Measuring Bow Weight ?

[Stick Bender]

Hi Fellas on the last bow that I made it was the first time I used a digital pull gauge on my pulley system  and it took me a little while to figure out that the weight I was getting from the bow being pulled on the single point pulley system was different from the bow being pulled with three fingers on the bow in other words on the pulley 45 lb but with finger 47 lb or so , does any body have that issue and a way to figure actual weight when using a single point on the string ?

[George Tsoukalas]

Are you measuring string to back of bow in both cases?

[DC]

Where have you got the scale? The scale should hook to the string.

[Del the cat]

You have to allow for the weight of the scale if it's hanging on the string.
Or if the bow is hanging down with the scale above it, there is the additional weight of the bow.
My big scale weighs 2#
It's hard to get much more accurate than that anyway... measurement accuracy is a topic in itself, just because it's digital doesn't mean it right.
On the tillering tree the draw length scale needs to be adjustable to allow for the depth of the bow's grip, which can easilly vary by half inch or so from one bow to the next.
It's easy to get sucked in worrying about this stuff. The wonky warbow I just made was 100# at 32", but when I double checked the postion of the draw length scale it was half inch out, the reading also depended if I was standing or kneeling when I looked at it... I was doing force draw measurements every 10#, by the time I was getting to full draw it looked like 95# at 32"...
It doesn't really matter, I'm not going to take an inch off the bow or heat treat it just so I can say it's exactly 100# today, it will shift anyhow.
The one good thing is I now know it's actually been pulled to about 33.5" and thus has a decent safety margin.
While I'm droning on... if you pull the string with 3 fingers, it will be pulling the limbs back slightly further than if you are pulling on a hook.
There is just soooo much measurement error inherent in the system. I'd say plus or minus 2# is about par for the course. 
If you are worried about the extra 2#, just E-mail them to me and I'll tack 'em onto the wonky warbow
Del

[Pappy]

I zero my scale for the weight of the scale hanging on the string. When you hang the scale on the string it will register the weight of the scale before you even pull your bow, usually not much , a few pounds depending on how much the scale weighs. 2 or 3 pounds don't make much difference to me but I want to know as close as I can before writing it on the bow.
 Pappy

[Pappy]

Posting at the same time Del.
 Pappy

[Del the cat]

Posting at the same time Del.
 Pappy

Good to see you, hope the weather's nicer over there... dull, cold and damp over here.
Del

[Pappy]

23 this morning, 60 tomorrow with sun.
 Pappy

[Stick Bender]

Thanks guys I am mesuring from the back of the bow , the scale is hooked directly below the string & I take the tare weight out before testing , I never have been that good at exsplaining things in writing I usaly send pics but cant get to the shop now , so I will try it a different way when I measure on the tree the scale is weiging from a surface area of say 1/8 in. on the string (The hook on the string )When drawing the bow say I have 3 fingers on the bow with a surface area of say 3 in. On the string with the bow actually being pulled farther drawing the bow by hand , Im not trying to get crazy accurate just trying to get honest weight  numbers when I chrony the bow I dont know if that exsplained any better ?

[Pappy]

I also use a 3 hook the size of my fingers or a leather strap the is like a tab the size of my 3 fingers. I position it where my fingers would go, they both  have an eye in them to hook the scale below. Also this gives me a better picture of how it will look when I draw it instead of the single hook in the center of the string.
 
 Pappy

[Stick Bender]

Thanks Pappy great idea that will solve the problem I will just custom make it to my fingers I just have to find some stiff leather like a old barbers strap to make one Thanks !

[BowEd]

There is a tube looking type gadget that's sold that you hook to your string as you pull it when drawing by hand to measure draw weight.Forget what they call it.Wonder if that would work?It stops right where you quit drawing showing you the poundage.I could get a pic of it up later.It's in the shed outside.On hind sight here though it will probably just draw on a single point yet like the hook on the poundage tester though instead of a wider place like with your 3 fingers.

[DC]

I use a tab thing like Pappy but mine is a bit narrower. I used the widest scrap I had, bout 1 1/2". It's about 1/8" thick.

[Badger]

   Now I am getting confused, if I hang a 3# scale from my string and it reads 3# isn't the weight of the scale actually pulling my bow 3# so I should leave the 3# on there and not zero it?

[Stick Bender]

You know Mr Badger that is a excellent point some thing I never thought about  because even if my scale is setting at zero I'm  going to guess with battery's in it and all the hooks and stuff it probably weighs 2 lb it's a rather large scale so if I'm understanding your post right your saying if I'm pulling 45 lb worth of pressure I'm actually pulling 47 lb because of the weight of the scale ?