Trad Gang
Main Boards => PowWow => Topic started by: sawtoothscream on March 17, 2011, 03:58:00 PM
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how do i find out the draw weight? im going to mark a arrow out to 28" to use but is it 28" measuring from the back of the shelf? front? middle of grip?
thanks
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Most bowyers measure it from the where you nock on the string to the back of the shelf.
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The actual AMO Standard is ... but some manufacturers may not use this method..
AMO DRAW LENGTH STANDARD
For Manufacturers
Draw length is a specified distance, or the distance at the archer’s full draw, from
the nocking point on the string to the pivot point of the bow grip (or the theoretical
vertical projection of a tangency line to the pivot point parallel to the string)
plus 1 3/4”. Draw length from pivot point shall be designed at DLPP and shall be
called TRUE DRAW LENGTH.
EXAMPLE: 26 1/4” DLPP plus 1 3/4” is the equivalent of 28” draw.
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An easy way to measure draw length is to use a springy clothspin attached to front of your arrow draw back to anchor,let down and measure from bottom of nock slot to side of the cp that faces the back of arrow.
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When I order a bow from a custom shop I let them know how I check the draw weight. I do this so they will do it the same way because that's how I try to get what I'm after. I use the 1.75" towards the back of the bow from the pivot point. For most bows it is right at the back of the bow shelf. On my new Robertson, which has a more narrow riser, the 1.75" point is a bit further away from the back of the shelf.
I use a digital scale (Easton) to measure draw weight. I check every bow I have, no matter what the bow has written on it. Most are within a pound of what is written but I had one (Checkmate) that was 5 pounds heavier.
I wrap tape around a full length arrow so the near edge of the tape is 26" (my draw length)away from the bottom of the nock groove. I wrap the tape until it is raised about 1/4".
Then I put a piece of tape on the back of the bow's grip so that the top edge of the tape free floats in front of the bow shelf and just touches the underside of a nocked arrow shaft.
Then I hook the digital scale to the string and draw the arrow until the raised tape on the arrow contacts the tape in front of the shelf. That's my draw length and I read the scale. On bows where the 1.75" point is a bit away from the shelf I build the tape tab on the bow out a bit (usually this is less than 1/2 inch).
I also put a strip of raised tape on my draw length arrow at the 28" point so I can check the draw weight of the bow at this standard 28" draw. This tells me how much weight per inch my bow changes from 28-26".
The clothes pins or plastic clamps I've tried always fall off the arrow when I tried them instead of tape. Plus, I keep this taped arrow in my shop to use time after time.
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I use a hand held scale that hooks to the string and you just draw your arrow to the normal draw length and let down and the scale indicates the weight. You hand on to the scale. The scale can be purchased at any of the large traditional archery supplies for about $36.00. I normally mark my draw length witlh a piece of tape and draw that to the front of the bow.
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Javi has the correct AMO method but most of us just measture to the back (facing target) of the shelf. I use a cardboard card with a hole punched in it slid onto the arrow. I then hang the bow with a stout rope from my basement rafters and using a "S" hook, hang an ammo box full of lead ingots from the string. I keep adding ingots until the 28" mark or my draw length is met and then I weigh the box on an accurate scale. Very unwieldly but works.
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i was just thinking about this today. i was taught the AMO standard. nock groove to pivot point plus 1 3/4". using this method your draw remains consistant no matter which bow you shoot.
don
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I generally lightly apply a strip of masking or scotch tape to the side of the shelf in direct line with the lowest part of the grip. Draw the bow and have someone mark the arrow if measuring draw length (+ 1 3/4). If measuring draw wt, then use a scale and take the reading when bow is drawn to the marked point on the arrow.
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i measure/weigh to the backside of the shelf. to me, that's the real world method that applies to everyone clearly and easily.
clothespin at 28" on a shaft, drawn 'til the pin touches the bow back - measure the weight at that point.
use a really good scale, digitals are best. do it several times for an average.
that's the 28" weight, now slide the clothespin to your draw length and check. you may be surprised.
all bets are off unless you use a good scale - my only current scale choice is the easton digital.
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Deffinatly looking into buying the easton digital scale. Will most likly order one soon
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I measure from the string to the throat of the grip, then transfer that to the strike plate and mark.. Then with a draw arrow on the string I hook the string to my digital scale and pull down to the 26 1/4" mark.. that translates to 28" AMO..
Not all risers today measure 1 3/4" from the throat of the grip to the end of the shelf..
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Originally posted by Javi:
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Not all risers today measure 1 3/4" from the throat of the grip to the end of the shelf..
absolutely true - however, a broadhead arrow knows best where the riser ends as it can go no further, and that's far more real than some point 'tween that and the handle throat.
i don't care what the amo thinks or sez, my draw length is from the nock throat to front of the arrow shelf, as dictated by my arm length and form.
since the listed weight on every bow can be off by as much as 10%, each bow is a unique entity that must be tested to see if it meets yer personal requirements.
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Originally posted by Rob DiStefano:
Originally posted by Javi:
...
Not all risers today measure 1 3/4" from the throat of the grip to the end of the shelf..
absolutely true - however, a broadhead arrow knows best where the riser ends as it can go no further, and that's far more real than some point 'tween that and the handle throat.
i don't care what the amo thinks or sez, my draw length is from the nock throat to front of the arrow shelf, as dictated by my arm length and form.
since the listed weight on every bow can be off by as much as 10%, each bow is a unique entity that must be tested to see if it meets yer personal requirements. [/b]
That would be good if bows were rated at your draw length... but most are rated at 28" AMO :thumbsup:
If someone tells me the bow is 45 lbs at 28" I expect it to be at 28" AMO not 28" at some point determined by whatever method they might use this week.. That's the whole point of having a standard... it is the standard method used..
