I have no idea. I thought that the 'limb twist' may have made them a bit stiffer. I checked my tiller - it had increased from 6mm to 8mm (no tiller bolt adjustments made)! However. I sent a copy of my testing to the developer. He sent me a very nice email reply and I believe he is going to 'edit' his manual. He is also sending me another pair of tuning forks in appreciation. I wonder if this has been a bit of a problem all along?
OOPs: I just double checked my settings it should have bee 75 > 70 (not 80 as I mistakenly wrote).
EDIT: I just received this reply.
"Thanks, much appreciated.
Just to touch on some of the points from the email and the thread:
Your case is the first time difficulty has been brought up, and it's very much appreciated. My goal is to make Tuning Forks as user-friendly as possible (alignment/tuning is hard enough), but the process is dependent on the user. Abilities differ. Some eye-ball it, some use a camera.
Often when I'm using them, holding the bow by the riser at arm's length down by my waist is usually good enough (bow is steady, easy enough to shift eye gaze). If I've had too many coffees, I might rest the riser on a table.
I've seen people forget to keep one eye closed, which can cause issues. It's a simple problem, but an easy fix.
I'll be evaluating your method to see if there's a simplification that I could incorporate into the directions to make it easier for users. I always intended this to be an evolving process, which is why I put a version number and a change list in the manual.
At the very least, you can always do a quick sanity-check to see how your alignment is doing by looking at only one Tuning Fork at a time (move head/eye position so that the string covers the bottom indicator, it
should be in line with the top indicator, if it's not there's an issue somewhere). The two Forks are needed for cross-alignment/twist check (adjusting alignment to only one Tuning Fork at a time can cause a circular adjustment loop or each could be in alignment individually but not together).
As for the sight mark/tiller change: there could be a number of factors at play here. The twist of the limbs changes the geometry of the limb/energy stored (tips further out, more potential energy needed to bend and twist limb), the bottom limb could be arriving at brace earlier than the top (nock arrive lower requiring tiller/nock change)... if you shim there could be a slight tiller change from the original setting (though not by much). I think you'd have to chrono the arrows pre and post to see if it's due to increased energy or a change in bow tune. I suspect it wouldn't be due to a faster arrow but I'd be curious at the results.
Again, thanks for your feedback and your help with the account setup.
(Feel free to post the above in the forum if you'd like)
Keith"