Stack help

[bowhntineverythingnh03743]

Well guys I am at a loss on how to calculate a stack for a bow. I want to build a new Hill bow soon and am looking to calculate the stack.

I plan on using .050 glass
.030 parallel yew veneers
bamboo core wood

The bow will be roughly a 66 nock to nock and shooting for 45-50# @ 28"

I know that I am going to use some sort of .002 taper I believe in the stack.

Most all of my Hill bows have had four layers of core wood in them.

Can anyone help me out with calculating this please??

Thanks,
Justin

[bjansen]

Have you tried using the lam stack calculator?..if you have made some previous hill bows you should be able to calculate it pretty close.  

Otherwise tell me the stack and poundage you obtained from your last hill and I can tell you the stack to use for a 45-50# bow.

[bowhntineverythingnh03743]

Thanks brad I will attempt to look for that information... I've tried to look at the lam calculator but it throws me over to a file dropper website and I can't go any further.

[bjansen]

Yeah, for some reason that link does not work any more...send me and email and I will send it to you that way.

[monterey]

Justin, not sure if you meant .002 as total thickness taper or more taper utilizing multiple.002 tapers?

if .002 taper total, you will want to keep your fades on the wider side especially if planning on wide tips.  Otherwise you will be overworking the inner limbs and forcing them to propel an unnecessary amount of the mass of the outer limbs.

[bowhntineverythingnh03743]

Monterey I have a total taper of .005 in the entire limb. I never know how thick the lams need to be wtih the bow either. My supplier wanted all of that information as well. I informed him that I am not that great at this sort of calculations. I have been very gifted when Kenny was in business because I tell him a weight and he would send the materials. I will now be keeping extra good records of the bows I make so that I know what they are.

[monterey]

I see.  You will build a true "Hill" style.  If you have any specs' on you previous builds, I can do some calcs for you to consider.

[bowhntineverythingnh03743]

I don't unfortunately this is my dilema.

[kennym]

Justin,

I have a bow in my notes (can't remember who built it)that is

66"

13" riser,

44#@28"

1.25" wide at fades

taper rate at .006PI

Stack - .480"

[kennym]

If you built at .005 PI with same stack , it would come in a bit heavier...

Sorry , don't have glass thickness, but suspect .050 glass at that stack...

Glass is included in thickness so you need .380 worth of lams.

[gene atkinson]

bp has a chart on there web sight that you can go to.

[bowhntineverythingnh03743]

Kenny how do you figure out the thickness if the lams? Do you divide it by the total numbers?

Example

.475 stack
.100 for glass
.060 for veneers

Left over you have .315 so if I'm using 2 .002 tapers and one .001 each would have a butt thickness of .105 and then two have the .002 and one has .001 taper

Am I understanding this correctly?

[kennym]

Yep, you can do it that way, or make a pair a bit thinner, say .080 and run those up belly because they will bend easier.....

The other 2 pair can be .118 then.

Disclaimer - I'm not a Hill guy , so you folks that build them please speak right up!!    :D  

Thx,
k