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Phoenix, AZ
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Discussion Starter · #1 ·
Has anyone found an easy way to measure string center for setting everything "On plane"? There doesn't seem to any flat spots on both sides of the riser.

Right under the grip is spot I used, but it's questionable.

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Phoenix, AZ
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Discussion Starter · #2 ·
Btw, it seems the Formula X has a deeper cut sight window. Seems to have a bigger gap between the inside of the arrow shaft and the sight window.
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Don't know if it will work, but have you ever seen one of those "center shot" tools? They come and go, usually marketed/sold by a hobbyist, and really are nothing more than a flat spot yo lay against the riser [usually the sight mount are] and with the marker [usually a little o-ring, but I've got one that's actually threaded], you first set it to touch the string, then flip it to see where the marker hits the arrow; it essentially establishes a horizontal distance [strings/arrow] from a fixed point [riser sight mount area]... I've been thinking this may also be adapted to check limbs against another point, like the stab/; perhaps from each limb to the stator from the riser to the stab then from the riser to the limbs. Hopefully the idea came across, and sparks some ideas that may actually work...
 

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Not really! Four limb guages and checking with multiple long rods that I was pretty sure were both straight was the best I got. To my eye it looks like your string is not on the centre of your longrod - looks like it runs to the left. If it looks the same with another long rod I’d tweak that personally (given that there is no pfaffing with bolts and washers anymore). I’m assuming the string is in the middle of the bottom limb guage too!

What I did find was that with Velos limbs it was much noisier and a little buzzy when alignment was out even a tiny bit. Might not show the same on different limbs or heavier arrows. Very quiet and not much vibration once aligned (and I needed to change my string setup to make it truly quiet).

When I tried to measure the string to on plane the results were obviousness not good. Leading me to conclude that the “flat“ surfaces were not flat.

FWIW your plunger looks “about the same as mine”. In my case a fraction under 7mm (6.9mm I think) measured from the baseplate of a shibuya rest to the end of the tip. That puts my 32” X10 a hair outside the string.

Not sure that helps any!

Stretch
 

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I've tried to find this info for Hoyt risers without success. Apparently it is a closely held trade secret. I came up with a simple solution that is far better than "guessing/eyeballing". It requires a small length of angle aluminum, an AN bolt with an "X" on the head, and a dial caliper. Short of having access to AN hardware you may be able to measure and mark an SAE bolt. I found my two Hoyt 25" & 27" RX risers to be 1" and my wife's Win & Win Winact VT to be 0.875". Numbers one might expect.

I use the measurement from the edge of the aluminum to the center of the bolt to set my button depth. When I have set the button depth equal to CL distance + wraparound rest thickness if used - 1/2 arrow diameter the arrows are dead on bow center plane to the extent that my eye can discern. This makes it easy to switch arrows of different diameters. If you are off-setting your arrows 1/2 arrow diameter before draw then BD = CL + WR - 1/2 arrow dia. + (brace height/arrow length x 1/2 arrow diameter). Barrel shaped shafts you are on your own.

Perhaps folks who make the measurement could post them here and the OP could summarize them in the first post.

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Caveats: the riser is not bent, the aluminum angle is not bent, the stabilizer insert is on the center line etc.
 

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Phoenix, AZ
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Discussion Starter · #6 ·
Not really! Four limb guages and checking with multiple long rods that I was pretty sure were both straight was the best I got. To my eye it looks like your string is not on the centre of your longrod - looks like it runs to the left. If it looks the same with another long rod I’d tweak that personally (given that there is no pfaffing with bolts and washers anymore). I’m assuming the string is in the middle of the bottom limb guage too!

What I did find was that with Velos limbs it was much noisier and a little buzzy when alignment was out even a tiny bit. Might not show the same on different limbs or heavier arrows. Very quiet and not much vibration once aligned (and I needed to change my string setup to make it truly quiet).

When I tried to measure the string to on plane the results were obviousness not good. Leading me to conclude that the “flat“ surfaces were not flat.

FWIW your plunger looks “about the same as mine”. In my case a fraction under 7mm (6.9mm I think) measured from the baseplate of a shibuya rest to the end of the tip. That puts my 32” X10 a hair outside the string.

Not sure that helps any!

Stretch
Plunger is not at center shot in the above photo, but slightly left. And although you can't see the bottom limb guage, it is aligned perfectly. So seeing how the stabilizer and arrow relationship have such a big difference, I wanted to verify the limb and riser alignment.

