A Study in Handshock - Please Help

[John Scifres]

I am working on an osage orange selfbow.  It has a lot of handshock so I thought I'd document my efforts to reduce that.  Along the way I shot video comparing the selfbow that is under construction along with a sweet shooting R/D Longbow I recently acquired.  It'll be fun to see what I can do to tame this beast.  Let me know what you think I should do.

[Buemaker]

Are both bows fitted with a string made from the same material?

[John Scifres]

No the selfbow is B-50 and the glass bow is something a bit less stretchy.  I am sure that is one of my issues but I don't have any fastflight etc.

[Longcruise]

Are you getting hand shock with the self bow?

[John Scifres]

Yes.

[Longcruise]

I  can see it happening but don't have an answer.  The limbs are wigglingike a snake when the string slams home.  They don't seem to be wiggling in unison so that might be a clue.

Following with interest 👍

[kennym]

The reflex helps, and if the nocks are at least an inch ahead of bow back is my pref. This stops the string because of more preload, so there is more tension when it slams home and less limb movement.

Kirk has some pretty good ideas on this, maybe he will be along to comment.

[Noah70]

I watched it about a half dozen times, and I would swear the top nock hits home before the lower, and that’s what’s causing the wobble, which would translate into the shock? IMO.

[John Scifres]

Yes, it does. Thoughts on correcting that?

[Bowjunkie]

John, how did you tiller/time the selfbow's limbs? If you didn't judge the limb strengths on the tillering tree relative to one another while pulling the string from your string hand fulcrum point, it could be a tiller issue. 'Tiller' meaning, dynamic balance at full draw... not what it measures at brace.

[Bowjunkie]

Quick way to find out if its a tiller/timing issue... put it on the tillering tree, draw it from precisely where your middle finger will be if you shoot with three fingers. If the hook comes straight down, limbs are balanced. If the hook drifts toward one limb, that limb is stronger... that is to say, stronger relative to the other limb and your grip on the string.

Make sure the bow handle is level, and draw a vertical 'plumb' line on the wall in the appropriate place to mimic perfect fulcrum travel when limbs are balanced. It makes it easy to see when the hook drifts, because it drifts away from the line. I hope this makes sense. I can post some pictures when I get home if it would help.

[Mad Max]

You can try holding you bow lower and lower on the grip and see how it shoots. Or even upside down
Selfbows are negative tiller with Symmetrical limbs

[Mad Max]

SORRY---I disagree on the handle of a SELFBOW being level, this bow grip angles up on the right side, I set it up with limb tips level unbraced.

[Bowjunkie]

Mad Max, I've done that too on bows with wonky character in the handle area. They can still be dynamically balanced that way.

Each bow can be different and it's a judgement call sometimes. But in general I try to shape and adjust the handle area so that the tillering tree cradle is holding it the way I want to hold the bow, any bow, and how I want the drawn balanced bow to evenly force the handle area straight back into the hand. When it does come straight back, I don't want it to feel like it's tilted/tipping... if it can be avoided.

I don't concern myself much with leveling the tips though because, depending on natural shape irregularities of the limbs, the tips might not be equadistant in front of the handle area, or much of the balance of the limbs for that matter, and it's not necessary for the tips to be 'level' in order for the limbs to be dynamically balanced anyway.

[simk]

My guess also was a tillering issue . Hard to say from the vid tough - it's not the best angle in the vid to judge tiller and the unbraced profile is missing too. Could be that top limb somehow is a little stiff and heavy mid and outers? Do you have a positive tiller? Just guessing....
cheers

[John Scifres]

I have followed Torges' instructions from "Tillering the Organic Bow" (http://bowyersedge.com/organic.html) as much as possible since I read it, what, over a decade ago?  Almost certainly more.  If I had regrets, one of them would be when Dean and I were talking about it at Cloverdale and I told him I had to read it 3 times to start to understand.  I think he took at as slight to his writing when it was actually an admission of my own dullness

But I am wiping clean what I thought I knew; so let's start again.  Bowsite's ***********, TradGang and the community that resulted taught me then and can teach me again. 

I will post a video later today or maybe tomorrow of where the bow currently sits and we can work on it together.  Thanks for the input.

[John Scifres]

For more context, go to the Swap Bow thread pinned at the top or visit my YouTube Channel https://www.youtube.com/channel/UCd1zciLMYHIsFEKSqERkJAw

Thanks again my friends.

[Mad Max]

I don't concern myself much with leveling the tips though because, depending on natural shape irregularities of the limbs, the tips might not be equadistant in front of the handle area, or much of the balance of the limbs for that matter, and it's not necessary for the tips to be 'level' in order for the limbs to be dynamically balanced anyway.

On this bow leveling the handle would have made left limb 4" above the right.
I was at the TN. Classic years ago and I had a stave with the same whoop de doo at the handle and I kept saying but the handle goes up from the limbs and I was told "your tillering the limbs, the handle has nothing to do with it"

[John Scifres]

A few more bow details:

65" NTN
Osage Selfbow
Even Limbs
Fulcrum 1" above center
Pulling string with hook at middle finger
Split finger draw
51" @ 28"

I shot the bow with 555 grain arrows and it felt better but still pretty shocky.  I think my nocks are too tight on the string as they won't pop off with a tap.  Sorry, no video of the shooting.  Too dark.  The song, ironically, is titled "Equilibrium".  Comment appreciated.

[Mad Max]

How wide are your tips before the string groves John ??