Compound draw weight

[Jerry Tee]

At low poundages you must be careful not to hit the back wall hard. A adult drawing a youth bow could draw 40 lbs against the back wall and the read it as peak.

[Moose]

Originally Posted by Jerry Tee

At low poundages you must be careful not to hit the back wall hard. A adult drawing a youth bow could draw 40 lbs against the back wall and the read it as peak.

However, it was my daughter and she could not pull that hard at that point to reach the draw weight given, the bow was set at 17lb at the time.

Me thinks the scales did not work correctly, one set of scales at another competition that measured my bow increased in draw weight measured on let down, the judge had to read the scales while I was at full draw as the scales kept reading 90lb once I let down (did this four times before he read at full draw)

[CPlater1]

The handheld scales we have say my 55lb compound weighs about 48lbs. I havent measured any other bows with it though.

[Jerry Tee]

To be accurate a spring balence should be tested against a range of tested dead weights. The differences between scale reading and weight should then form the basis of a calibration chart.

[ThePinkOne]

Originally Posted by Moose

My daughter had a bow weighed in at 34lb which was amazing for a bow with 20lb limbs (Hoyt Rintec), so I told the other compounds to avoid that judge.

Before somone tells me it is possible the bow reached 25lb max when fully wound up and the draw length increased and that was measured by myself on two different scales and at Aardvark.

On the other hand, my 50# bow weighed up at 34# last time.... just shows how unreliable the scales thing is, it's far more dependant on HOW you pull the bow over with those handheld scales than anything else.

I get my peak set up at Wales Archery, thay have one of those set ups with a calibrated balance and a windy handle to gradually draw the bow..... without any risk to operator and watching the weight profile- you can see the peak build, how long it sits there for then how it drops into the valley- and can lock it off at full draw if you want. Nice.

Maybe that's what they should bring in for "officially" weighing bows...?

P.

[Graham Potts]

Originally Posted by ben tarrow

This is another of the great archery myths. Most judges scales have no adjustment on them so cannot be calibrated. The only calibration that occurs is they weigh one against another, and if the difference is too great, the judge gets told to buy a new one (never actually heard of this happening in practise)

The GNAS Judge Committee check scales on an annual basis at the GNAS Judge Conference, against a 60lb dead weight (They have set up a measuring device to ensure as much accuracy as possible), and not against each other. The mark at which the 60lbs occurs is noted on the scales. It is quite likely that the scale marked does not necessarily correspond to where the 60lb is, (neither of mine are) and it is also likely that the scale is not calibrated on alb for lb basis - our key is to know whether a bow is over or within the weight as stipulated by both FITA and GNAS, and the mark on the scale form the testing enables us to do this.

Trust this might clear up the scale check piece as best I can.

[Ceri Jones]

Shot my compound for the 1st time in ages tonight, when i stopped using it 3/4months ago it was set on 58lb, checked it on the bow scales tonight and read 61lb, these are the same scales that the 1st reading was taken from and i know the bow hasnt been tamperd with, so does this mean that the spring in the scales has stretched?

[stever]

There are moves afoot to use "DIGITAL" scales alla Eastons, I am led to believe that trials are underway. I do not know how true this is but I will ask at the Judges Conferance in February. Will try to keep everyone informed.

[Astinus]

Of course those are ridiculously more expensive...

[Kae]

Originally Posted by Astinus

Of course those are ridiculously more expensive...

Unfortunately accurate equipment isn't cheap! I've just seen the invoice for the new cryogenic centrifuge (which pulls 40G's!) for the lab I play in, very scary prices!

I'd rather something cost more (£30 for a good, reasonably priced digital bow scales) and be accurate, than these horrible spring balances.

Kae.