Tuning Surprise

[Chumster]

Just started tuning my new to me Black Widow this evening. To my surprise the 3555 shot and grouped the best without much adjustment. I started out with 5575 both fletched and unfletched and the difference was amazing. I also worked up to the recommended brace height of 8 1/4 and only got to 7 3/4 before getting what I felt to be great results.
This is an amazing shooting bow.

[Night Wing]

A lot of bowhunters only tune their bows by adding or subtracting point weight. They set their bows brace height according to the bowyer's recommendation and that's it.


I, like you, only use the bowyer's recommended brace height as a starting point. Both of my 66" Blacktail TDs, the recommended brace height for them is 7.750"-8.000". However, my 42# bow's brace height is 7.562" and my 37# bow's brace height is 7.687".

[Killdeer]

Measuring brace in   thousandths???

I am such a piker.    
Killdeer

[Steve Kendrot]

I thought the same thing Killdeer! My Bear 54 pound 13 3/4 oz bow preferred a 7.766" over 7.765" brace? Now five out of five arrows hit the straw bale every time! From 10 yards no less...

[ksbowman]

Night Wing, You have way too much time on your hands being semi-retired!

[Raging Water]

Originally posted by Steve Kendrot:
I thought the same thing Killdeer! My Bear 54 pound 13 3/4 oz bow preferred a 7.766" over 7.765" brace? Now five out of five arrows hit the straw bale every time! From 10 yards no less...

Way too funny!  

[Hawkeye]

I use my outstretched thumb to check brace height... um... how many thousandths is that???    

[Night Wing]

Originally posted by Killdeer:
Measuring brace in   thousandths???

The numbers seem large, but not in the context of "fractions".              

7.750" = 7 12/16"
7.500" = 7 8/16"

Therefore, 7.562" = 7 9/16" and 7.687" = 7 11/16"

All my "thousandths" numbers are nothing more than a 1/2 twist downward (180 degrees) where I'm untwisting the bowstring on my two 66" recurves.

The conventional wisdom when an arrow is slightly stiff, to make the arrow weaker so it moves to the right for a right handed shooter, you add point weight. But, some of us old codgers shooting aluminum arrows know there is another way to make the arrow weaker and move the arrow to the right without adding more point weight.               We lower the brace height. This gives a longer power stroke so the arrow is still on the bowstring a hair longer when arrow release is achieved. This is how some people shooting slightly stiff aluminum arrows who want to shoot a 200 grain point weight instead of a 215 grain point weight, achieve it. I confirm the tune of my arrow by standing 7 yards away and paper tuning the arrow. If it shoots a perfect bullet hole at a small black dot I'm aiming at, I'm tuned. Just to confirm it again, I'll take a shot at a small pine cone 20 yards away and most of the time, I'll almost hit it.

My ultimate goal is to shoot a very heavy aluminum arrow out of my two low poundage bows, for maximum penetration, with good speed where arrow drop between 10-20 yards is not a factor.

What you see in my signature is a partial tune. The complete tune for both of my bows is below:

Blacktail TD Recurve: 66", 42# @ 30". BS: 12StrDyna97. BrcHt: 7.562" (7 9/16"). NP: 5/8". Shelf: 3/16" Past Center. Style: Tab/Split Finger. Arrow: 32", 2117. PW: 200 Grains. BH: STOS 160 Grain. Broadhead Adapter: 40 Grains. AW: 637 Grains. SPD: 153 fps. GPP: (15.16). FOC: 15.4%

Blacktail TD Recurve: 66", 37# @ 30". BS: 13StrDyna97. BrcHt: 7.687" (7 11/16'). NP: 5/8". Shelf: 3/16" Past Center. Style: Tab/Split Finger. Arrow: 32", 2114. PW: 180 Grains. BH: STOS 145 Grain. Broadhead Adapter: 35 Grains. AW: 550 Grains. SPD: 155 fps. GPP: (14.86). FOC: 16.2%

[Bowwild]

Night Wing,
Good to see your post on the brace height. You sure made a believer out of me and by the way, saved me from parting with a very expensive bow!

I shoot the 1-piece blacktail very regularly now along with 3 other of my recurves. The BT is as quiet or more so than the others now.

Thanks!

[Chumster]

Great information Night Wing and thanks for sharing.

[olddogrib]

Night Wing,
I always bought the "power stroke" theory until a post I made here a week or so ago (search: brace height adjustment affects on arrow spine posted 11-15) Several responders pointed out something I hadn't considered. If I understood them correctly, a lower relative brace height will cause the arrow to stay on the string a fraction longer and has a more pronounced angle relative to the side plate to begin with. From that perspective, lowering brace height would make the arrow have to flex slightly more (and therefore act relatively stiffer) to clear the riser compared to a higher brace (reduced angle, paradox induced earlier). I think I said that right, but you can check that post's responses.  Someone with a chrony and shooting machine actually tested the theory and an adjustment of approx. 1" brace change produced no difference in velocity.  Another also observed that a "cut past center" recurve riser would be less apt to show any effect than a typical long bow. I don't recall what type of bow they used.

[hvyhitter]

wow.....I adjust mine in 1/8ths......

Did I stumble into a math class?

[MCNSC]

I have a PSAX that was pretty loud I kept going up on brace height but it didnt help. Went back to my starting point and went down to a lower brace height and it got quieter. It is now what I consider to be very quiet with heavy arrows.
 I am now ashamed to say I dont know what the brace height was or is. Although I could measure it which wouldnt help it it were to break.   :rolleyes:

[Night Wing]

olddogrib ,

I'm not interested in arrow speed because I shoot very low bow poundages with very heavy arrows  compared with the rest of you and others here on TG. Essentially, I want to get the ...... maximum out of the minimum.

