very minor work in dealing with it. Hope that's helpful.
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Very helpful! Thank you!
I'll work on it and put up some pictures for reference this week if you wouldn't mind helping me check my progress.
Matt
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Glad to. Lots of others will chime in as well. Some of this is nuance and hard to put into words in the proper sequence, without skipping something small but critical. Just go slow, post pictures and ask questions as you go forward.
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slimbob tillering is tillering weather its stave or board, I think you got him on the right path
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Thanks bubby. I agree. Glad he now has a real board bow guy checking in though!
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One word "Gizmo", great tool for newbies.
http://tradgang.com/noncgi/ultimatebb.php?ubb=get_topic;f=125;t=001047#000000
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There's some board info on my site. Jawge
http://georgeandjoni.home.comcast.net/~georgeandjoni/index.html
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The gizmo mentioned above is a great tool for board bows. I wouldn't have got my first two shooters without it.
But if you ever venture into self-bows I wouldn't rely on it too much.
Keep at it and don't get discouraged. Its a tricky skill to acquire, but very rewarding once you start getting the hang of it.
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I have made over 100 selfbows with the Gizmo, it gets me to a very well tillered first brace quickly, no hinges or uneven limbs.
If you have roller coaster or twisted limbs the gizmo will be of little use, for everything else it works just fine.
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Eric, I made one using a felt pen so I could adjust out an elyptical tiller. The very fine line is the outer more bendinglimb and it gradually gets wider as the bend decreases. I kind of feel like I am cheating when I do it.
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Gizmo, straight edge or those wacky circles some are using. As long as it gets you a well tillered limb it's all good. :)
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I can't thank you guys enough for the advice and comments. The bow is at 30# at 25" with a brace height of 7.5" which I think may be a good stopping point for me and a good starting point for my daughter.
I wanted to post a few pictures but I cant find the camera cable and the Ipad file size is too large and my ability learn new stuff is maxed at the moment, I'll wait till I find the cable to post a pic.
I was planning on backing it with silk, but am curious if that is really needed or not at that draw and weight? What are your thoughts? Also, is cutting the thumbs out of a pair of old leather work gloves to make a stringing string to "redneck"? :)
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Cant wait to see it. Nothing is ever "too redneck". My opinion, I would not back it unless you have reason to believe it might fail.
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(http://i1101.photobucket.com/albums/g429/mle3434/417_zps3c8e938a.jpg) (http://s1101.photobucket.com/user/mle3434/media/417_zps3c8e938a.jpg.html)
(http://i1101.photobucket.com/albums/g429/mle3434/418_zpse9ba052d.jpg) (http://s1101.photobucket.com/user/mle3434/media/418_zpse9ba052d.jpg.html)
(http://i1101.photobucket.com/albums/g429/mle3434/420_zps2dea574f.jpg) (http://s1101.photobucket.com/user/mle3434/media/420_zps2dea574f.jpg.html)
(http://i1101.photobucket.com/albums/g429/mle3434/421_zps9df922cd.jpg) (http://s1101.photobucket.com/user/mle3434/media/421_zps9df922cd.jpg.html)
Found the cable.
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Looking a little precarious on that right fade. Loosen that up a bit.
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Thanks, I saw that also after I took the picture, but standing in front of it in person I didn't see it. I'll work on that tomorrow night.
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Yeah, I would agree, but it looks pretty good all in all. What does the straight edge say? Nice work so far. I wont leave one locked in like that btw. Tiller stick to about 15-16 inches then pull it by hand and get someone to snap a pic. Might be where some of your set is coming from.
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Looks pretty good, much better than what I would of turned out in that amount of time...... ;)
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All I would say is shoot it lots now before you finish it. When you tiller so both limbs are dead even on a tree chances are the lower will end up a little weak when actually shot and drawn by hand. You can measure the gap between the string and the belly at equal points along the limbs. The upper's distance from the string should be a little more once shot in.
Anyway good effort!
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Went through and looked at the slide show pics of the PA member bows WOW you guys are amazing!
Thanks again for all the help, the more I learn the more I realize I have to learn.
Snuck out behind the shop before everyone was up this morning and shot the bow about a dozen times. Now, I havent shot a bow since I was around 13 or 14 in gym class and I never was any good at it. But after one miss short of the small end of the hay bail at 15 yards the rest were in the hay!! I am going to have to pick up a couple of finger guard things for us because my old hands are not warn and tuff in the right spots and I can only imagine what it will do to a girls fingers.
I'm going to put a few coats of wipe on poly and bling it a little with some string silencers and it will be ready for christmas morning. The guys at Griswalds Archery in Galesburg Ill. (very helpfull gentlemen) hooked me up with 3 CF wood grain looking arrows for her to start out with.
I'll put a pic up when its 100% later this weekend.
Matt
cant wait to start on one for me now!
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Lookin' forward to seeing it all finished up. Way to go Dad!