spine/arrow question

[rolltidehunter]

my bow: 53lbs @ 26 1/2 inch

i am trying to bareshaft my arrows.

heritage 250's and 150's are two stiff,

i got test kit with a heritage 90's and gold tip 1535's

what lenth do i need to cut them and how much weight should i add.

gold tips are 7.g gr per in
heritage 90's 9.4 gr per in

i have 150 gr broadheads. how much weight for inserts??

does anyone shoot these arrows?

[BobW]

Do a search for Stu Miller's Dynamic Spine Calculator here in PowWow, download it (need Excel or open Office "Calc" to run it as it is a worksheet), play around a bit, and you will get a good as any starting point.

BobW

[rolltidehunter]

this is all new to me so i do not understand the chart completely.

[Paul Mattson]

What is your draw length?

What length are your arrows?

Type of bow longbow or recurve?

The 250's are going to be stiff but, the 150's should be flying good, depending on the length.

[freefeet]

Originally posted by rolltidehunter:
heritage 250's and 150's are two stiff,

Just keep adding weight up front till they aren't.    

[metsastaja]

you can get the calculator here   http://www.heilakka.com/stumiller/  
I would suggest not using open office on the most recent version.. seems to do something strange..also does not work on mac

I would also suggest you read

http://www.bowmaker.net/index2.htm

[BobW]

Originally posted by metsastaja:
 
I would suggest not using open office on the most recent version.. seems to do something strange..

Like what?  I don't seem to have problems.

[metsastaja]

Bob Since I travel with a Mac laptop
I was testing the spine calculator for Stu on a mac comparing the different versions.  Because of changes in the new Windows office program his 8.9 version calculator stopped running my Mac office. I think it has something to do with metadata conversion. With open office on the mac ver 8.9 I started getting dynamic spines up to 20 higher using the same input.   Version 6-12-09 continues to work fine on my mac.


I have tuned 5 bows using the 6-12-calculator with great success and highly recommend the calculator for getting in the ballpark fast. If not right on then I begin tweaking using OL Adcock tutorial.

[BobW]

Okay, seems a Mac problem only.  Using it with Open Office on a Windows based PC has not been a problem for me.

Thanks for the clarification.

BobW

[rolltidehunter]

53 lbs @ 26 1/2 inches

black widow psa recurve

28 inch arrows.
150 gr broadhead

how do you pull the inserts out to add weight?

[freefeet]

What i did was get some 50gr and 100gr brass shaft inserts.  Started with the 50's and used a little hot melt glue to hold them in.  As soon as they're in the shaft dunk it in cold water to cool the insert as you don't want it heating your shaft up.

If you want the inserts out to put 100's in, screw a field point in and heat that until the insert loosens.  The field point will transfer just enough heat to the insert to loosen it.

When you've got the insert in the shaft, get a load of different weight field points and start bareshafting with them until you find the right weight.  For example...  100gr insert with 225gr field point.

Once you've got that, get a broadhead of that weight.  So for 225gr you can take a 125gr glue on Woodsman and glue it onto a 100gr adaptor and screw that into your 100gr insert.

Hope that helps.

Stan

 

[metsastaja]

Bob out of cuiosity I just ran numbers on my Windows using excel and open office and they came out different.  Could you run the following in your open office and post what you get for dynamic spine.  

I used the 8-09 version


Arrow CE250
BOP 30.5
Nock 11
Feathers
Tip weight 175

Bow type recurve
Rated weight 49
rated draw 28
Draw 30
Center cut 0
string Fast Flight

[metsastaja]

If you don't want to deal with the hot glue. I have been successful using saran wrap around the inserts for testing.