Patriot VFT Question

Jerry/NJ · 05-31-2004, 09:51 AM

A question for the users of this bow, what is your centershot measurement at the 1st burger button hole?

PABowhntr · 06-01-2004, 05:29 AM

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.

gibblet · 06-01-2004, 05:45 AM

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.

Len in Maryland · 06-01-2004, 06:45 AM

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.

gibblet · 06-01-2004, 08:54 AM

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.

PABowhntr · 06-01-2004, 10:48 AM

Quote:

Using a sight laser to measure your centershot is dependent on the datum relativity of your sight position

Alright Len, ya got me on this one. What the heck did you just say? I thought "datum" had something to do with my GPS unit.

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.

Jerry/NJ · 06-01-2004, 03:19 PM

Right Len, I knew that

Thanx for the info

mrfritz44 · 06-02-2004, 05:35 AM

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.

Len in Maryland · 06-02-2004, 07:01 AM

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.

mlaubner · 06-02-2004, 07:08 AM

So Len, does everyone need a "Hooter Shooter" to hold their bow at full draw to effectively use the laser center shot tool ?