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Looking for the legendary "plane" in any riser is kind of Holy Grail search that can only get to some result you can satisfy following conditions:
1) Having proper tools to check if the riser pockets inner planes are really parallel each other
2) having an already tested long rod surely straight
3) having already tested limbs surely straight and simmetrycal to their own center
4) having an already tested risers surely straight, satisfying point 1) and getting to plane with its center bushing using 2) and 3)

Procedure requires testing of new limbs and riser swapping parts with reference ones after testing for 1)

The reason why manufacturers don't want to mention exact theoretical measure of the center of the window is because it is what it is, a theoretic measure that may never be verified in the reality, as the working plane that you will find after all needed tests is most proabably out of the center of window as in design, as of:tolerancies in 1-2-3 plus the fact that the inner and outside planes of the windows are never controlled surfaces both in terms of parallelism between themselves than perpendicularity to the pocket planes.
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Phoenix, AZ
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Discussion Starter · #8 ·
Don't know if it will work, but have you ever seen one of those "center shot" tools? They come and go, usually marketed/sold by a hobbyist, and really are nothing more than a flat spot yo lay against the riser [usually the sight mount are] and with the marker [usually a little o-ring, but I've got one that's actually threaded], you first set it to touch the string, then flip it to see where the marker hits the arrow; it essentially establishes a horizontal distance [strings/arrow] from a fixed point [riser sight mount area]... I've been thinking this may also be adapted to check limbs against another point, like the stab/; perhaps from each limb to the stator from the riser to the stab then from the riser to the limbs. Hopefully the idea came across, and sparks some ideas that may actually work...
I've got a bolt on laser sight level that's actually for compounds, but it makes a great tool for recurve. I might dig that up and see how that works.

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I should have added that once you have determined the distance from the plunger mounting face you can reposition the angle aluminum so that it sits next to the string and measure the distance making adjustments as needed. For an RX that's as good as it gets since it uses washers rather than screws. I'm not too good at taking pictures of strings and Beiter gauges but they are aligned.

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I've got a bolt on laser sight level that's actually for compounds, but it makes a great tool for recurve. I might dig that up and see how that works.

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^^ Those are what I use.

Something like this + more or less the exact process in this video for both recurve and compound

 

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To use the laser alignment tool you would still need to know the distance from the sight/plunger mounting face to the center line. You would need either the engineering drawing of the riser or as mentioned a measurement from the mounting surface to a riser feature you "believe" to be on the CL i.e. the stabilizer bushing.

I checked the Gillo documentation on this procedure and their recommendation is by eyeball to the stabilizer. It was interesting to see that they offset the stabilizer bushing on the GX and GT 1mm (.039") and that when sighting the string this offset is to be taken into account.
 

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To use the laser alignment tool you would still need to know the distance from the sight/plunger mounting face to the center line. You would need either the engineering drawing of the riser or as mentioned a measurement from the mounting surface to a riser feature you "believe" to be on the CL i.e. the stabilizer bushing.

I checked the Gillo documentation on this procedure and their recommendation is by eyeball to the stabilizer. It was interesting to see that they offset the stabilizer bushing on the GX and GT 1mm (.039") and that when sighting the string this offset is to be taken into account.
That would be nice and certainly be added value, but not strictly necessary for most risers. It's definitely a piece of useful information RE: the Gillo, but still, if the bushing is more or less aligned, the laser method would just track down the length of the stabilizer with a 1mm offset and you can set everything else based off that.

You can spend an inordinate amount of time measuring and checking the various tolerance stack-ups: Is the riser straight? Are the tiller bolts themselves on plane? Are they on center? Ditto w/ the stabilizer bushing. Is the sight mounting face parallel to the center line of the riser? etc etc etc. Or you can spend ~ a half hour a get a best effort provided the riser isn't horribly made somehow.

IMO This is mostly about getting to a closer ballpark than you can achieve with any method that relies on parallax/visual judgement. A tensioned string can be nothing else but a straight line, so that provides another immediate datum starting point for laser alignment.
 

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.......

I checked the Gillo documentation on this procedure and their recommendation is by eyeball to the stabilizer. It was interesting to see that they offset the stabilizer bushing on the GX and GT 1mm (.039") and that when sighting the string this offset is to be taken into account.
GT 25 has 1 mm offset for center bushing, but not the GX, were it is on pure center.
1 mm offset: G1 25, G1 27, GQ 25, GT 23-25-27-29-31
On center: GT 19-21, Ghost 19, GQ 23, G2 25-23, GX 25
 
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