Author Topic: How Stable Are Your Bows? (Read 11727 times)

PEARL DRUMS · « **Reply #15 on:** January 20, 2016, 04:00:57 pm »

I never got into them

Just boring old flat bows or flat bows with static tips. Yaaaaawn....

Badger · « **Reply #16 on:** January 20, 2016, 04:02:34 pm »

Quote from: PEARL DRUMS on January 20, 2016, 04:00:57 pm

I never got into them Just boring old flat bows or flat bows with static tips. Yaaaaawn....

Those are the best kind!

PEARL DRUMS · « **Reply #17 on:** January 20, 2016, 04:07:10 pm »

I agree Steve! I think the #1 reason for that is my usage. I hunt, that's about it. I want stable, rigid, heavy duty, aint gonna break bows when I hunt.

Danzn Bar · « **Reply #18 on:** January 20, 2016, 06:54:57 pm »

Dragonman, Chris, Steve & Brad ...Great conversation and information!..Thanks
DBar

wizardgoat · « **Reply #19 on:** January 20, 2016, 07:14:58 pm »

Very interesting stuff, drying staves and moisture content is a constant battle for me in the PNW.
I'm a positive tiller guy, they look and feel just right to me.
A couple of my better bows are still very balanced after many many arrows, but some of my earlier symmetrical limb bows show weaker bottom limbs.
Whenever I build a bow for someone else it's always a little overbuilt, for many reasons.

DC · « **Reply #20 on:** January 20, 2016, 07:30:09 pm »

Sorta related. An awful lot of the bows posted on here look like the bottom limb is weaker. Is that a camera/picture problem rather than a weak limb.

Dances with squirrels · « **Reply #21 on:** January 20, 2016, 08:55:27 pm »

This has me wondering what their tiller profiles were like originally and whether they were symmetrical or asymmetrical. I know many folks like 1/8" to 1/4" positive tiller as a general rule, but I tiller mine to balance relative to the archer's holds with no thought toward such predetermined measurements and I have never flipped a bow due to shifting tiller. Some of my bows end up with an even or negative tiller, even when I leave the bottom limb a wee bit stronger at full draw, relative to the holds on bow and string. I can't remember the last time I had a bow end up with a 1/4" positive tiller... unless it was due to a hump or other natural obvious disparity between the limbs. Naturally, this leads me to wonder whether many bows are tillered a bit too strong in the lower limb... or I'm making mine wrong ;^)

I'm just gonna think out loud here for a minute... and then let me know if you think this is a possibility, or I'm all wet.... Lets say we tiller a bow purposely so that the bottom limb is too strong, relative to our grips on bow and string. This would make the bow want to tip in the hand, with the bottom limb coming toward us without flexing as much as the top. Could this cause us to inadvertently push into the lower limb harder to resist its stronger force against the bow hand? And if so, and enough, could this change/weaken the lower limb just a tad after much repetition, which would show as a change in braced profile, and cause us to want to flip it? ...and start the process over? In other words, could making the bottom limb stronger than the top(relative at full draw) make it more prone to tiller shift, rather than less?

When these bows shift, do they shoot any different? Better? Worse? Anybody ever just keep shooting them like that and see what happens?

steve b. · « **Reply #22 on:** January 20, 2016, 09:08:44 pm »

I have to admit that I think a lot of these tiller changes come from something that Pearl Drums brought up a years or so ago. I've been thinking about it ever since--maybe a bow is not really a bow until it has been shot 1000 times. The context was different in the thread at that time but the principle may be the same, whether we are talking about tiller, broken bows, or what distinguishes a true bowyer--the bow that looks great after a 1000 shots really determines all of this. I personally have adopted this approach as a barometer in determining success.

sleek · « **Reply #23 on:** January 20, 2016, 09:25:56 pm »

Its a bow once its shot an arrow until it breaks. Is it a bow i would trust? Too many factors.

