« previous next »
Pages: [1]

Author Topic: String lift off  (Read 2949 times)

0 Members and 2 Guests are viewing this topic.

Offline DC

  • Member
  • Posts: 10,396
String lift off
« on: February 19, 2016, 02:47:03 pm »
I'm tillering a boo-yew recurve and I noticed that one limb lifts off before the other. One is at 11" and the other is about 13". Is this something to be concerned about? It's room temperature cured epoxy and I glued in some Perry reflex so I'd rather not heat it. I'm pulling it 17"@40# right now I'm shooting for 45#@28".
Thanks
Logged

Offline PatM

  • Member
  • Posts: 6,737
Re: String lift off
« Reply #1 on: February 19, 2016, 02:58:08 pm »
That's part of tillering and  "timing" and whether you notice it personally in the shooting characteristics of the bow.
Logged

Offline DC

  • Member
  • Posts: 10,396
Re: String lift off
« Reply #2 on: February 19, 2016, 03:02:40 pm »
I don't want to open the timing debate again but how would that manifest itself? Hand shock or????
Logged

Offline bow101

  • Member
  • Posts: 2,235
Re: String lift off
« Reply #3 on: February 19, 2016, 03:27:32 pm »
Only time I ever got hand shock is from overly thick or heavy tips.  Can timing be perfect 2-3 years down the road..? I question this with wood bows.
Logged
"The privilege of a lifetime is being who you are."  Joseph Campbell

Offline Badger

  • Member
  • Posts: 8,124
Re: String lift off
« Reply #4 on: February 19, 2016, 03:46:14 pm »
 When you draw it back your handplacement affects how they lift off. You want them to lay back down evenly when the arrow is being released, your hand will be gone at this point. If it is off you will see the arrow slightly porpoise possibly. You can play with the nocking point and even the height of the arrow rest to tune it.
Logged

Offline bow101

  • Member
  • Posts: 2,235
Re: String lift off
« Reply #5 on: February 19, 2016, 03:50:27 pm »
Quote from: Badger on February 19, 2016, 03:46:14 pm
When you draw it back your handplacement affects how they lift off. You want them to lay back down evenly when the arrow is being released, your hand will be gone at this point. If it is off you will see the arrow slightly porpoise possibly. You can play with the nocking point and even the height of the arrow rest to tune it.
Yep nothing like fine tuning.  Good point about "your hand will be gone at this point"
Logged
"The privilege of a lifetime is being who you are."  Joseph Campbell

Offline DC

  • Member
  • Posts: 10,396
Re: String lift off
« Reply #6 on: February 19, 2016, 03:56:54 pm »
Quote from: Badger on February 19, 2016, 03:46:14 pm
When you draw it back your handplacement affects how they lift off. You want them to lay back down evenly when the arrow is being released, your hand will be gone at this point. If it is off you will see the arrow slightly porpoise possibly. You can play with the nocking point and even the height of the arrow rest to tune it.

So if I move the bow right or left on the tree I should notice a change in lift off?

" If it is off you will see the arrow slightly porpoise possibly."  This is the kind of answer I was looking for. Something I can look for.
Thanks
Logged

Offline bubby

  • Member
  • Posts: 11,054
Re: String lift off
« Reply #7 on: February 19, 2016, 04:18:29 pm »
Dc are you far enough along to start slinging arrows, if so film the release and watch what happens
Logged
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline DC

  • Member
  • Posts: 10,396
Re: String lift off
« Reply #8 on: February 19, 2016, 04:42:15 pm »
Not quite, maybe the rain will let up by the time I'm ready.
Logged

Offline DC

  • Member
  • Posts: 10,396
Re: String lift off
« Reply #9 on: February 19, 2016, 05:05:27 pm »
I went back to the shop and took a close look. I figured that the limb that was lifting last (top limb) must be straighter so I decided to check the +- tiller. I had about 1/2" negative. (I think I said that right.) Anyway, I evened it out so I have neutral tiller. Presto!! String lift off is the same on both limbs. Now, in hindsight, everyone's posts make sense. I'm now at 20"@ 40# so I could fling a few arrows but I would drown out there.  ;D ;D ;D
Logged

Offline bradsmith2010

  • Member
  • Posts: 5,187
Re: String lift off
« Reply #10 on: February 19, 2016, 08:10:55 pm »
I think the same thing happens with a straight tip bow,, we just can't see lift off, but the timing is affected in much the same way,,if the tiller is off,, :)
Logged

Offline simson

  • Member
  • Posts: 2,310
  • stonehill-primitive-bows
    • stonehill-primitive-bows
Re: String lift off
« Reply #11 on: February 20, 2016, 04:01:52 am »
DC control the angle of the hooks/levers, sometimes one let go.
Also control your pivot point, a change here changes the tiller!

Positive tiller - asym. bow
Zero tiller - sym. bow

I make most of my statics asym. with pos. tiller - with matching string lift off.

Don't trust the tiller tree, lot of factors to watch

Just my thoughts ...
Logged
Simon
Bavaria, Germany

Offline Del the cat

  • Member
  • Posts: 8,322
    • Derek Hutchison Native Wood Self Bows
Re: String lift off
« Reply #12 on: February 20, 2016, 04:32:19 am »
Gotta see how it is in the hand.... no one actually shoots off the tiller! >:D
Del
Logged
Health warning, these posts may contain traces of nut.

Offline Springbuck

  • Member
  • Posts: 1,545
Re: String lift off
« Reply #13 on: March 03, 2016, 05:10:12 pm »
  This is one reason I like making recurves with string bridges.  I can tune this just a bit by moving the bridge or making one slightly higher than the other.
Logged
Pages: [1]
« previous next »