Traditional Archery Discussions on the Leatherwall


Measuring the weight of a recurve

Messages posted to thread:
Dogman 12-Jun-18
Shawn 12-Jun-18
yorktown5 12-Jun-18
Bowmania 12-Jun-18
Longcruise 12-Jun-18
2 bears 12-Jun-18
buster v davenport 12-Jun-18
buster v davenport 12-Jun-18
dean 12-Jun-18
Leathercutter 12-Jun-18
aromakr 12-Jun-18
Joe2Crow 12-Jun-18
2 bears 12-Jun-18
fdp 12-Jun-18
fdp 12-Jun-18
2 bears 12-Jun-18
Dogman 16-Jun-18
GLF 17-Jun-18
Orion 17-Jun-18
raghorn 17-Jun-18
oldgoat 17-Jun-18
fdp 17-Jun-18
Renewed Archer 17-Jun-18
Glynn 17-Jun-18
Orion 17-Jun-18
Joe2Crow 17-Jun-18
fdp 17-Jun-18
Orion 17-Jun-18
Orion 17-Jun-18
Blackstick 17-Jun-18
2 bears 17-Jun-18
Orion 17-Jun-18
2 bears 18-Jun-18
Orion 18-Jun-18
2 bears 18-Jun-18
Rick Barbee 18-Jun-18
From: Dogman
Date: 12-Jun-18




I just received a take down recurve with a large riser. It feel much lighter than it's marked. How do you measure the weight. PS the riser is much deeper back to belly than a longbow. Is there a universal way to measure. PS. the bow was marked from the company.

From: Shawn
Date: 12-Jun-18




Put it on a scale with an arrow marked in 1" increments. Pull it to the 28" mark on the back of the bow and read the scale. Shawn

From: yorktown5
Date: 12-Jun-18




Shawn's not quite correct. When all bows were wood longbows and small risers, yes. But with the coming of larger risers of different fore-aft depths, grip shapes etc. the same DL to the back (target side) of the bow often delivers different poundage results than the old way.

So we changed the method. Now, the sort of "standard" way is to measure 26 1/4" from string to the deepest part of the grip (where the web between the bow hand's thumb and forefinger fits). This allows a CONSISTENT 1 3/4" average distance added regardless of where the particular bow's back (target) side really is.

Rick R.

From: Bowmania Professional Bowhunters Society - Associate Member Compton's Traditional Bowhunters
Date: 12-Jun-18




Shawn you are correct, but if I believe that if we took a pole, Shawn would be correct.

For Dogman, I'm thinking either way would work.

Bowmania

From: Longcruise
Date: 12-Jun-18




Yup, and with a deep riser measuring 28" to the back of the bow will give you an underweight measure.

From: 2 bears
Date: 12-Jun-18




yorktown5 is correct. We got lazy and started measuring them all to the back face. Bows can vary 3" or 4" in riser depth not to mention forward and rear risers,dished and straight grips. That is the reason so many folks think there bow is mismarked. Now days it depends on the maker and the age. Bowers are either adapting or getting lazy too.>>>----> Ken

From: buster v davenport
Date: 12-Jun-18




If anyone would take the time and trouble to read the AMO Standards, they would find that Rick and Shawn are both correct. Measuring to the deepest part of the grip is the standard for the manufacturers and measuring to the back of the bow is for the general public. bvd

From: buster v davenport
Date: 12-Jun-18




If anyone would take the time and trouble to read the AMO Standards, they would find that Rick and Shawn are both correct. Measuring to the deepest part of the grip is the standard for the manufacturers and measuring to the back of the bow is for the general public. bvd

From: dean
Date: 12-Jun-18




Except with straighter grip custom mild R/D and ASL longbows, they all measure to the back of the bow, because of the varied depth of the grips.

From: Leathercutter
Date: 12-Jun-18




Call the manufacture and ask how they check the weight.

From: aromakr Professional Bowhunters Society - Qualified Member
Date: 12-Jun-18




And then HOPE that your scale measures the same as the manufacture and unless both scales are certified I will guarantee they will not be the same, so why bother.

