Straightarrow

I may be misinterpreting your statement, but if you are testing spine, you should be using a bare shaft. If they are weak they will will fly right. If you're doing a walk-back with fletched shafts, adjustments are usually made to the rest position. Spine tests should be done before walk-back tuning tests are started. Even if you didn't do it correctly, I would still expect the weak fletched arrow to fly to the right, the farther back you go.

RobVT3

How do you determine the centerline of the bow? Do you measure it from the riser? I shoot a Mathews Legacy and I believe they say it is 13/16" from the riser. Should I start with my whisker biscuit there?

Arrroman

To find the centerline sit down and rest the bottom cam of the bow on your leg, then sight the bowstring through the center of the upper wheel and follow that line down to the grip.

What you will probably notice is that the grip itself is not centered, but offset to the right.

Most of the time the sight pins will be oriented to the centerline, but the rest itself will tend to be about 1/8" to the left of the centerline for the bow to shoot its narrowest groups.

Good luck hunting! >>>------------>

Dryridge

I'm an oldtimer when it comes to bow tuning. Been doing it since limbs had brackets bolted to themwith the wheels (now called cams) attached to them. I see lots of good advice on here for tuning, and eyeballing centerline but not a FINISHED tiller adj.
Tiller and Nock must gohand in hand. Here's my methods:

1. 2 cam bows (older style): turn limbs until bottomed out and then decrease evenly no more than 3 turns at a time each, until a comfortable draw wt is attained. Here is the best advice through this whole thing FORGET WHAT THE SCALE SAYS. Comfort is more important. Now set the limbs for even tiller measurement from the back of the limb where it leaves the riser to a point on the string where the square or other measuring device passes the string as you swing in an arc keeping the end of the meas. dev. tight on the limb/riser. Now set the noc pointor string loop and noc an arrow. Next, make a small mark at the point where the cam and string meet. Next have someone watch and someone S-L-0-W-L-Y begin to draw. (I used to do it in a full length mirror, but it is better when someon watches) Watch which mark leaves first. Loosen that limbs bolt 1/2 turn until theyboth leave at the same time. This isconsidered TIMING a bow.You can do this in smaller increments until perfect. NOW set the nock to 3/16or 1/4" above sqare using the rest mount hole in the riser as a centerline. Or attach a string loop. Now you should be square but try the drawing process again, watching your marks. It doesn't matter now ifmarksare exactly at the string/wheel junction at this point....just make sure they both move at the same time. NOW paper tune the bow USING THE REST TO MAKE ADJUSTMENTS...I can't for the life of me figure out why someone does this process by setting a rest out of place then making the bow out totime to match the rest If you can't tune it by the rest, then you needa rest more in TUNE with your skill level. I truly think this mistake all started when people boughtmicrotune target rests for hunting bows and didn'tknow how to set them up properly. Of course if you are using an old stick on ornon adj. springy rest you do itby ARROW SPINE.

HINT>>>You may also find that your bow will group best past 10yds with an inch high, inch left tear at 7ft. Give it a try....this tip was given to me on the shooting line at the worlds in Vegas by the most highly regarded spot shooter ever....Hint, he made a Wheaties Box. Improved my xrings from 51 to 59 and the one miss was me!!!


2 SINGLE CAM. Use the same basic process as above, except....Set the tiller using string pulled tight from axle to axle as mentioned above...THEN...make the marks on the cam this timeATFULL DRAW. Now adjust according to which one starts to go forward first. This one will seperate the men from the boys, or tell you if you are overbowed.Again be sure your nock is set at 3/16" abovedeadcenter andhave an arrow nocked at all times and pointed in a safe direction. Also be sure to useYOUR release.

HINT>>>> The newer model 05 newer have centerlines built into the laminations of of the grip. They are dark grey lines I believe.

This should help you get where you need to be.

If broadheads won't shoot then spin them first. If they spin true, check your arrow spine by trying a size or two up and down the scale. This is easier than screwing the whole thing up by trying to tune them andfind outlater itwas a spine problem.If that fails....PAPER TUNE THE THING ALL OVER AGAIN.

HINT>>>> This one I saved for last because I didn't want crucified yet.....Bare Shaft Shooting is OVERRATED....who hunts with bare shafts???? TUNE IT WITH WHAT YOU ACTUALLY SHOOT. Yes, Before you flame me up, I know the reasoning...but still, why check all those points when fletching CHANGES THE SPINE ANYWAY. Do youreally think adding the wt. and drag on that shaft doesn't change things???

WELL, here is 30+ yrs of shooting and tuning experience the best I can tell it.
If something is unclear, post or better yet shoot me a PM.


Dave

Arrroman

KW,

My best friend gave me a copy of the Easton Tuning Guide 35years ago. I used to keep it under the cover of my Webster's dictionary.

I did download the Pdf version from Easton a few years ago and it hadn't changed by much.

They never did address balancing tiller by using adjustable limb bolts.

