Cold wet day, so I set to making up a load of new ACEs. And boy, what a surprise I got. Is this normal?
First, the ACE shafts. I've got 24 brand new ACE 670 C3 shafts (should last a year or more), in two new tubes straight from Easton, all cut (by Quicks' saw) from the same end to exactly the same length. Initial weighings, straight from the tube, were all a bit different, so I cleaned the internal ends to get rid of any saw residue, and gave the inside a blast of compressed air to flush out any dust etc. Then I weighed them again carefully. My grain scales read to 0.1 grains, but the repeatability is around 0.3grn - so I weighed every shaft five times (in random order), all balancing on exactly the same point, and averaged the readings.
The result was a big surprise. I was expecting all their weights to be be very close, maybe +/- 0.3 grains or so. But....
- the first dozen ranged from 164.3grn to 166.0grn (range of 1.8grn i.e. 1.1%!!!)
- the second dozen ranged from 164.2grn to 165.6grn (range of 1.4grn i.e. 0.9%!!!)
Remember these are not only all 670s, but are all C3s - i.e. they've been selected by Easton to be close to identical. But I'm seeing 1% variation in weight. That's a lot! Can it be that Easton's quality control on ACE shafts specifies a 1% weight range as "identical"?
Second, Easton points. I got 14 brand new 100 grain break-off points here - plus 11 old (used, but cleaned) ones. I weighed them all as per the procedure I used for the shafts.
The result was a another surprise. Again I was expecting all their weights to be be very close, maybe +/- 0.3 grains or so (and the used ones to have a wider range). But....
- the first 14 (new ones) ranged from 99.3grn to 100.2grn (range of 1.0grn i.e. 1.0%!!!)
- the second 11 (used ones) ranged from 99.2grn to 100.0grn (range of 0.9grn i.e. 0.9%!!!)
Can it be that Easton's quality control on break-off points also specifies a 1% weight range as "identical: As for the old (used) ones: interesting how they've been worn out a bit - but the variation is the same.
Perhaps I'm being too picky... But as I'm building new arrows I would like them to end up all within a weight spread of 0.5grn or so. My current competition set meets this spec (well, the best 7 do, the other three are outliers). And I wasn't as careful building them.
Perhaps my weighing method is flawed in some way and actually they're really all the same weight...
I heard that the top guys get a bucket load of arrows from their sponsors and select from them. I.e. pick the most identical 12 and use them. Maybe I'm seeing the reason they do this......
First, the ACE shafts. I've got 24 brand new ACE 670 C3 shafts (should last a year or more), in two new tubes straight from Easton, all cut (by Quicks' saw) from the same end to exactly the same length. Initial weighings, straight from the tube, were all a bit different, so I cleaned the internal ends to get rid of any saw residue, and gave the inside a blast of compressed air to flush out any dust etc. Then I weighed them again carefully. My grain scales read to 0.1 grains, but the repeatability is around 0.3grn - so I weighed every shaft five times (in random order), all balancing on exactly the same point, and averaged the readings.
The result was a big surprise. I was expecting all their weights to be be very close, maybe +/- 0.3 grains or so. But....
- the first dozen ranged from 164.3grn to 166.0grn (range of 1.8grn i.e. 1.1%!!!)
- the second dozen ranged from 164.2grn to 165.6grn (range of 1.4grn i.e. 0.9%!!!)
Remember these are not only all 670s, but are all C3s - i.e. they've been selected by Easton to be close to identical. But I'm seeing 1% variation in weight. That's a lot! Can it be that Easton's quality control on ACE shafts specifies a 1% weight range as "identical"?
Second, Easton points. I got 14 brand new 100 grain break-off points here - plus 11 old (used, but cleaned) ones. I weighed them all as per the procedure I used for the shafts.
The result was a another surprise. Again I was expecting all their weights to be be very close, maybe +/- 0.3 grains or so (and the used ones to have a wider range). But....
- the first 14 (new ones) ranged from 99.3grn to 100.2grn (range of 1.0grn i.e. 1.0%!!!)
- the second 11 (used ones) ranged from 99.2grn to 100.0grn (range of 0.9grn i.e. 0.9%!!!)
Can it be that Easton's quality control on break-off points also specifies a 1% weight range as "identical: As for the old (used) ones: interesting how they've been worn out a bit - but the variation is the same.
Perhaps I'm being too picky... But as I'm building new arrows I would like them to end up all within a weight spread of 0.5grn or so. My current competition set meets this spec (well, the best 7 do, the other three are outliers). And I wasn't as careful building them.
Perhaps my weighing method is flawed in some way and actually they're really all the same weight...
I heard that the top guys get a bucket load of arrows from their sponsors and select from them. I.e. pick the most identical 12 and use them. Maybe I'm seeing the reason they do this......