Hand Shock

[Jaenak]

This is going to sound like a *DUH* kind of question but bear with me because that's not how I mean it.

What causes hand shock?  There's the *DUH* part.  I know that it's caused by vibrations in the bow that are generated when you release the string.  What I want to know is if that's the only contributing factor to hand shock and what can a bowyer do while making the bow to reduce hand shock as much as possible.  I guess you could also say, why do some bows have more hand shock than others?

I know that the heavier the arrow the more shock it'll absorb, the lower the brace height, the longer the string will be in contact with the arrow and thus the more shock it'll be able to transfer to the arrow, and I know that some types of wood absorb more shock than others although I really don't understand that last one.  I also suppose that the more wood there is in the bow itself, the more shock it'll be able to absorb.  Any thoughts, comments, ideas, etc?

[Apex Predator]

Hand shock is caused by improper limb timing, and excessive weight at the tips.  Design also plays a part.

[Pat B]

Hand shock is excess energy that is not absorbed by the arrow. Like Apex said it can be because of improper limb timing or excess weight in the outer limb tips or just poor bow design or even a heavy string. Depending on the bow and its design, most hand shock can be eliminated or reduced to an almost unnoticeable level. Having a heavy riser can "absorb" the extra vibrations that cause hand shock.
   Are you talking about a glass bow or a wood bow? I build wood bow so I can maybe help reduce hand shock with a self bow or wood bow. Others can give you better advise for glass bows.     Pat

[ChristopherO]

My Martin #10 Pioneer longbow is a reflex only designed bow (the limb are straight but are angled out past the back of the bow a bit).  If gripped too tight it jots my bow forearm and hand so that my watch can cause a sore on my wrist in just a shooting session.  I've learnt how to hold it better now but still there is handshock.  
I've had the opportunity, once, to try out a R/D fiberglass bow and was stunned by the amount of handshock: NONE.  I've lately put together a few BBO trilams of the R/D persuassion and am impressed with their softness in the hand.  Same is said of my Dad's 1960 vintage Herter's recurve:  Smooth as silk and no shock.
As said above design coupled with other elements makes or deletes handshock.

[Jaenak]

*wips out notepad*
riser too light...string too heavy...bad limb timing...too much weight at the limb tips

So, a heavy(ish) riser, a heavy arrow, low brace height, light and relatively skinny limb tips, a thin string, a thick leather grip, and great limb timing will help to reduce hand shock.  Cool.  All except that last one, could anyone explain the limb timing to me?  Also, how do you change the limb timing when making a bow?  I've always had this childish notion that both limbs always magically straighten at the same time with the same speed.  And yes you're right, I've obviously never made a bow.  I'd like to one of these days though.  A wooden one that is, no fiberglass.

[Glenn Newell]

All of the above are good suggestions. Hand shock can be eliminated in most bows just by correcting bad limb timing. I see a lot of bows where the tiller is no where near right but people keep insisting on using the same bad formula to tiller their bows. A whip tillered bow can have hand shock or at least excessive vibration when shot. The heavy strings dont help either....Glenn...

[ChristopherO]

"I've always had this childish notion that both limbs always magically straighten at the same time with the same speed."

If one limb is too stiff and the other is too weak they won't time up right.  When tillering a bow you look for the limb tips, at least I do, to be pulled the same distance.  I mark horizonal lines on the wall behind the tiller tree.  Then I stand back and pull the cord attached to the bow string to see if the limbs are arching correctly and if the tips are both touching the same line on the wall.  If one is an inch off then you will know that those tips aren't timed up.  Admittedly, I am still a neophite at wood bow building but this is what I've learned from my studies on the subject.  Seems to work for me when I get it right, too.  
Hope it helps.
By the way, light risers don't have to have handshock if the bow is tillered and designed well.  I've shot bows that don't have massive risers that are extremely smooth.  The R/D fiberglass I mentioned above is like that.  Striker Bows, also, are very smooth, yet, with a petite riser.

[Pat B]

Christopher is correct except for one thing; the limbs have to bend evenly and together. Just because the tips pull the same distance doesn't mean the limbs bend evenly. You could have a hinge or stiff spots that would prevent an even bend in the limbs even though the tips line up.
   A heavy riser doesn't make it a given either. On my self bows I use a bulbous handle and the limbs usually bend right up to the handle. My handles are very light and my bows have little hand shock. In many cases with self and wood bows tip weight is the culprit. Pat

[Jaenak]

Cool.  So if both limbs bend the same distances in all the same spots all the way up and down the limbs, then they'll be timed correctly?  Sounds like it'd be a good idea to draw a one inch square grid on the wall behind the tiller tree so you can measure every spot all the way up and down both limbs.

Thanks everybody!

