Bow mass and mass principle issues

[joachimM]

Hi all,

I'm tillering a mollegabet-like bow stave from the thickest branch/stem of Littleleaf mock orange (Philadelphus microphyllus), aka Syringa, I could find. It's denser wood than what I'm used to.

Stave specs: 153 cm - 60.5", 1" setback, 3.7 cm / 1.5" wide. 25 cm / 10" stiff handle. Tips currently 8 mm wide, levers 23 cm long.
Target bow mass (50#, 27") is around 570 g, but I'm currently already down to 533 g, tillered to 50# at 20" (short string now).

Now of course, handle mass is the big unknown in this equation. If I use a stiff handle of only 7" (there might be a tiny bit of bending in the inner 2" of each limb near the fades), target mass is 506 g. I'm rather on track for that.

I'll brace her in a few scrapes.

Given that I'm very close to target mass already, should I lower my target draw weight?

thanks for your thoughts,
Joachim

[Badger]

    If the bow is not taking set I would keep on going, the suggested mass is not so much science as a rule of thumb to go by. Also the handle style makes a considerable difference. The stiff handle and fade is based on a bulbous osage style handle. As long as the bow is not taking set that should override everything else.

[Stick Bender]

Interesting thread, at your tips being only 8 mm wide I'm not sure if that's for the whole lever length & not knowing the thickness but it sounds like you lost a lot of mass in the leavers that being a good thing I have found that with Steve's chart in TBB that these leaver bows come in a little lighter mass wise then what was published , every body does it different but I try to get the mass in the ball park & save the leavers for last to shed mass , you could use Badgers no set tiller method if you wanted to ,take some of the guess work out a method he uses to keep a eye on set good luck keep us posted

[Badger]

   I do as Stickbender mentioned, if I start falling too low in mass I get very vigilant about the set and try to respond quickly to it by either finding more bending limb or lowering my expectations.

[bradsmith2010]

nice