Simply put, the nock point height that is necessary in order to launch a level arrow is determined by the bow's tiller.

A higher than 90degree nocking point will require additional tiller on the lower limb in order to launch a level arrow.

A lower than 90degree nocking point will require additional tiller on the upper limb in order to launch a level arrow.

So whether the arrow runs uphill, or downhill to the rest, there will be a tiller combination that can launch a level arrow from the bow.

The original whisker biscuit was a full circle of bristles that encircled the arrow. It was a slightly larger diameter hole than the diameter of the arrow that was to be shot through it. And the tiller combination that does not create either a rising or diving arrow from the bowstring is even, which work well with a 90degree arrow on the bowstring.

The newer whisker biscuits work the same way.

The difference between banging the arrow against a rest or having that arrow leave the bow clean is often a matter of tiller.

I have several buckets of arrows that are underspine for what I would use for hunting. But if I lower the draw weight of the bow to match those arrows I can still shoot them for targets. And being able to properly tiller the bow means you can leave the nockpoint alone and tune the bow with a wrench.

Good luck hunting! >>>------------>

Arthur P

If you're talking about just barely moving the nocking point to clean up an almost perfect paper hole, then I can go along with making a small tiller adjustment. If you're talking about moving the nock point 1/8" or more, leave tiller alone and move the nock point.

Personally, I don't mess with my tiller once I get it where I want it. I make all my tuning adjustments with the rest and nock point. It's a little more effort to do it that way, but I want it right.

Also, I get my cams timed and/or synchronized by twisting the cables instead of messing with tiller. We had to do that tiller thing to some degree back in the days of steel cables, but it's not necessary any more. You can now have perfect tiller AND perfect timing if you want it.

Dryridge

ArthurP is right as always. I have the utmost respect for his advice and agree with 99.99% of it. I didn't add using the cable twisting because I figured the ones with a press already knew that and the ones without a press don't need to be trying it.

I think if you see what he and I are saying about Keeping one TIMED while working on the TUNING, you will see that it is very important.

Advice that should be heeded by all newbie bow tuners and those that have been taught to papertune with the limb bolts.

Dave in WV (formerly DBOWGUY, arthurp Remember me now??)

Arrroman

In an ideal world the bow will be assembled with the limbs matched, and the cam(s) in time, at maximum poundage, and everything in spec as per brace height and axle to axle overall length.

Any bias in limb weight will draw the bowstring to the end of the bow that pulls more weight.

This method I postedissimple. Its testable. And it works.

I like being able to look at the bowstring with an arrow on the rest and know instantly whether or not the string has stretched or something has changed, and when you have even tiller and the arrow is at 90degrees you can see real quick if something is out of line.

When I replace strings and cables on my bows I always set the bow up to factory specifications at maximum draw weight.

I don't use brass nockpoints on my bowstrings anymore. I tie a permanent double serving about 1/2" long above the arrow and it doesn't move. Once you understand how tiller works you don't have to move the nockpoint.

Good luck hunting! >>>------------>

Straightarrow

How would using tiller to adjust timing on a single cam work? On my single cams the timing position is measured with the bow at rest. Changing tiller does not affect it's position. Changes to timing are made by adjusting cable and string lengths on a modern single cam.



Using that logic - who hunts big game with field tips? Yet, many tune with them. I'm guessing all your tuning must be with broadheads? Actually, that's not a bad idea as long as you don't bare shaft with broadheads.

No flame here, just disagreement. I've bareshaft tested hundreds of arrow groups. I use to add an equal weight of
masking tape to the fletched area to make up for the lack of feather weight. That is, until I realized the 5 grains was insignificant and they flew and tested the same. If you're using some heavy 20 grains fletch, I would recommend adding the masking tape. It works. There is very good reason to bareshaft test - it enables you to easily get broadheads flying right with fletched shafts or bareshafts. In other words, the broadhead tipped arrow will not plane to a different point of impact.

How a person can get proper spine from a chart and paper holes is beyond me. I've never been able to do it and I don't see anyone else can. I can get close, but close doesn't cut it when shooting broadheads - literally.

Arrroman

I don't bareshaft test. I did, but I don't bother anymore.

Proper spine arrows will fly in a straight line from the bow. and improper spine arrows don't.

Most arrows will hit real close at 10-15yards but that doesn't mean they are of correct spine for your bow.

And the situation gets worse when someone of limited skill and competence decides to screw on a broadhead and take a shot at a deer at 25yards and finds he shot a footor more away fromwhere he was holding.

I reccomend rubber blunts and shooting the bow at 100yards for a reason.

Proper spine is what proper spine does. (I'll give Forest Gump credit for that one.)

Go ahead and put a box at the base of a telephone pole at 100yards, and see if you can hit it when you have a nice long vertical line above the target to sight on.

I want people to learn and understandhow the bow and arrow works.

Success creates confidence and confidence is a good thing to have.

Good luck hunting! >>>------------->