While my question is not directed to the tillering process, I am curious about the position of the mid-limb post in the glue-up of an R/D stave. Specifically, what effect on cast does the mid-limb post have on performance? I believe your mid-limb post is about half way between the center & the end post. What effect on cast/performance should I expect if I moved the mid-post closer to the center post? I suspect it may have something to do with the percentage of working limb, but would hope to understand the mechanics of what I do a little better. Thanks for your thoughts, Tom.
Different Tillering Procedure for Trad, R/R and R/D Staves?
This seems to be a fairly common question from bowyers who have 5-10 bow builds under their belts:
Tom,
I was wondering if I have to handle the reflex reflex and the reflex deflex staves any differently than past Traditional bow builds. Are there any major difference in how I need to handle the different staves. Thank you again. I look forward to making more- and better- bows all the time.
At the risk of simplifying the tillering process of R/R and R/D staves too much, the main differences between tillering those two styles and compared to tillering traditional limb staves (into bows) is that you must be a bit more careful in removing material from the mid limbs.
Imagine "teaching" a backward bending piece of wood to arc correctly and gracefully in the opposite direction.
The first 4 steps in my version of bow building- floor tillering the stave, filing to the profile lines, beveling the bamboo backing and removing wood from the sidelines to the center line is pretty much the same as when you are building bows from trad or slightly reflexed staves.
The difference becomes very apparent once you are able to string the stave. The curve you might be expecting to see looks more like the sharp angle of a gull's wing!
Look closely at removing material from approx. 6" from the tips to approx. 4" above and below the riser areas.
Take it slow, keeping in mind that a little goes a long way when building bows from staves possessing extreme levels of tension.
Tom,
I was wondering if I have to handle the reflex reflex and the reflex deflex staves any differently than past Traditional bow builds. Are there any major difference in how I need to handle the different staves. Thank you again. I look forward to making more- and better- bows all the time.
At the risk of simplifying the tillering process of R/R and R/D staves too much, the main differences between tillering those two styles and compared to tillering traditional limb staves (into bows) is that you must be a bit more careful in removing material from the mid limbs.
Imagine "teaching" a backward bending piece of wood to arc correctly and gracefully in the opposite direction.
The first 4 steps in my version of bow building- floor tillering the stave, filing to the profile lines, beveling the bamboo backing and removing wood from the sidelines to the center line is pretty much the same as when you are building bows from trad or slightly reflexed staves.
The difference becomes very apparent once you are able to string the stave. The curve you might be expecting to see looks more like the sharp angle of a gull's wing!
Look closely at removing material from approx. 6" from the tips to approx. 4" above and below the riser areas.
Take it slow, keeping in mind that a little goes a long way when building bows from staves possessing extreme levels of tension.
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Yakoke,
I do not profess to know all of the physics involved in the moving limbs of a bow, however, I do know what I like to feel in the moving limbs of a bow!
I approached the mid-limb block placement much like I do when I reload long distance rifle ammunition.... except in inches and not thousands! For me, moving the mid-limb blocks in increments of 2" was similar to "seating" a bullet in or out of a case mouth to find the sweetest spot.
Not too long ago, ahem
I experimented with moving the mid-limb blocks of a R/D jig in 2" increments from (Position 1.) 8" off the center block all the way out to (Position 10.) 28" off the center block.
My findings were relatively obvious.... in hindsight that is.
Staves from all 10 mid-limb block variations produced "shooting" bows. As one might expect there were desirable as well as undesirable characteristics in some. For example the bow with blocks placed in Position 1 resulted in a bow with a "sweepy" action. At the other end of the experiment, the bow built with blocks placed in Position 10 felt more "whippy".
Initially I found a sweet spot right around the 16"-18" position. After additional experimenting and fine tuning I found the sweetest spot for 72" Reflex/Deflex bows tended to be at the 17.5" mid limb mark.
Because of these findings all of my personal hunting bows, my customer custom bows or my Advanced Class students' bows are built from staves with the mid limb blocks set at 17.5".
In my opinion....
Bows built correctly from 72" bamboo backed, Reflex/Deflex staves are hand shock free, provide the sweetest shooting and smoothest action in any bend-through-the-handle bow!
You can take my word for it, my students' & customers' word for it or better still build a few of your own and you'll know for sure!
I do not profess to know all of the physics involved in the moving limbs of a bow, however, I do know what I like to feel in the moving limbs of a bow!
I approached the mid-limb block placement much like I do when I reload long distance rifle ammunition.... except in inches and not thousands! For me, moving the mid-limb blocks in increments of 2" was similar to "seating" a bullet in or out of a case mouth to find the sweetest spot.
Not too long ago, ahem
I experimented with moving the mid-limb blocks of a R/D jig in 2" increments from (Position 1.) 8" off the center block all the way out to (Position 10.) 28" off the center block.My findings were relatively obvious.... in hindsight that is.
Staves from all 10 mid-limb block variations produced "shooting" bows. As one might expect there were desirable as well as undesirable characteristics in some. For example the bow with blocks placed in Position 1 resulted in a bow with a "sweepy" action. At the other end of the experiment, the bow built with blocks placed in Position 10 felt more "whippy".
Initially I found a sweet spot right around the 16"-18" position. After additional experimenting and fine tuning I found the sweetest spot for 72" Reflex/Deflex bows tended to be at the 17.5" mid limb mark.
Because of these findings all of my personal hunting bows, my customer custom bows or my Advanced Class students' bows are built from staves with the mid limb blocks set at 17.5".
In my opinion....
Bows built correctly from 72" bamboo backed, Reflex/Deflex staves are hand shock free, provide the sweetest shooting and smoothest action in any bend-through-the-handle bow!
You can take my word for it, my students' & customers' word for it or better still build a few of your own and you'll know for sure!
1 - 3 of 3 Posts