Bob

From: Joe2Crow
Date: 12-Jun-18




Today's digital scales are pretty accurate, just weigh something of known weight on them and you'll see. So I do think it's worth the bother. I measure 26 1/4 " to the deepest part of the throat as well and think it is a more consistent way to measure them. As already stated, riser widths can vary so much that it isn't reliable to use the back of the riser. Case in point, the riser on a TT recurve is about 3". When you weigh it to the deepest part of the throat, you'll come up about 2# shy of what Brian marks them. He must measure to the back of the riser but his bows consequently feel lighter than marked. It makes more sense to measure to the throat because that is where you are actually pulling against to determine draw length. Interestingly, every old Ben Pearson I have scaled, and it's been a lot, weighs within half a pound of what it is marked so I think they must have used the industry standard.

From: 2 bears
Date: 12-Jun-18




Yes Sir. AMO states 26 1/4 to the contact point of the riser + 1 3/4" for a 28" AMO which is 28" -1 1/4 " = 26 1/4" That is the way manufacturer's always measured. Which depending on the configuration of the bow may or may not be at the back face. Risers being so different is the reason for needing a standard. Nearly everyone now just measures to the face for convenience. Since the arrow needs to be out past the face bow shops began using the face for draw WEIGHT as well as arrow length/draw length.

Again that is why so many claim bows are off. They are off because they are not weighed at the right length. I have a number of bows 40+ years old that still weigh very close to the marked weight, when pulled to the right point.>>>----> Ken

From: fdp
Date: 12-Jun-18




Actually here is what the AMO/ASTM Manual says about draw length:

AMO CONVENTIONAL BOW WEIGHT MARKING STANDARD In accordance with the AMO Bow Weight Standard, the manufacturer has the option to mark his bow with actual draw weight at 28” (26 1/4” DLPP) draw or to use the following bow weight markings, especially on hunting models and middle, and low end bows. Example: Bows weighing 19 - 20 -21 lb. - will be marked 20 lbs.

Bows weighing 22 - 23 lbs. - will be marked 20X lbs.

Bows weighing 24 - 25- 26 lbs. - will be marked 25 lbs.

Bows weighing 27 - 28 lbs. - will be marked 25X lbs.

Bows weighing 29 - 30 - 31 lbs. - will be marked 30X lbs.

But like Bob said, if you scale isn't calibrated, it's really a mute point.

From: fdp
Date: 12-Jun-18




And here is the standard itself:

AMO BOW WEIGHT STANDARD For Conventional Bows Bow weight is the force required to draw the nocking point of the bow string a given distance from the pivot point of the bow grip (or the theoretical vertical projection of a tangency line to the pivot point parallel to the string). Draw length from pivot point shall be designated as DLPP and shall be referred to as TRUE DRAW LENGTH. For the purpose of uniform bow weight designation, bow weight is the force required to draw the bow string 26 1/4” from the pivot point. This weight will be marked on bow as being taken at 28” draw (26 1/4” plus 1 3/4” = 28”) See DRAW LENGTH STANDARD. EXAMPLE: Weight Adjustment Range: 45/55 lbs. Weight Set At: 50 lbs.; Hold 32 lbs. Draw Length Range: 29” - 30” EXPLANATION: The pivot point is a more realistic measuring point (when compared to the variations of profile of the back of bows at the handle section) for establishing bow weight since the pivot point is a constant in all bows as well as the contact point of the bow hand from which the true draw length is generated. The 26 1/4” DLPP is the approximate equivalent of the 28” draw used previously on the more massive wooden handle bows.

From: 2 bears
Date: 12-Jun-18




Thanks fdp we were typing at the same time. >>>----> Ken

From: Dogman
Date: 16-Jun-18




Thank you all for your comments. Just to let you all know the bow using AMO measurements is 45#. Measured to the back of the bow it's 40#. I think I'll go with AMO. Better ask your builder how they measure the weight.

From: GLF
Date: 17-Jun-18




Guys want to know what the weight is at their draw to the back of the bow no matter how thick the riser. It comes out close on most bows anyhow. I'll continue to the back of the riser like most older bowyers.

From: Orion Professional Bowhunters Society - Qualified Member Compton's Traditional Bowhunters
Date: 17-Jun-18




You're doing something wrong, Dogman, unless your bow is about 1/2inch deep from belly to back at the grip, highly unlikely.