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Originally posted by Javi:
Originally posted by Rob DiStefano:
Originally posted by Javi:
...
Not all risers today measure 1 3/4" from the throat of the grip to the end of the shelf..
absolutely true - however, a broadhead arrow knows best where the riser ends as it can go no further, and that's far more real than some point 'tween that and the handle throat.
i don't care what the amo thinks or sez, my draw length is from the nock throat to front of the arrow shelf, as dictated by my arm length and form.
since the listed weight on every bow can be off by as much as 10%, each bow is a unique entity that must be tested to see if it meets yer personal requirements. [/b]
That would be good if bows were rated at your draw length... but most are rated at 28" AMO :thumbsup:
If someone tells me the bow is 45 lbs at 28" I expect it to be at 28" AMO not 28" at some point determined by whatever method they might use this week.. That's the whole point of having a standard... it is the standard method used.. [/b]
which comes back round to the concerns over trusting inked-on listed bow weights.
when someone tells me the bow is 45 lbs at 28", i check it with a digital bow scale, then i'll know for sure.
unless yer into an overdraw shelf, or play with those contraption non stick bows, the back of the shelf is the dead stop for a broadhead. don't matter if the shelf is 1" or 3" in front of the handle throat. which is why trad stick bows would best be served to have their digitally measured weight inscribed as such - from the nock throat to the front of the riser shelf - 'cause that's how we use 'em.
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Originally posted by Rob DiStefano:
Originally posted by Javi:
Originally posted by Rob DiStefano:
quote:
Originally posted by Javi:
...
Not all risers today measure 1 3/4" from the throat of the grip to the end of the shelf..
absolutely true - however, a broadhead arrow knows best where the riser ends as it can go no further, and that's far more real than some point 'tween that and the handle throat.
i don't care what the amo thinks or sez, my draw length is from the nock throat to front of the arrow shelf, as dictated by my arm length and form.
since the listed weight on every bow can be off by as much as 10%, each bow is a unique entity that must be tested to see if it meets yer personal requirements. [/b]
That would be good if bows were rated at your draw length... but most are rated at 28" AMO :thumbsup:
If someone tells me the bow is 45 lbs at 28" I expect it to be at 28" AMO not 28" at some point determined by whatever method they might use this week.. That's the whole point of having a standard... it is the standard method used.. [/b]
which comes back round to the concerns over trusting inked-on listed bow weights.
when someone tells me the bow is 45 lbs at 28", i check it with a digital bow scale, then i'll know for sure.
unless yer into an overdraw shelf, or play with those contraption non stick bows, the back of the shelf is the dead stop for a broadhead. don't matter if the shelf is 1" or 3" in front of the handle throat. which is why trad stick bows would best be served to have their digitally measured weight inscribed as such - from the nock throat to the front of the riser shelf - 'cause that's how we use 'em.
As a note... My arrows usually end up being roughly 2" longer than hitting the shelf.. :thumbsup:
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Just been outside shooting my ACS and here is what I believe.
1. My draw length is what it is for today.
2. Spine is irrelevant if your releases are dead clean and active. I am shooting 500 spine arrows at 30 inches with 125 grain points and 250 spine arrows at 30.5 inches with 180 grain glue ins and they are flying fine and going where I want them to (when I do everything right).
3. If you are not doing everything right form wise then draw length, draw weight and arrow spine are irrelevant.
DDave
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I build all my bows measuring draw weight and length from the throat of the nock to the front of the riser. It may be "wrong", but Im consistently wrong that way!
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Originally posted by PEARL DRUMS:
I build all my bows measuring draw weight and length from the throat of the nock to the front of the riser. It may be "wrong", but Im consistently wrong that way!
It won't be wrong if your riser is 1 3/4" from throat of grip to front of riser... :D
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So what is the AMO standard for self bows, anyway?
DDave
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Originally posted by damascusdave:
So what is the AMO standard for self bows, anyway?
DDave
http://www.texasarchery.org/Documents/AMO/AMOStandards.pdf
Don't think there is one.... :biglaugh:
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Originally posted by damascusdave:
So what is the AMO standard for self bows, anyway?
DDave
there are none, never could be any.
amo is all about setting business standards and has nothing to do with the real world. make life both easy and sensible, use the front of the arrow shelf, at the back of the bow, for all bow draw length considerations ... include non-selfbows, too.
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i was asking since i was going to try and find the actual wieght at 28" because a possible buyer of my bow wanted to know if it hit its wieght. after spending a little time shooting it with my new arrow i just made up (thanks for that vid and all the advice rob) its shooting bare shafts and fletched arrows right together at 20 yds. bows off the market.
anyways thanks for the help guys. deffinatly going to order a digital scale soon
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.....draw lenght is measured to the back of any said bow - case closed ! Just like Rob stated in his first post on this thread .... anything else wouldn't be standard . :D
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... anyhow,I recently purchased an Easton digital and have found some unusual results. I think out of 10 bows tested only 2 were on the marked weight from the Bowyer. Alot of the bows appear to be about 2 lbs heavy. I actually found one bow to be 5 lbs heavy. It is very interesting. Actually thought maybe the scale was off being several bows came in 2-lbs heavy."
all of this is the norm, not the exception. to have a standard for measuring precise bow weights requires a standard, calibrated tool that all bowyers use.
in the long run, a few pounds more or less isn't the end of the world, though it may be a disappointment of sorts.
then again, how was the bow weight measured? what kind of calibrated scale was used?
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I concur Rob. I measured the arrow from the valley and marked the arrow at different lengths. I used the card with a hole in it method. Seems to get things pretty close.