I'm also shooting a long 32" BOP aluminum arrow. I don't shoot carbon or wood arrows. I don't know if lowering the brace height when shooting slightly stiff carbon or wood arrows; will work the same way as lowering the brace height works on slightly stiff aluminum arrows, but in theory, it should. The majority of people who fiddle with brace height; they're looking to make their bows "quieter". They don't realize you can make a stiff arrow weaker by lowering the brace height because of the longer power stroke because the arrow does stay on the string a little longer when the arrow is released.

When I was 14 years old, 46 years ago, I was lucky to meet Fred Bear in person at an archery function. Fred was a very nice gentleman and he knew the future of bowhunting at the time with trad bows was with the children and young teenagers, like me, who were hanging on his every word. I got to talk with Fred for 2 1/2 hours and I'd picked Fred's brain with many, many questions. Fred answered every one of them and it was Fred who told me about lowering the brace height if an aluminum arrow was slightly stiff instead of adding point weight. This was before computers and chronographs. I know this works for aluminum arrows, but one has to lower the brace height in 1/2 twist turns on the bowstring. Then shoot a few arrows to see where the arrow is hitting and the process might have to be repeated and with me, it did.  

With Stu Miller's DSC program I'm dead on with a 215 grain point weight with my 42# bow, but I had arrow drop after 17 yards. I found with a 200 grain point weight, there was very little arrow drop out to 20 yards. But, the arrow was hitting to the left because the arrow was now slightly stiff. By lowering the brace height from 7 3/4" (7 12/16") to 7 9/16", the arrow was hitting where I was looking at 20 yards.

With my 37# bow using Stu's program, I'm almost dead on with a 185 grain point weight, but again, I had arrow drop at 18 yards. With a 180 grain point weight and lowering the brace height from 7 3/4" (7 12/16") to 7 11/16", there is no noticeable arrow drop out to 20 yards and the arrow hits where I'm looking. I will add, Blacktail TD recurves love a stiff arrow so bow design also has to be considered.

To sum up; some of us old codgers here on TG, still have a few tricks up our sleeves.         :D

[olddogrib]

Night Wing,
We weren't really interested in speed either, just curious that if brace height extremes affected spine, would it show a few fps measurable difference from the most "efficient" brace height, i.e. the conditon that delivers the most energy to the arrow.  I, like you, opted for the longer power stroke theory associated with low brace height. The dissenters argued that it had nothing to do with power stroke but was dependent on the angle of the arrow outside of the strike plate when it leaves the string.  If that's true a lower brace height riser (not cut past center) would require more parodox to clear, because the tail end of the arrow is released closer to the riser. But if this theory holds true, for a given arrow leaving with perfect paradox, if you reduce brace height it will act slightly stiff and if you raise it the arrow will act slightly weak(or the exact opposite of what I thought).  Spine is spine ought to react similarly regardless of composition. Both my bows are cut 3/16ths past center and I'll admit I can't tell any difference in arrow flight when moving brace height within the bowyers recommended range.  I tune for quiet and mine seem to do better on the low end of the range.

[chuckbow]

Interesting , FYI:(@ 60ft) if my brace hieght changes 1/8 of an inch less ,i get one inch left, if its 1/8 inch more height i get one inch right.this is my observations ,on most every bow i own! some, more! also ,has taken me 20 yrs to figure this one out .

[Doc Nock]

Varied bowyers and shooters taught me humility when I got back with stick bows 18 yrs ago.

As one put it, "just because it doesn't have bolts and levers, never mistake tuning a stick bow as 'simple', there are many complex variables at work with finger shooters and sticks!"

That 3/16" past center cut riser has a LOT to do with your BT's like stiffer arrows.

I recently shimmed my sideplate out a good bit. As another trusted bow guy put it, "With center cut or beyond, your shaft doesn't quite know whether to go left or right off the shelf in paradox, so does one or other and can cause hinky results."

[Night Wing]

olddogrib,

I'm below the recommended brace height of 7 3/4" (7 12/16") -8" my bowyer recommends for his 66" take down recurves since my brace heights are 7 9/16" and 7 11/16". I'm also shooting 12 and 13 strand Dyna97 bowstrings instead of a dacron bowstring. Lastly, I'm shooting a 66" take down recurve bow with a 19" riser and 23.5" limbs instead of a classic shaped longbow or a hybrid longbow. My bows may act differently with regards to spine since they're only 42# and 37# shooting 32" BOP, 637 grain and 550 grain aluminum arrows.

On a wild hair, I lowered the brace height again by 1/2 twist on both bows, but kept the same point weights for experimentation and shot a few arrows this morning for 30 minutes. The arrows out of both bows were hitting slightly right to where I was looking at at 20 yards and both bows are right handed bows. I went back (raised) to the brace height settings in this thread and the arrows went to the left to where I was looking.

[olddogrib]

NW,
I shoot 6-strand, D-10 SBD skinnies on 60", 48# recurves, but I don't doubt what you're seeing and if it only takes 1/2 twist to affect paradox your form is way more consistent than mine.  On good days when I'm really "slapping shafts" (honestly not that often), I've played with +/- 1" BH adjustments and directionally would see the same effects you did regarding point of impact.  My apologies to Chumster for dragging this post off in the bushes and probably providing way TMI! I'm just intrigued with this topic because from the posts I've read here and on the L-wall, it seems opinion is divided about 50/50. I keep wondering, as Doc pointed out, what other factors am I missing?