Primitive Archer
Main Discussion Area => Bows => Topic started by: Badger on September 19, 2016, 11:43:39 am
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No Set Tillering
No set tillering is a simple way of monitoring the condition of your bow that does not rely on a sense of feel. Instead we use our scales. Whenever a bow starts to take on set or takes on permanent deformation in compression we will have a corresponding drop in draw weight. Your scales will pick up on this before it becomes visually apparent. When we are bringing our unfinished bow down to its target draw weight we want 100% of its reduction in weight to come from wood removal and 0 % of its weight reduction to come from breaking in the bow which is just another word for set. No set tillering can be used on the long string as well as the braced bow.
This is how it is done. ( long string method) We get the bow bending as evenly as possible with only a small amount of tip movement. We install the long string lets say it hangs down about 6. Assuming the bow is bending evenly we pull the bow to about 25# and carefully note where on the yardstick it was when we hit the 25#. Lets say we hit 25# at 14. We move down one inch at a time drawing it further each time as we inch toward our target draw weight (50#). As we move down we also are looking for spots on the limb that need adjusting.
Each time we advance an inch on the long string and exercise it there we go back to our benchmark at 14 to see if it has changed. If it has dropped that means the bow is taking set and we need to take action. Lots of reasons a bow might be taking set. Wood is high in moisture, not enough limb bending, bending too much in one place, design is too narrow for the weight you are asking of it. The obvious remedy is to figure out what the problem is. Too little mass is the most common tip off for an under designed bow.
Suppose once you get to 18 you see a few spots that need attention and you decide to scrape some wood off. Once you are done scraping the wood go back and start over resetting your benchmark weight at 14. Every time you remove wood you will need to reset your benchmark weight. If I am using a long string I usually do this until I hit my target weight at about 24 and then I brace the bow and start the same process over. If your bow is taking set and you keep going with this same procedure dont blame the procedure. The idea is that this system will tip you off as soon as set starts happening and give you an opportunity to remedy the situation.
Feel free to ask questions I may not have been real clear.
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If you are noticing a drop and then re-set your benchmark a couple of times and likely repeat, aren't you accumulating set anyway?
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If you loose weight because of wood removal you are not accumalating set. You have to reset everytime you remove wood.
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I mean that you won't really know if the drop is from set or wood removal. If you scrape a bit and the weight has dropped a pound at the benchmark it could be half set and half wood removal unless you really know your scrape to weight ratio.
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Minimal set tillering may be a better descriptive.
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There will no set until you bend the bow. ;)
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Ahhh so basically if you notice the lbs aren't stacking right or make and or limbs not bending ect. Any changes made restart to process....and whatever your new lbs are at the 14" mark is your new beginning
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Thanks a lot Steve. Now I got it. ;D
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Steve
your no set tillering has worked well for me, and I appreciate the help you have given me when putting it into practice a while back.
I would like to share a slighty different way of applying your method, that works well for me.
Instead of pulling to an inch mark and reading off a weight scale, then going back to the previous benchmark,
I have a series of weights that I hang on the string, and a tape measure mounted on the tiller tree that I can view. I start by measuring the draw length with a 25# weight. the weight only needs to be hung on the string long enough for the tape to be read. Then I repeat with the 25# plus a 2# weight for measuring a new draw length, then repeat with the first benchmark weight. I can observe differences as small as 1/16th of an inch, which equate to approx. 2 oz change in pull weight. I find it easier, as I can work directly in front of the tiller tree, rather than trying to pull from a distance and make the scale settle on a "rougher mark.
For me anyways, I can see the the beginnings of set much sooner and watch its development.
swamp thing- yes, at least the way i do it, every time wood is removed, I have to establish a new benchmark. I don't necessarily go all the way back to beginning though, a new benchmark at the draw length previously attained seems to work.
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Steve do you account for heat treating in your formula?
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Steve do you account for heat treating in your formula?
I don't but it does help make the mas formula work for sure.
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Steve
your no set tillering has worked well for me, and I appreciate the help you have given me when putting it into practice a while back.
I would like to share a slighty different way of applying your method, that works well for me.
Instead of pulling to an inch mark and reading off a weight scale, then going back to the previous benchmark,
I have a series of weights that I hang on the string, and a tape measure mounted on the tiller tree that I can view. I start by measuring the draw length with a 25# weight. the weight only needs to be hung on the string long enough for the tape to be read. Then I repeat with the 25# plus a 2# weight for measuring a new draw length, then repeat with the first benchmark weight. I can observe differences as small as 1/16th of an inch, which equate to approx. 2 oz change in pull weight. I find it easier, as I can work directly in front of the tiller tree, rather than trying to pull from a distance and make the scale settle on a "rougher mark.