If you get 45# with 26 1/4 from the string to the throat of the grip (AMO standard), you should get very close to the same thing when you measure 28 inches from the string to the back of the bow.

From: raghorn
Date: 17-Jun-18




Back of bow is the side away form the shooter. Measuring to back of bow was due to using broadheads. Target shooters could draw to the area within the window.

From: oldgoat
Date: 17-Jun-18




And then! You'll pull more weight to a given distance than your scale will because you use three fingers (normally) and that takes up more string than the little metal hook on a scale!

From: fdp
Date: 17-Jun-18




Actually Otion if it's 2.5" or so from the pivot point to the back of the bow across the shelf, the measurement posted would be pretty close.

From: Renewed Archer
Date: 17-Jun-18




I measure to the back of the bow but it could work either way. For me the issue is consistency so I know the relative differences in weights between my own bows. For both shooting and arrow selection.

Scales are the really important issue in weighing a bow. I had one analog scale that was gradually failing for a year but I didn't know it until it broke. At first it measured accurately based on weighing water, then it got to be 2#s off. I bought a new expensive scientific analog scale that's accurate to 1 in 300. For a 50# bow that's about 2-3 ounces. I check it a few times a year with 5 gallons of water, and make sure it's zeroed each time.

Even digital scales can be inaccurate. The digital part doesn't make them more accurate, it only reads what the mechanical/electrical sensors are measuring. I've gotten bows that were scaled w/digital scales that were up to 5# off from my calibrated analog scale, measured both AMO and back of bow methods. I have a friend who took a bow to 3 different archery shops and got 3 different weights, varying by up to 4#s.

The only other people's scales I trust are those who have already weighed bows and sent them to me, and I find that our measurements are the same.

From: Glynn
Date: 17-Jun-18




If you draw the bow with an arrow on it and have someone mark the arrow at the back of the bow, then pull it on the scale to the same mark, you will know what the bow's weight "on the fingers" or OTF is.

Make sure you do this multiple times and have someone observe the mark unbeknownst to the archer too. You have a tendency to overdraw when being watched.

From: Orion Professional Bowhunters Society - Qualified Member Compton's Traditional Bowhunters
Date: 17-Jun-18




fdp. If the riser was 2 1/2 inches thick back to belly at the grip, measuring to the back of the bow would produce a higher poundage, but not 5# on a fairly light weight bow.

Instead of measuring the draw weight at 28 inches -- 26 1/4 plus 1 3/4, the weight would be measured at 28 3/4 inches -- 26 1/4 plus 2 1/2 inches.

That 3/4 extra inch of draw would add maybe a pound to the draw weight.

Regardless, the OP is saying he got 5# less measuring to the back of the riser. As I said, doing something wrong somewhere.

From: Joe2Crow
Date: 17-Jun-18




Orion, actually you have that backwards. If the riser is over 1 3/4" and you measure to the back of the riser, you will get a light reading because you will not have drawn the 26 1/4" mark all the way to the throat.

From: fdp
Date: 17-Jun-18




Orion...Joe2Crw is correct. The further the distance from the pivot point to the back of the bow, the shorter the arrow length to the back of the bow.

You wolud have to draw into the sight window to get the full 26.25" of string follow.

From: Orion Professional Bowhunters Society - Qualified Member Compton's Traditional Bowhunters
Date: 17-Jun-18




OK, I see what you mean. If you measure that 2 1/2-inch thick riser at 28 inches at the back of the bow, that means the throat of the riser would be 25 1/2 inches, 3/4 inch less the standard 26 1/4 measurement.

Regardless, a 3/4 inch difference in measured draw length isn't going to yield a 5# difference in draw weight on a light to moderate weight bow. More like a pound or two at best.

From: Orion Professional Bowhunters Society - Qualified Member Compton's Traditional Bowhunters
Date: 17-Jun-18




Too, the example fdp gives of a 2 1/2 deep riser is on the unusual side. Not unheard of, but rare. It's unlikely the OP has a riser that large. Still something wrong in the measurement.

