Where IS the center of a recurve bow???

[King Custard]

If shooting through the center of the bow is one of the fundamentals of tuning...where the hell is the center???

If risers cannot be made straight,
if drillings- and therefore bushings cannot be dead central
and limbs too are not 'precision die cut'...then how do you find 'center'?

I've had , before, those who supposedly know what they're doing say to throw the bieter alignment gauges away- cos they only show you the center of the limb -at that point they are fixed to...and that we want the string centered to the whole bow...

And I've seen some use lasers to find the center of their bow...
But if the riser isn't straight and true - bolting a laser to it wont give you center either.

I'm more confused the more i think back on a recent conversation.....
Last week...with a very reknowned and successful bowyer....he took one look at my riser and new limbs and said - "your limbs need centering!"

Wonderful I thought, Ive always worried about that!
He told me of production procedures and the multiple margins for error etc etc.....absolutely fascinating...
'I thought the limbs and string were centered' I said...
" you don't have the eye of a bowyer!"

Fair cop - I don't!
But conversation turned and went on...until he handed me and my set up to another highly knowledgeable feller who set about centering the limbs for me.

And adjusted they certainly are! - from arrow tip on the left of the string ( as you look at it from behind), now, to the right of the string...and so requiring plunger adjustment...
anyways.......

Now im home and doing a basic tune in the garden at 15 yards to see what I can get done rather than rely on sundays weather being good enough to tune properly...

- and I cant get these new arrows to spine ( well, I could..i could undo the limb bolts until they're about to fall out!..not what I had in mind to do as I need the poundage for 100 yards with a short 26 1/4 inch DL to button center, and a short pupil to chin anchor distance. These damn arrow show they're persistently weak!

My button is rock hard- and I really dont want it to be THat hard!
Looking down *What I'd call center - center of limbs/center of bushings* - my sight aperture is dead center of the string ( when I want it to the left of the string for a good string picture)
My longrod is slightly left of gold at full draw...
My arrow points are left of the string- and some...tried everything from dead center to 'outside the longrod'
And it still wont shoot anything but right of gold!! - bareshafts even 'righter'.

And yes - I've tried all manner of braceheights between 8 and 10&1/2 inches with different strings.

I wanted ACE's to shoot 66 inch Apex Carbon Limbs, FF string , 27&1/4 inch ( groove to tip of point) arrows, with heavy 100gn total points - pulling 38.5lb at 26 and a tad inches.

My reckoning on 670's ( when my 650 X10's were slightly stiff)- possibly even going for a slightly longer 620 --- got thrust out and I came home with 720's - They're too weak aren't they?

OR - am I just not centering the bow on the same 'line' as this highly acclaimed retailer and bowyer???

So before I 'Prove' to the retailer, that they are untunable....
what are your thoughts :

on Bow center - lining string up with what???
On the easton charts- and the retailer convincing me to go with 720's???
and
On who should bear the cost of replacing these with the proper spine???

BTW - this retailer - or at least the guy who served me, doesn't believe in bareshaft tuning...and has actually completed the easton Arrow course...was massively helpful, polite to a fault, fantastic service, even doing a great deal from my perspective.........

Only I can't get these arrows to work off my bow. even at 15 yards
Tomorrow I'll try again outside - but even with 20grain lighter points i can't see them being anything other than...a waste of money due to wrong spine choice.
That or maybe the bow has been incorrectly centered??

[pHz]

Originally Posted by King Custard

I've had , before, those who supposedly know what they're doing say to throw the bieter alignment gauges away- cos they only show you the center of the limb -at that point they are fixed to...and that we want the string centered to the whole bow...

as a 'layman' (ie - not experienced enough yet to know whether or not im talking out of my bottom here) -

surely we DO want the string centred down the limbs (regardless of whether thats also the centre of the riser) ?

if the string doesnt run down the centre of the limbs then presumably the limbs arent being put under tension in the line of desired arrow travel and surely then the arrow is being laterally affected as the limbs move slightly sideways to return to their resting position ?

(surely we use centreshot position and button pressure to compensate if the line down the limbs isnt the true centre of the bow - which presumably on a recurve wouldnt matter anyway due to paradox ? - even if your arrow was lined up down the centre of the 'whole bow' paradox would still bend it away from that line on release ? )

(just thinking out loud - might be total male secretion of course)

slainte : rob

[buzz lite beer]

You sound like your on the edge of a panic attack string has to run down the centre of the limbs and through the centre of the grip everything else is irrelevant (including long rod) if when you have got the string running centrally and you look down the string (align the end loop servings up) if the limb tips are also lying centrally your bow is straight enough to shoot better scores than any human is capable of. If you can't meet these criteria then perhaps there may be a slight twist in the riser and shimming the limb pocket to compensate may be required, also scrutinise the string nocks on the limb tips many are hand cut and often one side is marginally higher than the other inducing a twist, excessive string twists and string construction, all can influence limb alignment also. when checking your alignment place the back of your head against the wall it aids consistency when flicking your eyes up between limb gauges.
and if you're arrow are still coming out weak can you not reduce your point weight, extra stands in your string, use large groove nocks try moving your button out some and then back the pressure off to compensate before you rush out and replace kit perhaps needlessly.

