AMO weight

[Radmcg]

Is the 28" AMO weight standard the actual measurement to the pivot point/deepest part of the grip or the above plus 1.75 inches (the way draw length is measured)?  In other words if I put my bow on my weight/tiller jig that measures from the deepest part of the grip.  Should I pull it back to 28" from that spot or 26.25" from that spot to measure draw weight? My wall board is measured from the deepest part of the grip.

[Crooked Stic]

I always measure from the string to the front of the bow.

[Mad Max]

It's to the deep part of the grip + 1-3/4"

[Radmcg]

So if I want to know what my poundage is at 28".  I pull the string back to 26.25" from the deepest part of the grip?

[Mad Max]

So if I want to know what my poundage is at 28".  I pull the string back to 26.25" from the deepest part of the grip?

Yes

[Kirkll]

So if I want to know what my poundage is at 28".  I pull the string back to 26.25" from the deepest part of the grip?

Most people just measure from the back of the riser, which really is the front of the riser, but it's facing  away from you so you are looking at the belly side when shooting it.... You get that ok? 

There are some simple ways to measure it solo without having it on a tiller tree, or having someone else mark the arrow at the back of the shelf. A clothes pin works well. Just clip it on the arrow and it will stop at the shelf and slide out to your draw length. A plastic hair clip will work too, or even a piece of cardboard board with a hole in it works.

[Radmcg]

Yeah Kirk I got the AMO draw length part.  I was trying to confirm the AMO draw weight measurement.  I'm trying to see where the bows I built actually are in weight so I can predict weight from that lamination stack or at least estimate.  For some reason my TD recurve limbs finished come out 5 lbs low and my longbows come out of 7 pounds high compared to my predictions.  Different stacks of course.  Just trying to make sure I was measuring from the correct place every time.  I like the cloths pin part seems a little better than the playing or index card.  I'm going to try that when I get home.
Thanks for the help.

[Kirkll]

Yeah Kirk I got the AMO draw length part.  I was trying to confirm the AMO draw weight measurement.  I'm trying to see where the bows I built actually are in weight so I can predict weight from that lamination stack or at least estimate.  For some reason my TD recurve limbs finished come out 5 lbs low and my longbows come out of 7 pounds high compared to my predictions.  Different stacks of course.  Just trying to make sure I was measuring from the correct place every time.  I like the cloths pin part seems a little better than the playing or index card.  I'm going to try that when I get home.
Thanks for the help.

The atual AMO 1.75" grip depth can change depending on the grip design, but typically not much more than 1/4" at most. Most grips have a circumference of 4.75" to 5 1/8" , and vary on width, or thickness of the throat.  I've have seen some Hill style straight grips as much as 2.25" depth. So measuring the 26.25" to the deepest part of the grip will keep you consistent.

As far as hitting draw weight consistently goes, there are a lot of factors that can change things from one bow to the next. Your fiberglass alone can change things up 5 pounds easily. its best to buy it in as large of quantities as possible.  If you buy it just a few sticks here and there, you can get a strength difference from one batch to the next. So your first lay up is always a crap shoot. clear glass is typically a little lighter than black glass for some reason too. How many core lams and thickness can change things too, but typically not much...Good rule of thumb is never go over .080 thickness in your lams in the working portion of the limbs. Good example would be this... lets say we have a .300 stack height with 40/40 glass. that leaves 220 for a core. you are much better off milling 3 lams between .065-.075 to get your .300 stack than 2 lams at 110.  I always measure my stack at 10" up from the limb butts too. This is much more consistent than just measuring the butts.

Other things that can alter draw weight is type of core lams, and type of wedge material. Both tip wedges and butt wedges.  If you make notes in your bowyers log for all these things and log the exact rough in weight you get with each different type of material, a pattern will emerge . Also it helps to use a pattern for your limb profile and always rough them out for test weight a wee bit wide. This can save you on ones that are close to dead on, but would be too low at std width. This is especially true with deep core long bows. RC not so much due to shorter stack heights.

I like coming in rough weight at 5# -7# over target weight. Makes it easy to adjust tiller and finish sand without worrying about dipping below target weight. You can always sand a bit of glass, but its not easy to put weight back on. Customers will typically handle a couple pounds heavier than specs, but nobody is happy if you drop below target. or rarely i should say.

The every now ad then you get your W.T.F. bow that just mysteriously comes in 15-20# heavy for no good reason at all.   I just had that happen this week and had to go again and lay up new limbs..... Hope this helps....  Kirk

[Radmcg]

Thanks Kirk on a different note.  Since you mentioned ordering in bulk. I ordered some Bow Tuff a few months back.  It came rolled up.  Do I need to unroll it for medium term storage or is it ok to leave rolled up?

[Kirkll]

Thanks Kirk on a different note.  Since you mentioned ordering in bulk. I ordered some Bow Tuff a few months back.  It came rolled up.  Do I need to unroll it for medium term storage or is it ok to leave rolled up?

I unroll mine as soon as it arrives and store it flat... Just be carefull cutting the tape or you can get b itch slapped pretty hard...

[Crooked Stic]

So that's what is wrong with you Kirk 

[Kirkll]

guilty as charged...