For me anyways, I can see the the beginnings of set much sooner and watch its development.
swamp thing- yes, at least the way i do it, every time wood is removed, I have to establish a new benchmark. I don't necessarily go all the way back to beginning though, a new benchmark at the draw length previously attained seems to work.
I like that method, more precise.
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arachnid....Using that type of tillering bottom line to me is that a person has to slow down while tillering.Mistakes are nipped in the bud before further progress.It has worked well for me too.
Using the scale along with it weighing mass does help me to know exactly how much poundage is lost to the amount of material removed.Say 1/10th of an ounce removed reduces poundage 2#'s as an example,or 1/10th of an ounce removed gives me 1/8th inch positive tiller from even tiller.It really slows a person down tillering.Getting familiar with the type and condition of wood a person is working with.
I think Marc St Louis mentioned up to a 10% reduction in mass weight from heat treating.Most times at least with hickory here that happens side tillering.
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arachnid....Using that type of tillering bottom line to me is that a person has to slow down while tillering.Mistakes are nipped in the bud before further progress.It has worked well for me too.
Using the scale along with it weighing mass does help me to know exactly how much poundage is lost to the amount of material removed.Say 1/10th of an ounce removed reduces poundage 2#'s as an example,or 1/10th of an ounce removed gives me 1/8th inch positive tiller from even tiller.It really slows a person down tillering.Getting familiar with the type and condition of wood a person is working with.
I think Marc St Louis mentioned up to a 10% reduction in mass weight from heat treating.Most times at least with hickory here that happens side tillering.
Beadman, you are not using the scale to track mass here. You are using the scale to track draw weight loss due to wood damage. 1/8" of set will show a loss in draw weight.
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You took my statement out of context and related it to your mass weight formula badger.Removing wood for a lesser draw weight is'nt removing damaged wood.
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You took my statement out of context and related it to your mass weight formula badger.Removing wood for a lesser draw weight is'nt removing damaged wood.
I am not following you I think. We are measuring the draw weight just to see if it drops by itself without removing any wood. Of course if we remove any wood we have to recalibrate our benchmark starting point. We don't deal with damaged wood here, the idea is not to get any to deal with. Sorry if I am not following you properly.
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Going back to a lower draw length integrity wood check after pulling it longer to see if it has lost weight from a previous remembered number I've always done anyway to check on bows.Smaller increments of wood removed for me helps in reducing set along with the integrity check system I'll call it.Knowing precisely how much to remove to get the amount of poundage loss is very helpful is all I said,and using a scale is needed for that.
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Ok, I follow you now. Integrity check would be an accurate description. I will go into a little more detailed description of how I use it just for guys who might be following.
I like to have the tiller pretty well evened out when I brace a bow for the first time, usually at about 23" draw. I use just a slightly low brace 5".
Bow is at first brace, I place it on the tree and with no exercise I pull it to 20". I carefully note the weight and the position on the yard stick. Now I excersize the bow a bit until I get it to twenty one inches. Now I go back to the 20"mark and recheck it. If it still reads the same or at least very very close. I keep increasing the draw length until I hit target weight at about 23'. Almost all final adjustments getting it to target weight at 28"are made in the inner limbs. I like as little limb bending as possible but sometimes I have to use the whole limb. Monitoring any drops in weight caused by further bending lets me know when I can tiller the existing bending limb or need to move in with my tiller to use more limb. Very small drops in weight like 1 oz are enough to tip you off when you need more limb.
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Bow is at first brace........................ I keep increasing the draw length until I hit target weight at about 23'.
Steve, nice of you for passing along your methods. If I understand you correctly, you try to tiller it on the longstring, until tips come back 11" or so, before bracing for the first time?
thanks
willie
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Bow is at first brace........................ I keep increasing the draw length until I hit target weight at about 23'.
Steve, nice of you for passing along your methods. If I understand you correctly, you try to tiller it on the longstring, until tips come back 11" or so, before bracing for the first time?
thanks
willie
I find that long string or braced the weight reads almost the same at the same draw length. If I tiller a 50# bow to 23" on the long string it will still be about 50# at 23" when I brace it.
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Very nice of you to share your method, Steve! I'm eager to give it a go!
A couple of questions. Do you combine this method with mass/width tillering? In that case, how? Do you get to a certain draw length (say 22-23" or so) and then start removing wood on the sides? On that note, do you ever start out with the bow wider than you expect it will need to be so that you're certain you'll avoid set?
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I do all thjat when I rough out my stave. I do a bit of refinement durring the tillering process but for the most part I use the mass weight durring the rough stages and it will come out about right.
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Yes everyone should be appreciative of your shared process.I said always but not till I read the process[which was quite some time ago] and it has helped me make many a bow of mine the way I like em.Floor tillering is an art in itself.Thanks.