Request for those who are starting a new bow.

[DC]

I go to the back of the handle. My handles are usually 1 1/2". Close enough for me

[Badger]

Ben, primitive is pretty much always weighed at the back of the bow but amo is 26 1/4 from the deepest part of the handle. That may have been what you meant.

[Bayou Ben]

Yeah I would guess AMO isn’t based on primitive bows.  It’s just the way I saw to do it when I started building.  My handles are normally closer to 1.75”.  So if I just measure to the back the bow my draw measurement will be 1/4” different than DC’s.

[Bayou Ben]

I got the results at the first 24" and then tillered out to 28" and shot it through the chrono and I keep getting errors.  I'm using a black arrow on this second test as that was the only one that was close to the right weight.  Do you think the color of the arrow has anything to do with these errors? 

[leonwood]

Should be easier for the sensor to "see" a black arrow, do you use it outside and with the white addons above the sensor? Make sure you shoot as straight as possible and not too close to the chrono. Whit my chrony it helps if I shoot a little low through the triangle but that might scare some people

[DC]

I think that an arrow that is spined a little light gives more errors. I seem to have less errors with a stiffer arrow. If it's bending a lot it will miss a sensor. Maybe stand back a little farther but that makes it tougher to hit the sweet spot.

[Bayou Ben]

I was working on this last night, so I was inside without the white add-ons.  I know outside in the day is better, but I was getting good consistent numbers with the 1st 24" test, which is why I'm confused.  The only thing different was the arrow. 
I'll switch it up and see if that makes a difference.  I'm wondering if the arrow was light spined now that you say that DC. 

[DC]

I rarely use the white covers. I found that they make no difference and I hit one of the wires once and exploded the thing. In a brighter location they may be handy. If they weren't necessary sometimes they wouldn't use them but the whole thing is way easier without them.

[DC]

Steve, I'm at 24"@40# on my next bow. Since my DL is 26.5" I don't want to go out to 28". If I just go to 27" what will change, divide by 27 instead of 28?

[Badger]

Steve, I'm at 24"@40# on my next bow. Since my DL is 26.5" I don't want to go out to 28". If I just go to 27" what will change, divide by 27 instead of 28?

  Yes, that would be close enough, do you want to try it using both my formula and wood bears. I think his worked out closer on the last one. Mine is based on string travel rather than draw length.

[DC]

Sure,  what is Woodbears formula?

[Bayou Ben]

I used a different arrow and was able to complete the test.  The bow is an ipe/yellowheart/bamboo R/D.  I was using a 14 strand FF string and carbon arrows. 

- 51#'s @ 24" - 436 grain arrow, 175 fps

- 56#'s @ 28"- 557 grain arrow, 173 fps

- 47#'s @ 24"- 405 grain arrow, 170 fps

The first 2 seemed pretty close is speed, but the last one was definitely slower.  I had to play around with my release to get consistent readings, so the numbers are realistically + or - 2 or 3 fps, but like I mentioned the last one was slower. 

[Bayou Ben]

And don't mind the luminated nock  .  I know it's not traditional but I had to pull out every piece of arrow making that I own to meet weight. 

[DC]

Anybody know Woodbear's formula?

[Badger]

Ben, that looks like a good test and is consistent with the tests I have done on pretty well made bows, it demonstrates the loss due to hysteresis that occurred during the last few inches of tillering. Good Job. 

  Dc,  Woodbear is 24/28     mine is 18/22  somewhere inbetween seems to work out best but I do think Woodbears is a bit closer than the one I was using.