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Bow Measurements How To?

896 views 5 replies 4 participants last post by  OverMyHead 
#1 ·
How do you measure brace height to set to factory specs? What do you use to measure it, and where do you measure from and to? What do you do to alter it?

Same question about tiller? With the cables in the way, it is hard to use a T square or a flat ruler to measure between the junction of the limb and riser and the string. How to best do it? And again, what do you do to ajust it if it is out of whack a bit?

I'm interested in fine-tuning my Hoyt's for equal tiller (if that is indeed what is wanted) and optimum brace height...I have the feeling it will make the bows quieter if I do, at least that is what I'm told.

Some pics and suggestions would be great!
 
#2 ·
Check General Archery Information - has drawing of bow and measurement points.

How do you measure brace height to set to factory specs?
Measuring from right angle of the string to the deepest part of the grip.

What do you do to alter it?
Properly adjusting string, control and buss cable for axle to axle should have brace height fall in. Twisting control and buss cables equally will add to bh and untwisting will lessen bh.

Same question about tiller?
Again, measuring at right angle from string to where the limbs meet the riser is your tiller. Making sure limb bolts are equal in adjustment should give equal tiller. Thus, turning limbs bolts adjusts tiller. You can use a straight edge, flexible tape or good string for measuring.

Will equal tiller and optimum brace height make the bows quieter?
Having bow to factory specs is a good starting point. Most bows are fairly quiet until you start adding things to them. (1) Sights are notable for vibrating and of course this makes noise. Check sight thoroughly and add dampening devices if possible. Limb Saver makes a damper for sight frames and the stick ons for limbs can be applied to fixed sight housing. (2) Add silencers to the string, cat whiskers are hard to beat. String leeches seem to wear out quickly, get damaged or get tossed out. I have nothing on my Hoyt hunting bow and it is reasonably quiet. (3) Arrows of good weight (6 grs per pound of draw weight) do a good job of suppressing noise. (4) If using a bow quiver, mount solidly and tighten securely. My 2 cents. Hope this helps.
 
#3 ·
I'm interested in fine-tuning my Hoyt's for equal tiller (if that is indeed what is wanted) and optimum brace height...I have the feeling it will make the bows quieter if I do, at least that is what I'm told.
While this is a recurve form it works the same.

http://www.texasarchery.org/Documents/BowMeasurements.htm

Good idea to record all your info.

RE optimum brace height, Most good tuners can tell if the brace height is off by the sound.

The ideal brace height would be having the arrow let go of the string as the nock is in perfect alignment with the direction of the target.

Since all arrows flex some upon release (release aid less then fingers) they will flex first one direction then the other. if you can get the arrow to be coming off the string at the exact time that it is in alignment, this will make the bow a lot quieter.

Start at the recommended brace height and then start adjusting the brace height up or down until the bow is the most quiet.

Granted rattles and other noises will be there depending on if anything is loose or if you are getting string slap, Putting silencers on only mask the sound. Don't forget that a silencer (string mounted) will also slow down the string and arrow and change the nodes of the arrow.
 
#4 ·
Measure brace height using the Field14 method



OverMyHead:

You are referring to a compound bow.

Field14 has discussed this many times, and his technique is extremely accurate.

Get yourself a bow square.

Hold the bow vertical.

Set the blade of the bow square horizontal,
as if it were lying on a table.

You are going to reverse the bow square.
The short edge is at the pivot point (deepest part of the curve).

Read the measurement to the inside face of the bow string.

Let's say the measurement is 7-15/16th inches.


Now, hold the bow square in the usual orientation
and snap it onto the bowstring.


Now, Field14 will make a permanent mark onto the riser.

I use a strip of scotch tape
and put the edge of the scotch tape at the measurement mark.


Now, you can use the bow square and snap it onto the string
and just measure to the reference edge of the scotch tape,
and your measurement of brace height will be accurate to the 1/32nd inch.
 
#5 ·
No ruler method to measure tiller

You can use an arrow to measure tiller extremely accurately.

No ruler is required.


If you want to confirm that the measurement from the upper limb to the string, matches the measurement from the bottom limb to the string....

just use an arrow.

Hold the bow so the string is vertical.

Place the tip of the arrow right at the bottom of the upper limb,
just above the limb pocket and put your thumb nail
right at the outside edge of the string.

Lock down your thumb onto the arrow.


Flip the bow upside down.
Hold the arrow so your thumbnail is at the outside edge of the string.


If the arrow tip just touches the base of the limb,
right above the limb pocket,
you have confirmed that the tiller is the same.


Tiller is just a measurement of the amount of bending of the upper limb
and the lower limb.

The assumption is that the upper and lower limb are an exact match,
for bending.

So, if both limb bolts are maxed out,
then both limbs should bend the same amount.


If necessary,
play with the limb bolts until both the upper limb
and the lower limb are bent the same exact amount.
 
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