Rookie Question on Tuning

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This topic contains 6 replies, has 6 contributors, and was last updated by gjarcher gjarcher 1 year, 1 month ago.

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  • June 4, 2013 at 1:41 pm #580072 Back to Top REPORT

    Greenheadhunter32

    Joined: 6/4/2013
    Location: MN
    First off I’d just like to say I am brand new to the site, and have already learned more about tuning and shooting then I ever thought I would, so thank you all! I have been bow hunting for quite a while, shooting first a Browning Illusion, and since then a Mathews FX. Both of which were never “tuned” more than quick paper tuning the first day I bought them. They always hit where I aimed (mostly), and that was as far as I went with it.

    I have recently acquired a brand new Mathews Drenalin, with a DL of 28 inches.

    My questions are as follows:

    (1) Is it safe to assume that a brand new bow is set to factory specs reliably? (I have limbs maxed out, ATA is measured at 33″, BH is measured at 7″, the Tiller is the same for both limbs-using a string ATA) so I think it at factory Specs. The CAM timing is a little harder for me to measure because of the two holes it uses to measure it. I took two 3/32 drill bits (the smooth sides of them) and leveled the bow as best I could, and it seems to be correct. I have not checked Idler wheel lean.

    (2) If it is correct (brand new- never shot, measurements seem good), should I mark the cam position with white out or something similar to have a good reference point for the CAM position?

    (3) How many shots do I need to put through it before I can anticipate is “broken in” with the stock string, mechanical release, and should I wait to install a peep site during this process, before re-checking that everything is to specs?

    (4) Can I do a “walk back tune” to get sites minimally accurate during this break-in process, or should I just wait to make sure everything is settled in?

    Thanks in advance for your responses!
    -Matt

    June 4, 2013 at 8:58 pm #580099 Back to Top REPORT
    bow-drawn
    Bow Drawn

    Age: 62
    Joined: 11/14/2007
    Location: Ohio
    View My Bows
    Welcome!

    June 4, 2013 at 10:51 pm #580106 Back to Top REPORT
    trailboss
    Trailboss

    Joined: 9/25/2007
    I don’t have any answers to your questions but welcome.
    June 6, 2013 at 7:39 pm #580422 Back to Top REPORT

    conquestador

    Age: 63
    Joined: 12/10/2009
    Location: Upstate NY
    Welcome!  You’re off to a better start than most.  I’m not the expert that some here are, but I’d say if you launch 100 shots, probably less, you’ve settled your string.  But if you enjoy shooting, in a few days you’re good.  Walk back tuning is one of the simplest things you can do whether your bow is in tune or not.  You may have to make some slight adjustments once settled and re-tuned, but it should be minimal.  I’d go for it.  All you can do is learn from it.  Good luck and enjoy!
    June 10, 2013 at 1:43 pm #580769 Back to Top REPORT
    lunzee
    Lunzee

    Joined: 12/21/2010

    First off I’d just like to say I am brand new to the site, and have already learned more about tuning and shooting then I ever thought I would, so thank you all! I have been bow hunting for quite a while, shooting first a Browning Illusion, and since then a Mathews FX. Both of which were never “tuned” more than quick paper tuning the first day I bought them. They always hit where I aimed (mostly), and that was as far as I went with it. 

    I have recently acquired a brand new Mathews Drenalin, with a DL of 28 inches.

    My questions are as follows:

    (1) Is it safe to assume that a brand new bow is set to factory specs reliably? (I have limbs maxed out, ATA is measured at 33″, BH is measured at 7″, the Tiller is the same for both limbs-using a string ATA) so I think it at factory Specs. The CAM timing is a little harder for me to measure because of the two holes it uses to measure it. I took two 3/32 drill bits (the smooth sides of them) and leveled the bow as best I could, and it seems to be correct. I have not checked Idler wheel lean. Sounds good

    (2) If it is correct (brand new- never shot, measurements seem good), should I mark the cam position with white out or something similar to have a good reference point for the CAM position? have seen it done alot but not required

    (3) How many shots do I need to put through it before I can anticipate is “broken in” with the stock string, mechanical release, and should I wait to install a peep site during this process, before re-checking that everything is to specs?Usually 150-200 shots. I always put peep in but is personal preference. Will have to adjust it again after the break in period.

    (4) Can I do a “walk back tune” to get sites minimally accurate during this break-in process, or should I just wait to make sure everything is settled in? Would not take long to retune.

    Thanks in advance for your responses!
    -Matt

    June 11, 2013 at 5:25 am #580837 Back to Top REPORT

    Greenheadhunter32

    Joined: 6/4/2013
    Location: MN
    Thanks!!
    June 14, 2013 at 10:14 am #581111 Back to Top REPORT
    gjarcher
    gjarcher

    Age: 71
    Joined: 10/3/2006
    Location: Colorado
    View My Bows

    (1)…The CAM timing is a little harder for me to measure because of the two holes it uses to measure it. I took two 3/32 drill bits (the smooth sides of them) and leveled the bow as best I could, and it seems to be correct. I have not checked Idler wheel lean.(4) Can I do a “walk back tune” to get sites minimally accurate during this break-in process, or should I just wait to make sure everything is settled in?

    Unfortunately the Cam Timing Post in the Technical FAQ forum lost all of the images when the forum was upgraded. {#emotions_dlg.mathews_brick_wall} The process of timing the Drenalin cam rotation is to get the holes in the cam to align so that they are parallel to the string, not the bow. Here are several ways to do it:
    a) mount the bow upside down with a plumb bob fastened to a pin in the highest timing hole. Use a line level to get the string plumb. Check the plumb bob string to see if it passes through the lowest cam timing hole … if not, adjust cam rotation so that it does.
    b) here is how I do it with a DIY tool. Fasten two pins and a line level bubble to a short piece of aluminum angle with JB Weld. This is best done with the pins in the cam timing holes and use clothes pins, etc., as clamps to hold the angle in place until the JB Weld sets.
    Use a line level to level the string.
    Dren-Rebuild 016

    Adjust the cam rotation so that the DIY Timing Tool’s level agrees with the string’s level.
    Dren-Rebuild 017

    As for ‘tuning’, I wouldn’t recommend attempting any tuning until the idler lean is adjusted. To adjust/check idler lean come to full draw and have someone observe how the string tracks off the idler. You can’t reliably do this yourself because in the process of looking up it is most likely you will torque the bow and get a false reading … which brings up the point that bow hand grip/torque will affect idler lean, so a good consistent grip is necessary for accuracy.

    If you want to set nock height and centershot so that you can have some confidence in shooting the bow before making idler lean adjustments or cam timing, I’d recommend doing a Short Distance Tune.

    First, check that the arrow rest supports the arrow at the berger hole (rest mount bolt hole) in the full up position. Then set the nock height at 1/8″-3/16″ above perpendicular, and set the centershot at 13/16″ from the riser (11/16″ for most fall away rests), this is just a good initial setting to get started.

    QADnockheight

    Centershot

    Short Distance Tune is an easy, quick method that doesn’t require any special equipment and can be done indoors at 12 yards even without paper tuning. The procedure is explained on page 8 of the Easton Arrow Tuning and Maintenance Guide. After cam timing and idler lean adjustment, paper tuning and walkback tuning, then moving on to more advanced tuning methods like Fine/Group Tuning and Broadhead Tuning can be done with confidence and good results.
    http://www.eastonarchery.com/img/downloads/software/tuning_guide.pdf

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