Hi, apparently my bow is cut to 0.0625 (I think) Can someone tell me what this really means? Does it mean that it is cut past center or short of center? Do you think I might need to build the side plate area out? I am getting fletching contact on the outside of my shelf no matter how I orientate the feathers. Bow is 62" 53#@28 pulling 28.5 (I think) shooting carbon express heritage 250's = 400ish spine 160gr. broadheads 3rivers spine calc says I am right on.

Thank you for any help.

Don't know without knowing how wide the limbs are. Is that measurement before center, past center? Plus, that is the ORIGINAL measurement, the way the bowyer built it, and doesn't allow for anything on the sight window.

Before you start looiking to the bow, look at your form. If you are getting wear on the outside of the shelf that is typically a sign of being too stiff. My guess is you need to take everything off the sight window and start over. You MIGHT be able to get those to shoot.

Any spine calcualtor or spine chart is just a staring point.

I really don't know if it is before center or past center. Thank you, I will try your suggestion.

Measure the sight window thickness at the strike plate. Sounds like 1/8th outward of center.

If your bow is on the spine calc list, and the program is giving you that number, it means that it’s cut 1/16 before center. Then you have to add the strike plate thickness to this number. After doing this, see if the chart still says your arrows are ok. My feeling is that 400s are a little stiff.

MP

When I can't tell from just looking, I will put tape on each limb, mark the center of the limbs, run a string between the two marks, and then eyeball past the string to see where the shelf is cut. I just did it on a Savannah where the arrows keep acting stiff. Now I know that I have my bow set up about an 1/8" before center and that I need to use a weaker spine arrow. It is also a good idea to scale the bow to verify that it really does draw at the weight marked on it. Most don't. Armed with that little bit of information makes it easier to choose arrows.

How long is your arrow? I get outside shelf wear even with tuned arrows if I shoot with a high elbow. Took me a long time to break that habit. If it helps, my longbow has the same cut and my gt tradional classics are 31” with 200 grains up front. 400’s. 53# at my draw. That’s 78 gr insert and 125 bh. Good luck!

Rick Barbee's home page has a link to Stu Miller's Calculator and the instructions include this diagram.

Also, when my arrows hit the shelf it is usually a stiff spine. Sometimes I can raise the nocking point to prevent the interference.

This thread title made me think about pork chops. 1 1/2" thick, GRILLED pork chops, marinated in a sweet/hot mixture!

It's just not right that I read that at 10 pm Lou...I like the way you think ..

....oh, and I forgot...WRAPPED IN BACON!

My strike plate was a very thin piece of velcro, before I asked this ? I put another piece on to thicken it up, so I tried it with the thicker strike material, the arrows appear to be flying very nice now. I will take some measurements though. Thank you to all.

According to my measurements, MPDH is correct 1/16" before center. Does this mean that adding to my strike plate thicknes is the way it should go? Mind you, the original strike P was very thin and now it is just thin. Thanks again guys!

Pushing an arrow in the horizontally away from the Bow will weaken but that should be a starting place since the arrow needs to be outboard of the string to start it in the right rotation.

You keep saying the strike plate is very thin now its thin, that means absolutely nothing!!! As little as 1/16" of an inch or .0625 will change spine required. Bows cut less than center (before) will need a weaker spine than a bow cut too center and bows cut past center will need stiffer spine than a bow cut too center.

Bob

A thicker strike plate will increase dynamic spine.

MP

If increasing the strike plate thickness improved flight, you were too weak to begin with. Sometimes it is hard to tell without experimenting. How your arrows stick into the target is another clue. If I'm hearing contact between the arrow and bow, the first thing that I look at is if the arrow sticks into the target at an angle. If I can fix that by changing tip weight, I do that first as it is easy. Only if that doesn't work will I start examining the bow for shelf cut. I do my level best not to paper tune as it hurts my feelings to strip perfectly good fletching off of an arrow.

Will strengthen, half asleep this morning. By moving the arrow outboard of the string.

If you have already registered, please

sign in now

For new registrations

Click Here