unknown spine

[Andy Cooper]

I've been cleaning out my shop and going through my arrow making supplies. Tonight I found a box with 24 unmarked cedar shafts that are 23/64" diameter. They are either 60-65# or, more likely, 70-75#. Is there any way to tell without a machine to measure the spine? I'm kinda anal about marking stuff, but these got past me.    

[JRY309]

Not that I know of without a spine tester,unless you just make them up and do some bareshafting.Maybe find some one with a spine tester close by and see.Wish I could be more help.

[d. ward]

Andy would you happen to have an arrow you know the spine on ? if so you can kind of flex them and compare it will give you some idea within 10 pounds or so ? bd

[Andy Cooper]

tr bowdoc,

I have arrows of known spine in 60-65# and 70-75#. I was thinking of suspending several shafts of each known spine weight by the ends, hanging a weight in the middle, and measuring the amount of bend-then comparing the average of ~10 of each to the amount of bend caused on the unmarked shafts.

I'm ~90% sure the unmarked ones are 70-75#.  If they are, then I no longer have a use for them. I just don't want to sell or trade shafts I don't know the spine of...and were I buying shafts, I certainly wouldn't lay down any dead presidents for unknowns!

Thanks for y'all's replies.

[Andy Cooper]

Bjorn,

I got an email notice that you'd sent a PM...but the PM isn't in my box; however, the message was contained in the email. Your suggestion parallels what I'd decided to try. All my other cedars have the spine and weight written on each shaft, so I should be able to get very close. Thanks!