[Pat B]

If you make a symmetrical bow both limbs will bend the same and together but if you build an asymmetrical bow both limbs will bend together but not the same. One limb(usually the bottom) is shorter so its bend will look different than the longer one.  This is one reason I prefer a symmetrical design...for ease of tillering for me.
   Don't let all of this confuse you. Just do it. Lots of what we are talking about will become second nature to you and you will hardly have to think about it. You just have to develop an eye and a feel for it.     Pat

[Glenn Newell]

If you make a symmetrical bow and shoot the arrow 1.25 inches above centre on the riser and the riser is equal length either side of centre the string to the top limb will be 2.5 inches shorter to the top limb than to the bottom limb from where the aarrow is nocked. You will be placing more pressure on the top limb which will make it bend different to the bottom limb. If you make the top limb weaker than the bottom limb you will make it bend a lot more than the bottom limb, the bow limbs will be automatically way out of time with each other and have a lot of hand shock...Glenn...

[Art B]

If you make a symmetrical bow and shoot the arrow 1.25 inches above centre on the riser and the riser is equal length either side of centre the string to the top limb will be 2.5 inches shorter to the top limb than to the bottom limb from where the aarrow is nocked. You will be placing more pressure on the top limb which will make it bend different to the bottom limb. If you make the top limb weaker than the bottom limb you will make it bend a lot more than the bottom limb, the bow limbs will be automatically way out of time with each other and have a lot of hand shock...Glenn...

Using what type of grip Glenn? Yes, if you use a straight wrist/low contact type grip then you will apply greater pressure to the top limb. Apply a full hand/low wrist contact and you'll put greater pressure on the lower limb. Apply proper grip to the 1.25 inches above center and both limbs feel even strain. Folks kind of forget or simply don't know that you've got to grip a bow according to its design.-ART B

[Pat B]

...just because it's simple doesn't mean it is easy!

[ChristopherO]

Hey Pat,
I believe I was correct in everything I said.  I just shortened what you said,
"the limbs have to bend evenly and together. Just because the tips pull the same distance doesn't mean the limbs bend evenly. You could have a hinge or stiff spots that would prevent an even bend in the limbs even though the tips line up."
down to,
"Then I stand back and pull the cord attached to the bow string to see if the limbs are arching correctly".  
You just added the right amount of words to make sense!
Jaenak, Pat is right, you will have to dive in and do it to see what we mean.  I am still learning by doing and reading these men who have the knowledge.

[Pat B]

when we quit learning we had better just give it all up!      Pat

[ber643]

That's a great point, Art B, my friend (good to "see/hear" you), and one I would dearly love to see some difinitive pictures or diagrams of someday. I tend to think that I use pretty much the same grip all the time but I know that's probably not compleatly so. I probably, in fact, adjust my grip to the bow I am shooting (within my parameters) to were it is the most comfortable with that particular bow, and it shoots the best for me - subconciously (or maybe unconsciously is more like it - LOL). In truth, I'd have to admit that probably someone like you, or other friends who have watched me, or seen pics of me, know more about the type of grip(s) I use than I do.

[Glenn Newell]

Art B that is true what you say, I made a real nice short selfbow years ago and I let someone shoot it but he shot the bow with his thumb pointing up towards the top limb and pulled the bottom limb way out of shape, it needed to be a lot stiffer for his hand grip and style.
I still had in my mind what had been said on other post here about tiller. I know that there is no one formula to cover tiller on all bows as bows come with equal length and unequal length limbs and tiller always has to be adjusted to suit hand placement on the bow and string and as you have correctly pointed out high and low wrist grips. Selfbows are a dead give away and quickly show up any tillering mistakes...Glenn...

[Art B]

Hi Bernie, always a pleasure to look/listen in on your conversations (mostly a lurker these days you know)! From looking at your pose over on your Holmi thread it looks like you and I have pretty much the same grip (low to medium). For myself (and most of my friends) I go 1 1/2" above center for this type of grip. That's about average for most folks from what I've gathered over the   years. For the real punishers like my son I will raise that to 1 3/4" to 2". He's got a big ol' hand and uses it all on the handle. Even for myself I'll raise my arrow pass to 1 3/4" to compensate for higher weight bows (I tend to need more hand to handle the extra weight).

But it all comes down to making a few bows and then deciding what works best for yourself. Nothing really set in stone here.

Glenn, I'm still crying over that very nice bent eared hickory static I gave my son last year. ART B

[Glenn Newell]

Art, I have a couple of selfbows now that I never string up if someone wants to handle one, some people just don't know how to handle selfbows properly. Hand placement on the bow makes a huge differance to how the limbs will bend when being drawn...Glenn...

[ber643]

Thanks, Art, glad you looked in there - I just wish I knew one tenth of what you know about wood bows (and arrows) - and, while I'm at it, then I wish I could retain just one tenth of that -    :D   . I sure do have fun though ("with a lot of help from my friends"       ).