Centershot is a crucial factor...

[NDTerminator]

Winter being the time to fiddle, here's an educational experiment for you to try...

Enter your bow & the arrow it's tuned for's data into Stu's Calculator.  Now start changing the centershot data both in & out 1/16" at a time. Viva la differences!!!

To get the correct base centershot data on my CM's, I contacted Cujo and got the word straight from the bowyer's mouth, -1/8". I then measured their centershot as I have the H2s set up using a T-300 rest with the spline point removed & replaced with a small piece of rug rest, between +1/16 & +1/8".

Absolutely astonishing have much difference in dymanic poundage there is between -2/16 and +2/16 centershot!

[SlowBowinMO]

Absolutely!  Shelf depth is very crucial in determining spine and is unfortunately overlooked by a lot of newer archers.  In my experience the center shot is second only to actual draw weight when trying to determine the correct spine.

[lt-m-grow]

Originally posted by SlowBowinMO:
Absolutely!  Shelf depth is very crucial in determining spine and is unfortunately overlooked by a lot of newer archers.  In my experience the center shot is second only to actual draw weight when trying to determine the correct spine.

Put me into that category.  I have been learning this "simple" traditional stuff for 5 years now and I didn't realize this until playing with Stu's calculator a month ago.

[Tyke]

So can anyone tell me how to measure centercut on a bow?  A just recieved a new to me Morrison Dakota. The eyeball test tells me it is cut to or slightly past center, but with this measurment being so critical, I would like to be able to measure it accurately.  Even if I contacted Bob and he told me where the bow was cut to, there is a side plate on it now and would be different from where he initially cut it to.  Anybody know a good way to measure this accurately?

[David McLendon]

Take whatever Bob tells you say -3/16" and subtract the width of the strike plate say calf hair 1/16" which would give you a center shot depth of -1/8". IF your bow is cut to zero  or less then add the width of the strike plate,example bow cut to zero plus 1/16" for strike plate thickness is +1/16". Cut past zero subtract the strike plate width, cut to zero and above add the strike plate width.

[Tyke]

So you can't really measure it, you just have to do the math then?  Well that's not too hard, guess I'll have to get a hold of Bob and see what he says.  Thanks Dave.

[moebow]

What I do with mine is draw on paper a straight line on both sides of the bow from top fade to bottom fade. This takes some fiddling to hold the bow still and get an accurate and tight line. The fade area on most bows is the widest part and the handle regardless of it's shape is inside these lines. Then, calculate the center of the two lines and make another line parallel to the first two. Now, place the bow between the lines again (so it won't move) and using a small square, CAREFULLY move it to the strike plate and make another mark on the paper where the square is directly below the strike plate. Now when you remove the bow you can see where the strike plate surface is in relation to the center of the bow. That's your measurement.
This can be agravating but extra hands help hold things still.

Bottom line is: half the width of the bow at the fades is the center line and a square line to the paper at the strike plate will give you the measurement. The more carefull you are the more accurate the measurement. There's probably an easier way but I don't know what it is and the above works for me and gives good results with Stu's great calculator

[Bill Carlsen]

That is precisely why the same arrows will not often shoot well out of several different bows of the same weight.

[pcappy08]

Wow learn something new every day here!  Any one have any idea how a shrew classic hunter is cut?

[Tyke]

Thanks moebow, I'll try something along those lines, because I can call Bob, but Ben Pearson is another matter entirely.  Good idea, I was thinking of measuring the width and doing some math but couldn't figure out where to measure from on the grip area.

[George D. Stout]

Spine should be one of the first things we learn about when shooting a bow and arrow.  A session with a selfbow with not sight window will give us a big clue as to what spine entails.  We sure can take a simple thing, like an arrow bending around a bow handle, and make it complicated 8^).  

If there is a big fat guy, sitting in the aisle seat...and he will not move, you must be very flexible to get around him to go to the bathroom 8^).  If he is a little, pencil thin fellow, you can buzz right by with little adieu.   Spine!

[MSwickard]

the +/- of center shot is the main reason most cannot get good arrow flight.  Stu's Calc. sure help in this dept.

Mike

[daveycrockett]

Originally posted by MSwickard:
the +/- of center shot is the main reason most cannot get good arrow flight.  Stu's Calc. sure help in this dept.

Mike

The +/- factor is also why so many don't get good results using the calculator IMHO.

[wingnut]

Measuring it on a TD bow is fairly easy.  The limb bolts are in the center of the bow.  Extend a straight edge or string between them and measure from that line to the cut of the riser.

Make sure to adjust for thickness of strike plate.

Mike

[Bruce Martin]

So, to be sure of definitions, a bow cut exactly to center would place a skinny carbon arrow about 1/8 inch beyond center assuming 0 strike plate thickness? And one cut -1/8 would place the arrow at 'top dead center' with 0 strike plate thickness???

[Jerry Wald]

So what happens with a tapered shaft - Real thick at the point end and thinner at eh nock end?

This is my first go at these - Safari's and I just ordered so AD's to try with the new bow I am getting.

I know the ACS will be cut 3/16" past center.

Jer Bear

[moebow]

No Bruce,  just the opposite!!!!!!

[legends1]

I dont know if this will help..but,when i cut a riser block i first cut to center line.Then i rasp the window and shelf for radius.When that is done it will be just 1/16".Finish sanding will be aprox.1/16" total now of 1/8".For our bows we will add a velcro rest.aprox.1/16"So now center shot is aprox.1/16" past center.allowing a larger varity of arrow choices.Now all that being said.If a bowyer  crafts a riser finished to center cut and the arrow rides outside of center arrows can still be tuned to the bow to correct the pardox.Bows have been crafted for years cut to center or less.Also with all the arrow choices today there should be no reason to have a problem with proper arrow choice.Back in the day it was simply wood arrow spine.Most bows in those days were cut center or less.
I do craft my bows to center because it does give arrow choice advantages,but i would not discourage someone away from a bowyer who cuts to center.Some very good riser designs out there are best cut to center for strength.If i got long winded sorry.
Mike

[Kenneth]

Yeah, I found out that's why all the arrows that should be perfect or underspined for my bows are actually overspined.  Makes a world of difference when you put the correct centershot into Stu's calculator.

[swampdrummer]

So, are we measuring from the actual center cut or where the arrow rests against the side plate? With my shrew and I'm sure other bows, the side plate is not cut at a 90 degree angle to the rest.

If my thinking is correct then the center shot will change with every change in arrow diameter?

I guess I'm still not real clear as to what the arrow is trying to paradox around. Wether its the point that the arrow is touching as it sits on the rest/sideplate or the riser as a whole. I relieze it has to clear the whole riser. Is the arrow trying to clear the actual spot on the side plate that it rests against? Hmmmmmmmmm