bradsmith2010 · « **Reply #24 on:** January 20, 2016, 09:30:51 pm »

yes I think a bow will settle in after 1000 shots or so,,and has not revealed its true self until then,, I agree,,
Dances with Squirrels , I will try to answer the questions I have experience with,,
Yes I have kept shooting the bow after it shifted and it depends on the bow, and most of all the length of the bow( some bows won't shoot if you put the bottom limb up, the string is on the wrong side)
from my experience ,, the way a longer bow shoots is not as sensitive to tiller shift,, the bottom limb can be weaker and with nocking the arrow in the right place or adjusting the hold on the bow,, it will shoot fine,, good arrow flight etc,,,not a problem,,
some bows may require a slight tiller adjustment to get the arrow to fly as smooth as you like,,( some shooters don't shoot well enough to tell when the tiller shifts or not,,they may just be starting or have a poor release etc and have never seen an arrow fly correctly)
for me,,the shorter the bow,, the more critical the positive tiller seems to effect the way the bow shoots,, probably string angle etc and some things I don't understand, but I can feel it in the way the bow shoots and arrow flys,,,, not as well as a short bow with positive tiller for the way I grip and shoot a bow,,
I don't think having a bow with positive tiller causes the bow to shift tiller,, I think the way we hold the bow and grip the string will put more pressure on the bottom limb,, and the bow has to be designed to handle that,, if that is longer or wider or shorter draw ,,,
if the bow is being shot in high moisture conditions or stored as Badger explained,,,that could effect a tiller change as well,,
as far as your bows go,, a self bow may not reflect a positive tiller at brace,, but at full draw the top limb is weaker or working more than the bottom limb, and so shoots as if it has a positive tiller,,even though the braced profile does not show it,,

Badger · « **Reply #25 on:** January 21, 2016, 01:33:45 am »

I make my limbs the same length but my arrow rest is about center. I tiller so the arrow pulls straight back. This will usually give me about 1/8" positive tiller but not always. I don't mind going up or down a little with the arrow nock to tune the bow if I have to.

Pappy · « **Reply #26 on:** January 21, 2016, 04:57:32 am »

I usually tiller mine about 1/8 to 3/16 pos. If the wood is well seasoned and dry they usually don't change much if any, one thing I have seen a lot is folks braceing the bow with the step through or push pull and not pay attention, they put a lot of pressure on the lower limb if not careful. I use the push pull but a stringer is the safest bet. I do tent to over build so that may be why I hardly ever have one chance after I am finished. Brad I got the pleasure of re doing one of your bows you built for Mike Prince, it had set for a long while, he got older and weaker

and the bow probable picked up a little weight over the years, I took about 10lbs off of it and retillered. it was a fine bow to start , just to heavy for him.

Pappy

dragonman · « **Reply #27 on:** January 21, 2016, 05:36:58 am »

thanks for the input, I never did properly understand positive tiller. I tried making a few bows with a shorter bottom limb, figuring that shorter meant stiffer, but it didnt feel right, and bought up more questions than answers, that just seem to over complicate the process. Now when tillering I just put the strongest limb on the bottom when I start shooting the bow in and go from there..

I see a lot of people mentioning gripping the bow, but my understanding is that to prevent torque and pulling the string out of alignment to the left or right , which will disturb arrow flight , the idea is to not grip the bow, or grip it the absolute minimum!! This way neither limb is being forced to bend more as a result of gripping...it will only bend more or less because of limb strength or knocking point position.

Isnt extra force on the bottom limb down to leverage principles? If the knocking point is above centre then the portion of string below the nocking point is longer than that above. Therefore the string is acting like a lever on the bow tips...and as in a lever, the longer the lever the more force it exerts? Untill string angle reaches 90 degrees.

Badger, interesting you say that you make your arrow rest position central!...with a stiff handle bow , doesnt this mean you will need an extra long handle section to acheive this?

Pappy · « **Reply #28 on:** January 21, 2016, 06:04:21 am »

I make most bow with same length limbs and tiller stiffer bottom limb/1/8 to 3/16 for that reason. My arrow is something above center, I never know for sure until I shoot it, I move the arrow up and down a bit until I get the feel and arrow flight I want and then mark it and that is where my arrow sets. I usually put a shelf but never do that until I have shot the bow and am satisfied with how it feels.

Pappy

Hrothgar · « **Reply #29 on:** January 21, 2016, 06:57:29 am »

I agree that having the lower limb stronger is a good solution. Besides hand grip position another factor in changing tiller over time is that the point of contact and length of contact with the string is different when being pulled by three fingers as opposed to 1/8" metal hook on the tillering tree. This is why some bowyers will test a bow an inch or so further than the final draw length.

Primitive Archer