# Plunger tension



## m013690 (Sep 3, 2011)

You seem to have the idea, but you're confusing step 1 and 2 as two competing alternatives. The VERY basic concept of bareshaft tuning, even though it's still a point of debate amongst some, is this BASIC process:

Phase 1

1. Set plunger TENSION to ROCK HARD firm (replace spring with a matchstick so there's ZERO give).
2. Set plunger POSITION to DEAD-CENTER, so the arrow looks right in line with the string down centershot.
3. Shoot fletched and bare shafts and adjust limb weights (with limb bolts) and/or arrow components (point weight, etc.) to get the bare shafts to impact with fletched.

Phase 2
1. Set plunger tension to a medium setting (middle weight spring and about middle of the in-out spring tension adjustment).
2. Set plunger position to place arrow centershot just outside (left for RH archer) of the string (base of the point should be just appearing to touch the string down centershot).
3. Shoot bare and fletched shafts and adjust plunger tension to get the bare shafts to impact with the fletched.

Recognize there is a bit more to it than that, and the list of things you can adjust is very long (string weight, strands, material, nock point (brass or tied-on), fletching weight, size, wraps, point weights, etc.), but this is a basic premise of bareshaft tuning. As I understand it. Took a while to get the hang of it, but my new arrows are finally tuned BEAUTIFULLY, and it was well worth the time, trouble and frustration to learn it.

Best of luck,

Ted (me, not you...)


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## TexARC (Mar 5, 2003)

A popular and very well thought out, and perhaps a seminal treatise, on tuning for tens is called, well, Tuning For Tens, by Rick Stonebraker. The document has been on the Texas Website for more than 10 years, and is routinely one of the most frequent "hits" by websurfing archers.

Of primary consideration is what the plunger actually does and why it is used - it is to absorb and buffer/dampen lateral motion of the front half of the arrow upon a slipstream release by the archer. This decreases the size of the barrel the flightpath of the arrow describes on the way to the target, I think. Since most archers vary in release technique A LOT, the influence of the release on the plunger makes it very hard to have a consistent written "advice" that will work for everyone. 
I would suggest that any serious archer work with the plunger, making changes and always trying the eye-doctor technique, "is it better or worse?", and keeping track of the results in a written way. This is one reason why a plunger that has gradients/markings, and clicks, can be so useful in the testing/tuning process.


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## Destroyer (Sep 11, 2009)

I set mine on medium to light and tune from there, I don't want it maxed out, if I do I have no adjustment left in the plunger.



m013690 said:


> The VERY basic concept of bareshaft tuning, even though it's still a point of debate amongst some


There are two different methods that get called bare shaft tuning, one that is about tuning the spine to the bow by shooting a bare shaft and looking how it flies (eg. nock left point poi right of aim point) and what is described by you which sometimes is called 'group tuning'.


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## Robert43 (Aug 2, 2004)

The only way I could tune my bow was to put a match stick trick in the button & set the limbs to the arrows . Then I set my button to 3mm diflection (1/8") with 500graims ( 1.1 lb) on weight on it then do walk back. It worked for me, I tried for hours adjusting the button & all I did was end up with no hair


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## Joe T (Apr 5, 2003)

All basic and fine tuning methods start with the plunger spring tension set at around the value that you are going to end up with at the end of the process. To do anything else would be time wasting and to be honest pretty dumb. This spring tension value is going to be around 300 to 500 gram equivalent say (4-5 Newton) so this the value you start with.

A refinement to this initial spring setting is suggested by Vittorio in his book. You start off a basic bare shaft tune at 30 meters by moving the fletched arrows to the target centre by adjusting spring tension. Assuming you have a good initial sight pin alignment this puts the spring tension very close to the final value. This is a plus as nocking point and button spring settings are interlinked so in theory you end up with a better nocking point setting.

Up front of the tuning process you have a bow set up process where you match the bow to the arrow (or maybe vice versa ). This all about matching arrow
flex rate and speed to the bow geometry so you get clearance, a good string/arrow separation and the arrow leaves the bow pointing in the direction it's travelling. Bow set up usually relates to adjusting draw weight (with a minority preferring to adjust shaft length).Most archers, think, believe that button spring setting is irrelevant to the bow set up process so why not start with the setting you are going to begin tuning with. There's another group of archers that think that locking up the button in some way impacts on the bow set up process i.e in verifying you have or getting to the right arrow and the right draw weight. (never heard anything in the way of a logical argument supporting this idea).

So locking up a button spring relates only to bow set up and not to tuning.

The Tuning for Tens process is the classic example of this. The button is locked up for "bow set up". The spring is replaced before the start of the basic or fine tuning process.


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## atjurhs (Oct 19, 2011)

K.I.S.S. - keep it simple & stupid

1) buy arrows (according to their spine) to match the limb weight and drawlength that I have/use/want.
2) set the bow limbs at that weight
3) insert the plunger with the middle weight spring, and position it so it's slightly left/right of centershot, start shooting
4) adjust plunger tension up or down in order to get bareshafts to fly within an inch or two of your main group
5) if you run out of plunger tension you can change out the spring for a heavier/lighter one, increase/decrease the limb tension, and/or move the plunger position further/closer to centershot

not the most scientific but it's simple, and you get to experience what happens when you tweak something on your bow, that's valuable knowledge!


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