Hey guys getting ready to start tillering my first bow or at least brace it.
Question: do you glass builders start tilling with a long tillering string or do you go straight for you AMO string length? I know wood bow users start long and work to the shorter string but I wasn't sure about the glass guys or even how much you guys tiller a glass bow. If you have your 1/8"-1/4" positive tiller do you go any further down the tillering line if you will.
I've only done two bows but I went to the regular string length right away and with good advice on the stack and the correct shape of the limbs very little tillering was needed. I pretty much sanded to the lines and finish sanded it and it was right there.
What Ranger44 said.
I get the whole bow shaped pretty good, except leave the outer limbs a little wide to allow for alignment adjustments. Then I go straight to the proper length string, brace it, and put it on the tillering tree(rope and pulley system) to see how the limbs are balanced in relation to each other and my grips on bow and string. I draw the bow on the tree, and if one limb needs weakened so that the nock point tracks straight down, I weaken it as needed by narrowing the width. If it starts to get too narrow, I may trap it more and/or sand the glass... but if it was designed and layed up proper, with accurate lams, it shouldn't need much help.
Like with wooden bows, I work to synchronize the limbs, relative to my holds on bow and string, so that the arrow nock comes perfectly straight back... and leaves straight away... and when I get it as good as I can the tiller measurements at brace are whatever they are. They are an end result of my efforts... not a predetermined guide or goal. It makes for an inherently tuned bow that won't require fussing with nock point adjustments.
In a nutshell, I shape the bow, then go straight to the short string... then directly to the tillering tree.
I have a template for the limb profile, after the limb is shaped I cut the string groves and put a string of the right length to get the brace I want. If the bow is built right (on a straight form) there is very little or no work required for tillering a glass bow.
James