Primitive Archer
Main Discussion Area => Bows => Topic started by: Mangeur de lard on February 29, 2012, 08:02:49 pm
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Here's my little trick to ensure I don't overstress a bow while pillar-tillering.
I put a clamp to hold the bow to the pillar-jig and I hang my scale on the bottom part of the clamp.
When the bow is clamped down, I pull down on the scale until the bottom pad of the clamp just lifts off the beam of the pillar jig and I never pull any farther than that. The scale registers the weight, which is incidentally the force that the clamp is pushing against the bow. So I'll proceed like that: clamp the bow, check weight, scrape, check weight after scraping, push down the bow a little more... pretty simple actually and no need to take it out of the form. So there it is!
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Great trick Mangeur! I'll be borrowing that one for sure. Looks like it would work great for a stringer set up also.
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I like this alot!
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I do it the same way - it is also a good alternative for floortillering - you can see when it's bending even and time to string the bow.
Greetz
Cord
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Very smart idea....I often think I'm over stressing at floor tiller. That looks like a great alternative. Thanks sharing
Jon
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That's exactly it guys, knowing how much the wood is being stressed. I like the pillar tiller method, pretty straight forward. No stringer to mess with and all. I find the only drawback is that it doesn't tell you if the string is tracking properly. so that has to be checked once in a while if the stave has twist and snakes.
Randman, if the pillars are close enough together and the nocks are accessible, I see no reason you couldn't string a bow that way. Could be useful if building a very high draw weight bow.
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good idea, good looking bow on there as well, Bub
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I tried this pillar tiller idea a week or two ago and was unable to keep the bow from turning forward or back when the clamp was applied to the handle area. I tried to put some grooves in the pillars to guide the ends into but it did not keep the bow from flipping forward with any amount of regularity. Got my knuckles rapped a few times when the clamp slips due to the bow flipping forward.
Any thoughts as to what I might be doing differently than you?
Russ
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Thanks bub, it's my trade-bow-in-the-works.
RB, do you mean the bow will flip to one side or the other of the clamp? If so, it's probably because you're tillering a reflexed/recurved bow. If you look at the first pic, the bow I'm working on has a bit of recurve in the tips. It wanted to flip in the jig. In the initial stage of tillering, the bow will be unstable because the tips are lower than the handle (point of application of force). It's just like bracing a recurve with the push -pull method. At first, you need to hold the bow firmly so it doesn't flip or turn around in your hand. But as you pull, the handle goes past the tips and it doesn't want to flip anymore. Same thing with the pillar jig. If you don't want any problems from start, make sure the string is tracking in the center of the handle. Then, if tracking is good or nearly so, the problem goes away when the bow bends a bit and the handle goes under the line of the tips.
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Nice trick, Mangler of Lard. With all this talk of pillar tillering I am going to have to take a run at it. I was working out a way of checking draw weights while pillar tillering and all I could think of was to have a scale under each tip and then total up the sum of their readings....your idea is much simpler.
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Handle lower than the tips. When you say it, it makes sense. I cant recall where my handle was in relation to the tips when I tried this before - but you have encouraged me to try it again. Thanks.
Russ
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I built some pillars two weeks ago, then when i went to try it found out ALL my clamps were to short, cut the pillars down twice and still to long :o, gotta get a longer clamp, Bub
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What kind of draw weight are you looking for so to know as to not push the bow too far? I know it will not be similar to if it were strung because of the angles involved. I use this method also but haven't tried it with a scale. Steve
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If I'm making a 50 pounder, I'll stay at 50 pounds on the scale. Of course the angles of pressure of the pillars aren't exactly the same as with a string (although I think it gives a better idea than a long tillering string). I use it only to get the bow tillered to brace height, after that a normal string is put on and I use a normal tiller tree to finish.
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If I'm making a 50 pounder, I'll stay at 50 pounds on the scale. Of course the angles of pressure of the pillars aren't exactly the same as with a string (although I think it gives a better idea than a long tillering string). I use it only to get the bow tillered to brace height, after that a normal string is put on and I use a normal tiller tree to finish.
But if you never put more than the final draw weight on the handle to get your pillar tiller check ya got nothing to worry about! I use the 75% rule when tillering a bow with long string or short string anyway. Well, at least until the very last, but by then it's usually a moot point.
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I just tried it with my limbs supported about 5" in from each tip and 50# took me right about the brace height. I mad a bench several years ago with rollers on each end and a crank in the middle with a small rope. If I rebuild it I will put my scale in line next time. I really like this method for d/r and highly reflexed bows.