center shot

[bsv]

Is there a way to measure how your bow is cut to center?
Burt

[**DONOTDELETE**]

run a string from tip 2 tip so that it is running down the center of the bow. Then measure from center line to side plate.

[Fletcher]

Like Sal said.  I'll string the bow and sight it so the string is down the center and see where the side plate lays.  There are more precise ways to measure, but that will get you quite close.  You can ask the bowyer, too.

[Lee Robinson .]

String the bow up, nock an arrow...step back and line the string up down the center of the riser and then look to see where the point of the arrow is in relation to the string.

[Blackstick]

Here is the Stu Miller way.

 

[bsv]

I have a b.w. recurve I"v heard that if a bow is cut to center you need to add 15#s to spine when looking at wood shafts. Is this correct?
Burt

[Lee Robinson .]

I would never want the arrow to sit "inside" of center. I believe a slight degree of directed paradox is essential to get consistency of performance. I think cut to center is fine, and cutting slightly past center is fine too as long as the center of the arrow is not past the center of the bow. Last thing I want is for the arrow to paradox into the bow and slap the riser.

[NoCams]

I think the BW calculator says to use 1.4 times the marked bow weight to get you started. But to answer your questions, yes I have heard Widows need at least 15lbs or more spine than what the bow is marked.

[Lee Robinson .]

That would depend on the draw length.

[bsv]

My draw is 29in

[Bowwild]

Great thread.  I'm getting to where I open some of these threads that sound like something I already know. Invariably, due to the expertise and creativity of folks who inhabit this site I learn something.  

I love the illustration about how to measure centershot!

I save these kinds of things for future reference.

[Bjorn]

To me including the string in a measurement of bow center makes room for ambiguity, just draw a line across the limb face at the fade, top and bottom, and join the center points, or simply email the bowyer.

[LH Keith]

What Bjorn said. My string serving is 1/8". Measuring along (side) of the string (see illustration) would mean a 1/16" off of "true center". 3 to 5 lbs. dynamic spine change on Stu's calculator. In his instructions is a much more accurate (to me) pic of center line measurement.

[ChuckC]

What Bjorn says is the easiest,looking at it strung, with string in place, especially if you mark the limb centers on tape can help you see twist in the limbs.  

However, think about some things. .  the bow, being cut TO center, means that the shelf is cut to the centerpoint of the bow. If you place an arrow on the shelf, against this riser it will not point straight ahead when nocked. This creates some of the paradox.

You also have to factor in the diameter of the arrow, actually half of it.  This is obviously accentuated with thick arrows.  A riser cut PAST center can allow an arrow to actually point ahead, reducing paradox.  

Compound bows are all cut past center.  They are pretty darned accurate arrow slinging machines.  Being cut past doesn't of itself screw up accuracy or arrow flight, but it takes different spine to acheive what you need, depending upon how close to center or how much past center you are.

That is part of the tuning endeavor.
ChuckC

[Hermon]

Originally posted by Blackstick:
Here is the Stu Miller way.

 

OK call me slow.  But isn't this picture just for bows that are cut PAST center?  Every bow that I have the bow string runs down the center of the limbs.  If I tape a string down the center line of the bow, it would be in the same plane as the bow string.  If my bow is not cut to center and I laid a straight edge along both strings, it would/should line up with the center of the bow (you would need to allow for the thickness of both strings). For bows that are NOT cut to center wouldn't you line the straight edge up with the bow string and the side plate, and measure the distance from the straight edge to the string taped along the center line of the limbs.

[ChuckC]

Wow   are we making this more difficult than it needs to be ?
ChuckC

[hkmp5]

Hello Hermon,
You are exactly correct.  I made that diagram a long time ago for a guy who was struggling to find a good way to measure his strike plate position and his bow just happened to be cut past center.  The same method can be used for a bow cut less than center you simply measure out to the shelf.  Sometimes I do take into consideration half the serving diameter but most of the time it isn't neccessary as the bowyer mostly cut to standard dimensions any more.  I most often see +1/8, 0, -1/8, or -3/16.
In attemps to make this easier, today I released the latest revision of the DSC.  One of the new features is the ability to simply pick your bow model from a list and then enter your specific strike plate thickness....the DSC does the rest.  For factory bows it seems this will be much easier.
-Stu