Arrow Tuning

[fz4vgq]

Do you find Stu's Calculator to be accurate compared to what really works with your bow ?  I ask because I've been plugging in #'s for the last two days to see the differences. My local archery shop (the owner is a traditional shooter) is telling me my #'s seem to be way off. I'm on a tight budget so I only want to buy a dozen arrows at this time. I just don't want to spend $$$ and have too short of arrows right off the bat that I'm not able to cut/tune.

Stu's calculator is telling me a Beman MFX Classic 600 cut to 27.5", 125gr point, 75gr HIT insert, 5" feathers is 49.4 spine with 9.2GPP for my bow specs. Depending on what string choice I enter for the bow I get anywhere from 45.7 (B50) to 51.7 (8 strand fast flight). Bow is 58@28 or 49@25 for me.

Any thoughts for this new guy ?

Thanks,
fz

[joe skipp]

You guys make this way to complicated...   :confused:    

[fz4vgq]

:D    I know I know..... it's the engineer in me      

I'm just gonna get them cut a little longer than Stu's calc shows to be on the safe side.

[Muleyslayer]

Chad most of these guys will help the most they can, some get frustrated on techy questions.  I;m shooting axis 400 @ 29" long w/145 tips and regular aluminum inserts out of my 53#@28" long bow, with 4-4" sheild cut feathers and it shoots pretty good. stus cal. wasn't even close for me but works for others.  what works for me may not work for you. If on a budget go with woodies, these guys love'em and they are easy to tune, I'm sure one of the big boys will chime in and help you out. Good luck and have fun.      

[Buckwheaties]

Stu's calculator works good for me but MAKE SURE you enter the center cut correctly. a 1/16 " makes alot of difference in the calculations, an 1/8, a whole bunch.

[Double Tee]

Stu's calculator has worked fine for me on my recurves. But I got some new 1916's for a new Martin Savannah. I can't get them to fly at all! I keep measuring it at 1/4" from center,does anyone know what a Savannah is supposed to be?  

[ishoot4thrills]

Originally posted by Buckwheaties:
Stu's calculator works good for me but MAKE SURE you enter the center cut correctly. a 1/16 " makes alot of difference in the calculations, an 1/8, a whole bunch.

Can't stress this enough. It's the most important entry on Stu's calculator. Get it close with the calculator and then fine tune your centershot by adjusting the thickness of your side plate. I find it best to start out with arrows slightly on the weak side. Then you can add material to your side/strike plate to make your arrows act stiffer. This has worked very well for me with multiple bows using the same arrows.

[hkmp5]

Hello FZ,
The DSC works well for me.  Just one thing to note that a lot of guys miss.  With an HIT insert you have to account for the extra internal length.  I shoot those also and have found that 1.5" in the footing field  works well.
-Stu

[Muleyslayer]

Told you the big boys would come out!!!!!!  

[fz4vgq]

Thank You all.  

Muleslayer, totally understood. I do my best to avoid the "whats best" questions   :D

My main worry is that with the HIT insert being so long (1.5") and seating so deeply in the arrow shaft that once they are in there really isn't a way to cut the shafts a little bit shorter to tune.

[nightowl1]

This is how I have used the calculator....

I use it to get the right shaft... I then tune the arrow to the bow ignoring the calculator. After I have found the right tune I plug the numbers in to find the dynamic spine.

This way if I ever want to make changes or find a new shaft I have a really good idea of what will work

[Smallwood]

straight from the man himself-

Originally posted by hkmp5:
Hello FZ,
The DSC works well for me.  Just one thing to note that a lot of guys miss.  With an HIT insert you have to account for the extra internal length.  I shoot those also and have found that 1.5" in the footing field  works well.
-Stu

also , if your worrying about being able to put in / take out your hit inserts... just use hot melt to put them in while your tuning your test shafts. (screw in your field point into the hit insert and hold the fp with some pliers, heat the hot melt over a plumbers torch or gas stove burner and apply it to the insert and then heat the insert with the glue on it a little and then insert into the shaft in a twisting motion. Dunk in water to cool.) Now, if you need to cut more off your shaft, just apply heat to only your field point(not the shaft) and then with a twisting motion, your point/insert will come out.

[metsastaja]

I have now tuned 6 different bows both recurve and longbow using stu's calculator with great success.

Both bows tuned using Stu's Calculator. Neither the archers or Hogs complained

 

Center Cut..I think this number is the most critical and guesstimated the most. call your bowyer or use the example given in the directions pdf.

String type and count. Another important number.

Internal footing..here is where I realized I was getting carried away.  

  I sent an email to Stu  
   

I am using both 50 and 100 g inserts that extend beyond the arrow front by .200 of an inch.
The 100g insert is 1.415 inches total. Was wondering how you would input this into calculator.
How would you treat the .200 re BOP.  I plan to use .9  of as insert length and remainder as footer.  Still need to figure out the weight distribution.

I know I am getting carried away but it is fun breaking this down for other posts.
 

Here is his reply

   

Hello Les,
Good to hear from you.  I am still working on the next upgrades so thank you for your patience....I haven't forgot just been too busy at work!
 
The 0.2 beyond the front should have no effect on the dynamic spine and can be disregarded.   The length internal is entirely different and does need to be considered if longer than the 0.9" you referenced.  For the 100 g insert I would figure it like this:  1.415 total - 0.2 in front - 0.9 default length = 0.315 of "extra" internal footing.  That will likely only add about 1# or so to the dynamic spine.  I would keep the total 100g in the "Insert" field.
The FOC may show a bit less than the actual measured value because the weight is hanging out there a bit more than usual but it should be a fairly small difference.
   You are preaching to the choir there brother when you mention getting carried away with this  ......I do the same and also consider it fun.  Like you I answer a ton of questions, pretty much daily now from all over the world.  Helping others is good work and every now and then someone will question me as why I do it.  That is an open door to share Christ's love in my book!
 
God bless,
-Stu  

And don't forget bare shafting..http://www.acsbows.com/bowtuning.html

Calculator is available at  http://www.heilakka.com/stumiller/

[FrankM]

Question about centercut:
When rest touches the right side of the string, not centered on the string, is that considered
-1/16 or -1/8?

[fz4vgq]

Thank You all again. I've learned some very valuble information from each of your replies.

[Smallwood]

How to measure centercut-
 

[FrankM]

Excellent. Thanks.

[fz4vgq]

Thank You for the picture/diagram Smallwood. It has me thinking though..... that way of measuring would only work if your bow is cut past center correct ?  If the bow was 1/8" or 3/16" shy of center wouldn't the straight edge be hitting the riser before touching the string taped to the center of the limbs ?

Seems I've seen a picture here of someone using a crafstmen laser level bisecting the centerline of the limbs with a piece of paper taped to the riser somehow to show the laser line either on the paper (if the shelf is cut past center) or on the riser if it is shy of center. Anyone else employed this method ?