adding point weight

[southernarcher]

I got me some carbons a while back and got out this morning and got them flyin good.My problem is I only had 125gr glue in points and aluminum screw in adaptors to work with.I got the arrows flying nicely,but I want to get the point weight up.I have a good bit of length to play with,so I don't think it will be that big of a problem to get the weight up and still be able to get good flight.
My question is this does anyone have a general rule of thumb for weight added up front to length removed?Like if I add 150gr up front should I start with 1/2in cut from the shaft?Or..am I going to just have to play with it till I get it right?

Thanks alot guys.

[Van/TX]

Normally an inch of length or 35 grains added to the point end reduces the effective spine for wood or aluminum by approx 5#'s.  Don't know about carbons but I would think if you added 150 grains you would have to cut off a bunch.  In the end though, like you said you'll just have to play with it.  Good luck....Van

[katman]

Carbons can be sensitive to spine changes, my latest experiment may help. Full length (32") 340 Axis with 300 total point weight and 29.5" 340 Axis with 425 total point weight both fly well. Seems the shorter the shaft gets the more change when shortening, doesn't seem to be a linear relationship you could build a chart with. Recomendation to add the desired point weight and trimm .25" at a time until it bareshafts slightly weak since feathers will increase the stiffness some. Takes some time but hey that is part of the fun.
Michael where in SC are you from? I am in Myrtle Beach. Getting cold tonight.

[Pete W]

Very often carbons are to stiff for the bow,yet fly good. This is why we read about someone being able to add a huge amount of point weight and filght improves. Lots of factors are involved but the bottom line is most carbon shooters are over spined for the bow.
  Try adding weight without cutting the shaft at first and see where it takes you. When more weight is indicating the spine is to weak then start cutting in small amounts.
 When I do this I fletch a couple shafts as far to the front of the clamp as possible and trim 1/4 to 1/2" at a time from the nock end. O.L's tuning guide works good.  www.bowmaker.net

Don't be surprised if you don't need to cut the shafts you have.

[southernarcher]

Katman,I'm in Florence.

Thanks guys.I tuned themin with ol's method,and they are flyin great.I will need more weight to hunt with later though.

Looks like I will just have to add the weight and see what I have.This is what I figured I'd  have to do,but it never hurts to ask.Thanks again.

[jeff / sc]

Some of us have to learn the hard way, I just got a dozen CX heritage 150's, cut the first one to 28", thinking with the 50 gr brass insert and 250 gr broadhead I should be in good shape.....wrong.  Still too stiff with my BW PL and Thawk, both 50# @28" and I'm drawing 27. Finally got a litter smarter and cut arrow to 30", then started working down, ending up with 29.5 still using the 50 brass insert plus 250 gr broadhead (includes 125 gr steel adapter).  Then I went back to the first one, replaced the 50 gr insert with a 100 gr insert and added a 285 gr broadhead (160 stos plus 125 steel adapter).  Total arrow weight around 700 gr, a little too heavy for everyday use, but it sure flys pretty and penatrates to the fletching in my broadhead dirt pile.  Not scientific, but consistantly deeper the all others on every shot.  Sure'nough good hog arrow.