From: Blackstick Compton's Traditional Bowhunters
Date: 17-Jun-18




I'm with Glynn, as not all bows are made the same. The only time I care about what is marked on the bow is when I'm buying one off the internet.

From: 2 bears
Date: 17-Jun-18




Guys if you measure the weight at 26 1/4 to the deepest point of the riser. You have the AMO 28". That is why the standard was set. That is the way the "old" bowers measured and marked the bows since the standards were set. The difference to a flat faced longbow and a deep cut high wrist recurve or even a forward handle bow can be considerable. That is still where your hand is going to reach and the length of your arms don't change. The deeper the grip the closer the limbs will be to you with a longbow being the farthest away. That don't change your draw length but it sure will change your arrow length.The measurement is where your hand goes not the shape or thickness of your riser. Your longbow broadhead arrow will hit the face of a deep cut recurve. Most Compounds are machined way past center to allow the broadhead to be drawn into the riser.The 26 1/4 spec was to eliminate all the math and differences of opinion. It didn't because folks insist on measuring to the face like for the arrow length. The biggest reason folks think their bow is marked wrong. I check my scale with a 50# dumbbell each time I weigh a bow. Most scales are more accurate than the folks using them.Hope that helps.>>>----> Ken

From: Orion Professional Bowhunters Society - Qualified Member Compton's Traditional Bowhunters
Date: 17-Jun-18




Ken: We know how to take the AMO measurement. Just got off track a bit trying to figure how the OP got a 5# lower reading measuring to the back of the riser than the 26 1/4 AMO length to the throat of the riser. They should be close to identical as you note with your first two sentences.

From: 2 bears
Date: 18-Jun-18




I am sorry Orion,I know you are very knowledgeable but I don't understand what you are saying or what is in the two sentences or which post,you are referring to. In one of your posts I thought you explained it perfectly. I don't know where we differ. You know the 26 1/4 dim.correct? 28 -26 1/4 is 1 3/4. Any bow that is not exactly 1 3/4 to the back face from where the hand contacts the bow will not weight at the back the correct AMO weight as marked. 1" can easily be 3 to 5 pounds. Some bows may differ a couple of inches. The distance from your anchor to the web of your bow hand is what it is, the draw length. The average is 28" so that is where the weight of the bow is taken. The bow width and or depth of grip is the variable.The arrow length obviously has to be taken and given clearance from the back of the bow. I hope that makes sense. I wish I knew how to make sketches maybe it would be more clear.We are good.>>>---> Ken

From: Orion Professional Bowhunters Society - Qualified Member Compton's Traditional Bowhunters
Date: 18-Jun-18




Ken: We don't differ, except maybe in the amount of draw weight represented by one inch of draw length. On a lightweight bow like the OPs, somewhere between 40 and 45#, 1 inch of draw length will equate to about 1-2# of draw weight.

This thread got off track a bit along the way. Initially the OP asked how one measures draw weight, and he was given several responses including the 26 1/4 to throat of the grip AMO measurement and the 28 inches to the back of the bow commonly used method, which should yield very similar results because most bows have a riser depth pretty close to 1 3/4 inches.

On the 17th post, the OP says he got a 5# difference using the two methods, and that measuring to the back of the bow produced 5# less in draw weight. In fact, that's almost impossible and very unlikely if measured correctly. The back of the bow would have to be considerably less than 1 3/4 from the throat of the grip to yield a lesser draw weight.

Long story short, I was simply suggesting that the OP did something wrong in his measurement, or got the two terms mixed up.

From: 2 bears
Date: 18-Jun-18




O.K. I understand you now. I was pretty sure it was just communication/understanding and I am lacking in that regard.I keep asking until I get it right. I hope everyone does the same with me. Don't want to give the wrong info.Thanks,>>>----> Ken

From: Rick Barbee
Date: 18-Jun-18




Other than sometimes just trying to get a guesstimate of what a bow will be at my draw length, I never worry about what a bow's draw weight is at 28", or any other number other than my actual draw length.

To that end, I draw an arrow to my draw on the bow, and have someone place a mark on the arrow, that lines up with a mark on the bow.

I then draw the bow with that arrow on the scale, and line up the marks.

Voila - Draw weight at my draw length.

Rick





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