Author Topic: another limb stack questionUPDATE (Read 439 times)

scottm · « **on:** February 10, 2013, 10:16:00 PM »

I built my first set of take down recurve limbs for a RMR replica.I followed the bingham chart for there design .255 stack.They came out 10# lighter than i was wanting.Im using bamboo flooring for core lams im wondering if binghams is based on a denser wood like hard maple for cores?I understand stack veries alot by design. So im making another set.I followed binghams chart again but this time add .015 to the stack(.270).im hoping this raises my weight by 10-12#.According to there chart-(there design) .013 should raise wt by ten pounds.Im hoping im figuring the new stack right.what do you all think?

Thanks Scott

kennym · « **Reply #1 on:** February 10, 2013, 10:20:00 PM »

Scott, is the pad angle different?

2* on my TD LB proto, made 7 # difference.

Just a thought...

Dmaxshawn · « **Reply #2 on:** February 10, 2013, 10:31:00 PM »

Scott I have seen a difference between the floor boards that I use sometimes. It's enough to buffle ya. I built two of the same exact bows same everything and they came out 8 pounds different. the only thing different was the floor boards that I used for cores.

scottm · « **Reply #3 on:** February 10, 2013, 11:24:00 PM »

Kenny its a 21 degree pad angle.My first Longbow came out ten pounds light also.Im wondering if its the bamboo flooring compaired to other core woods.After the first long bow i ajusted the stack and the other three came out dead on.One of them was even bamboo from another box i had,a totaly different brand.It still hit right on the weight(i guess i was lucky).Shawn thats what im talking about with stack charts.There great,at lest they'll get you close,but the core wood used must make quite a difference in stack thickness.I guess its like making an BBH compaired to a BBI.Ipe is denser therefore comes out thinner than the hickory to make the same weight.Im just trying to figure out if i addded enough to the stack to make up the ten pounds. difference.Scott

scottm · « **Reply #4 on:** February 11, 2013, 01:07:00 PM »

Well i put a .270 stacked limb in the oven so hopefully well see what weight this one turns out to be.Scott

Robertfishes · « **Reply #5 on:** February 11, 2013, 05:18:00 PM »

my bows were coming out 8-10 lbs heavy..found out my digital caliper was reading aprox .002 off each piece in stack..it would zero out but when i bought a set of feeler gauges I caught the problem.. I should have caught it sooner since all my 040 glass was 037 - 038, I just thought maybe that was in Gordons Glass tolerance range.

scottm · « **Reply #6 on:** February 15, 2013, 12:51:00 AM »

Well the limbs came out 50#@28" which is what i was looking for.Now at least i have a couple of base line numbers to work off of...Get this.I couldent believe what happened.I took the form out of the oven.Every thing looked normal.When i went to pull the LVL form apart.The curved end of the form snapped off horizontaly!Thats like 6" or more of LVL!It just snapped!My form gap was 1.25" 70# of air.Ill have to make a new upper section for the form.No big deal i just cant believe it broke like that

jess stuart · « **Reply #7 on:** February 15, 2013, 02:39:00 PM »

Scott, glad to hear you hit your desired weight. Too bad about the form! Everyone swears by LVL, just one of those things I guess. Get her finished up I want to see some pics.

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