Patriot VFT Question
06-01-2004, 05:29 AM
#2
Boone & Crockett
Join Date: Feb 2003
Location: Lehigh County PA USA
Posts: 12,157
RE: Patriot VFT Question
Jerry,
Sorry that I cannot personally help you with this one however I can offer that on most of the Bowtech models that I have set up this year the centershot is normally between 3/4 and 7/8 of an inch from the riser to the center of the arrow. I think MrFritz44 mentioned that the centershot on his Patriot SC was a little closer to the riser but I may have been mistaken.
Sorry that I cannot personally help you with this one however I can offer that on most of the Bowtech models that I have set up this year the centershot is normally between 3/4 and 7/8 of an inch from the riser to the center of the arrow. I think MrFritz44 mentioned that the centershot on his Patriot SC was a little closer to the riser but I may have been mistaken.
06-01-2004, 05:45 AM
#3
Join Date: Apr 2004
Location:
Posts: 2,981
RE: Patriot VFT Question
to the center of the arrow it is 13/16 with my tape, which is a little mangled on the end - but that is at least close for ya. centershot was acheived with a laser so the arrows in the right place, but my tape may be off 1/16 or so.
06-01-2004, 06:45 AM
#4
Join Date: Feb 2003
Location: Baltimore Maryland USA
Posts: 1,385
RE: Patriot VFT Question
Using a sight laser to measure your centershot is dependent on the datum relativity of your sight position, torque/bend in your riser, tolerance in your limb pockets, limb tip movement/angle, arrow spine, arrow nock integrity, and a few other issues.
Use of the laser and tape measurements is, however, a good starting point.
Use of the laser and tape measurements is, however, a good starting point.
06-01-2004, 08:54 AM
#5
Join Date: Apr 2004
Location:
Posts: 2,981
RE: Patriot VFT Question
why the sight placement? i've got a 29 inch draw and shoot 70lbs, and recently went from the gt 55/75 to the 75/95 because it was real hard to get tuned with the 55/75, and, as suspected, it made the job much easier and actually laser centershot paper tunes now. + i changed my grip a bit from testing with group tuning and that helped with the paper also.
06-01-2004, 10:48 AM
#6
Boone & Crockett
Join Date: Feb 2003
Location: Lehigh County PA USA
Posts: 12,157
RE: Patriot VFT Question
Using a sight laser to measure your centershot is dependent on the datum relativity of your sight position
As for the other variables, I agree. Think about it. If the sight mounting holes are off in any plane then the laser will not necessarily give you the "centershot" of the string. However, as Len mentioned, it definitely gives a reasonably good place to start.
06-02-2004, 05:35 AM
#8
Typical Buck
Join Date: Dec 2003
Location: Mertztown, PA
Posts: 970
RE: Patriot VFT Question
A friend of mine let me use a laser centershot tool and we lined up an arrow perfectly on my Patriot. Flight was lousy. After that, I relied upon the paper to tell me what it liked. From what I understand, a perfectly spined arrow will adhere to geometric centershot, but the bow's draw and the associated limb torque changes the variables associated with determining what that spine should be.
So, unless there's an equation for calculating absolute perfect spine, then a manufacturer that makes that spine for the tip you're shooting, AND if you can use that laser tool at full draw, my guess is that centershot settings are nothing more than, as Frank said, a good starting point.
It's no secret that I like the paper since I've been able to tune my broadheads to hit the same as my field tips using this technique (Muzzys and Thunderheads)....others have different views of it.
So, unless there's an equation for calculating absolute perfect spine, then a manufacturer that makes that spine for the tip you're shooting, AND if you can use that laser tool at full draw, my guess is that centershot settings are nothing more than, as Frank said, a good starting point.
It's no secret that I like the paper since I've been able to tune my broadheads to hit the same as my field tips using this technique (Muzzys and Thunderheads)....others have different views of it.
06-02-2004, 07:01 AM
#9
Join Date: Feb 2003
Location: Baltimore Maryland USA
Posts: 1,385
RE: Patriot VFT Question
mrfritz44 has posted a more 'user friendly' explanation. 
I was regretfully in a hurry yesterday when I posted that statement. Although it relates to exactly what mrfritz44 posted, it was a little - well, you know!
The "datum relativity" is questioning whether or not that surface where the sight is mounted is machined to a datum, and whether or not the addition of limbs and strings under tension are twist the riser in the sight area causing that area to no longer be relative to the datum point.
I was regretfully in a hurry yesterday when I posted that statement. Although it relates to exactly what mrfritz44 posted, it was a little - well, you know!
The "datum relativity" is questioning whether or not that surface where the sight is mounted is machined to a datum, and whether or not the addition of limbs and strings under tension are twist the riser in the sight area causing that area to no longer be relative to the datum point.