[pHz]

illustration of what buzz says here -

http://www.perrisarchery.co.uk/Perri...%2005%20Q4.pdf

slainte rob

[TWIW]

OK.

Lets get the limbs aligned;

Get 6 sticky labels. Stick 3 on each limb: 1 near the tip. 1 in the centre of the limb 1 at the fadeout of the limb Fix the longrod to the bow. Measure the width of the limb at each of the labels and mark the centre with a black fine felt tip.

Rest the bow over a chair where the longrod goers over the back of the chair and the lower limb rests on the seat of the chair.

Now stand back and look at where the string lies in relation to the marks you have made. Align the string through the limb adjustment bolt/allen keys on the riser and check the string against the marks. If the limbs are not aligned thre string will not go through the centre of the limb adjustment bolts etc and will not follow the marks on the labels.

If they are not aligned make the alignment adjustments to move the limbs left or right to get the string to run down the centre of the bow. These adjustments are likely to be very small as you are effectively moving the limb tips left or right a fraction.

Once everything is in line tighten it all up.

Tuning your arrows. Is a whole new ball game .......

[cestria]

I've just watched Simon Needham's DVD. The first part explains this very well and how to achieve the centre of limbs and centre of the riser paradox. It does appear to me that true perfection may not always be attainable, so you may just have to get as close as you can and be happy with this set-up and not beat yourself up too much.

[geoffretired]

Imagine a very simple bow made from a long, straight and thin length of wood, 1/8" round. Line up the string with the wood by standing behind it, in the right position. Job done!
The odd shapes on the modern bow simply get in the way of the process.
On the simple bow, the string loops, limbs, and importantly, the pressure centre of the grip are all on one line.(by default)
Imagine next, the simple bow shape, overlayed onto the bow you are using.It will appear as a 1/8" wide line down the inside surface of your bow.Ideally you would want that line to start at the middle of the limb tip, travel down the centre of the limb, continue through the pressure centre of the grip, on to the other limb and along its centre line, to the other limb tip.
We cannot overlay the simple bow shape onto your bow, so the line of your string is used as a visual aid to "see" a straight line and how well that fits.

[WhitehartFB]

Originally Posted by pHz

illustration of what buzz says here -

http://www.perrisarchery.co.uk/Perri...%2005%20Q4.pdf

slainte rob

It's Page 3/4 the Jay Barrs article.

As Buzz says: it's the limb tips being straight and the string running down the centre of the limbs that is important.

It is also worth checking this each time you string your bow, the physical screw/washer adjustments will not change, but stringing the bow can twist a limb.

At a recent Beiter Dealer conference we were the only dealer that said we did not sell their limb guages because they were not used correctly and caused too much confusion. They then showed us a new device to be launched soon which will make the job a lot easier and more accurate.

[Huffy]

Originally Posted by Whitehart

At a recent Beiter Dealer conference we were the only dealer that said we did not sell their limb guages because they were not used correctly and caused too much confusion. They then showed us a new device to be launched soon which will make the job a lot easier and more accurate.

That sounds interesting, any idea as to when the device will be available. I have found that when you ask a group of archers to check the alignment of a bow string and the arrow centre shot you get as many different answers as archers in the group.

Best wishes, Mark

[King Custard]

erm - um......dur...


It's me...my fault...I don't have the eye of a bowyer.
I was wrong to question, wrong to guess too weak an arrow choice. Wrong to query poor centering.
Wrong to panic.

So there you go - big enough to admit I was wrong.

I' ve learned though- to only use this years prescription glasses not the old spares that were easier to find and whose frames were twisted. I've learned to set up center shot in good bright light. ( my excuses )

I've learned that having even a slightly 'off center' string alignment can produce a marked lack of power output in a bow- AND even make it seem like the Wrong spined arrows are the right ones!!!!

I've set up my new limbs and arrows now - and basically bareshaft tuned up to 60 yards with only a 5 grain reduction in point weight...giving 95grains point and insert weight for a 14.8% FOC.

And I'm fairly chuffed now.

Except that at 80 yards bareshafts are outside the group by a foot or so...don't think I'll worry too much about that though eh?
Bit o' micro tuning, some better weather, and a little more practice and I'll have those Bowman scores no probs this season!