Arrow weights and point weights

albatross

Supporter
Supporter
I am in the midst of making a set of 12 longbow wooden arrows. Currently they weigh between 408 and 351 grains. The balance points are all just in front of the ideal, meaning the front is slightly heavier that the rear section. I am hoping that using a lighter point, 100 > 70 grains, on the heavier arrows will reduce the weight and move the balance point back. How much will this adjustment affect the arrow spine? The alternative is adding weight to the rear section of the arrow. Any suggestions?
 


Del the Cat

Active member
Where is your balance point and what do you consider ideal? 10% FOC is generally considered about right, maybe less for flight, more for hunting.
I don't think the changes you suggest will appreciably effect the spine.

Obviously it's very difficult to match absolutely everything without sorting through vast numbers of shafts by weight and spine to produce sets of matched shafts. Even then there may be rogue arrows in a set that don't group.
Which factors need matching may well depend to some extent on the shooting (I'm guessing here). Longer ranges may be less tolerant of balance point, short ranges less tolerant of spine? Dunno, you'd have to be a good shot to notice the difference.

I think your proposal of matching is a good start point. It can be done by adding or subtracting weight from the points . Drilling into the head to loose weight or adding solder (or drilling a hole and inserting a small length cut from a nail) to increase it can do the job, but its probably better to match the shafts in the first place.

I s'pose you need to define your margin of error, maybe matched to with 10 grains?
If you want to adjust the balance point and weight, sanding a little off the diameter at one or other end can do it without effecting the spine appreciably.
Dunno if this rambling response is any help.
At the end of the day, actual performance is the real arbiter ...
Del
PS. Dunno if you've seen this FOC calculator, it's handy. I use it for my flight arrows.
Arrow Front of Center (FOC) Calculator
 


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albatross

Supporter
Supporter
Good morning DEl.

Thanks for the reply. Your advice makes perfect sense. I am undecided as to whether make the heavier arrows match, as close as reasonable, the lighter ones, or the other way round. Or go for the mid weight and try an adjust to that. I will have a look at the the link you provided.

Thanks again.
 


Geophys

Member
I don't know where you get your shafts, but my source guarantees the dozen to weigh within 30gn, in fact it's always been less than 10 grains variation, and pretty consistent on spine. I would try and source more consistent shafts to start with.

Before cutting to length, weigh all of the shafts, then find their balance point. On heavy ones, cut from the shorter end and from the light ones from the longer end, this will at least bring their weight a little closer together.

I rarely end up with arrows that differ by more than 5 grains.
 


albatross

Supporter
Supporter
My supplier has a good reputation for quality. I think the variation is in the fact that I make footed shafts. The weight variation is probably due to differences in the hardwood (American Walnut) footings I use.
 


Del the Cat

Active member
My supplier has a good reputation for quality. I think the variation is in the fact that I make footed shafts. The weight variation is probably due to differences in the hardwood (American Walnut) footings I use.
Ah yes footings will make a big difference... you could always make 'em a tad long and then weight match by removing differing amounts from the footed end... but then visually they'd look pants....
Oh so many variables.
Have you tried adjusting weight by using different coloured fletchings ;) 🤔 😲 😄
Del
 


albatross

Supporter
Supporter
'Have you tried adjusting weight by using different coloured fletchings'

No that never occured to me! Interesting suggestion.
 


LionOfNarnia

Supporter
Supporter
adjusting weight by using different coloured fletchings
What, the concept of colour-mass hasn't made it to archery yet?

It's well known (in quantum field geometry circles) that the darker the colour, the more mass it will accrete, especially when acceleration through a magnetic field is taken into account.

- of course, in a perfect world, all fletchings would be 'perfect' silver on one side & total matte-black on the other, then spinnies would be redundant.
 


geoffretired

Supporter
Supporter
If you watch Robin Hood, he spits on the fletchings. Different amounts for different weights; at least that's what he told me.
 


albatross

Supporter
Supporter
'Robin who'?

I have found some solutions. I changed the point weight to 70 grains from 100 grains. The balance point is near as dammit FOC 10%. I reduced the weight of the heaviest shaft to the next weight down. I put to one side the 3 lightest shafts - which I will try and match to a set of lighter arrows. I now have 9 arrows that have FOC 10% and weigh within 30 grains of each other.
 


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