Handshock

[Badger]

     I have seen the topic of handshock come up every now and then. I have never really seen a perfect answer as to why some bows have handshock and some don''t. Some bows look like they would be shocky and are not while other bows look like they would not be shocky and are very shocky. Last weekend I shot a bunch of different bows, every one I could get my hands on. The majority had more shock than I like but tolerable while others were miserable to shoot. I spent several hours just watching the bows being shot to see if I could pin point anything worth looking into. You could actually see with the naked eye the center of the limbs bulging forward and vibrating after the shot. Some bows had a slow reverberating heavy type shock while other bows had a sharp quick painful jolt. A couple of the bows were very narrow low mass bows but still had painful handshock. Pyramid bows in general seemed to have less shock. Most all of the r/d bow designs with stiff outer tips were almost shock free. Even some of the bendy handled longbows were shock free. The most obvoius predictable shockers were overbuilt bows with long paralell limbs tapering the last several inches to the tips.
       I still haven't come up with a good answer that covers it but it sure does look to me like limb timing is the biggest culprit right along with unevenly stressed limbs. I took one of my bows that had a sharp painful jolt to it and just narrowed it a bit midlimb, took about 3# off it and got it bending a little more in that area and the shock just disappeared, Anyone else have thoughts on handshock?  Steve

                                                                                                                                                                                                                                                             

[carpenter374]

narrower tips help. string silencers reduce vibration also.

[david w.]

my two bows have very little to no handshock

one is 70" ntn and 1 1/2 at midlimb with the last 15" inches tapering to 3/8 at the tips

the other is 66" and 2" at midlimb with the last 15" tapering to 3/8 at the tips

both these bows are a pleasure to shoot i love them

that gets me thinking i still havent posted pictures of that second bow

[GregB]

Although I typically try to have the last 4-6" to the tips nonbending, I try and keep the mass weight as low as possible in the tips.

[JackCrafty]

Hmmmm....could you explain what you mean by "limb timing"?
As for unevenly stressed limbs adding to handshock...I don't know about that one.  For example, it's been observed that "whip tillering" helps to reduce hand shock....and so does a stiff handle.

I've been shooting like crazy lately to discover what causes hand shock in short bows.  It seems to me that there are two "stages" of hand shock....the 1st stage is at the moment of release and the 2nd stage is when the string snaps tight after the arrow leaves the bow.  The 1st stage messes with your accuracy and the 2nd stage messes with your pain tolerance.   

My bows made of high stiffness wood (like HHB) have 1st stage hand shock and my bows made with low stiffness wood (like Juniper) have 2nd stage hand shock.  My bows made of ipe seem to have BOTH stages of hand shock. 

Overall, a loose grip eliminates hand shock.....which leads me to believe that whatever causes the handle to vibrate is the culprit.  Lighter tips and a heavier grip seem to be the logical cure.

[Badger]

Good point Jack, I think there are actually several culprits. A lot of folks feel harmonics plays into it and it does make sense. The one little bow I had the problem with you really couldnt even feel the shock, just the pain as it was very sharp when it hit, I really don't get many bows that are shocky but I have had a few doosies that always puzzled me. Steve

[Kegan]

Center section mass vs. tip mass. If the center is too light than the mass and energy of the limbs will move the center. Mainly seems to come from the limbs moving more and more forward of the center, hecne either narrow tips or high brace heights.

They had it in an old magazine article on why some longbows (fiberglass laminated) were so much less reliable than modern recurves.

[artcher1]

I agree also that's there's several causes of handshock Steve. Biggest one for me is hand placement and timing. Take for instance you grip a bow designed for a low wrist and then shoot it using a high wrist, or vice verse. Limb mass is now out of sync and you'll experience handshock. Proper grip for proper design is required. But even that isn't enough for proper timing if dimensional center and static balance is out. They should be one and the same.-ART B

[Slivershooter]

I have found that reflexing the tip and keeping the last 4-6 inches non- bending eliminates most of the hand shock.  On extremely snakey bows I do the final tillering by feel rather then sight.  It's kind of hard to explain, but on these bows I can usually determine where the shock is coming from when I shoot them.  Although I don’t use the harmonic theory when tillering, I have found that the bows with the least amount of hand shock have the limbs bending evenly throughout the draw.  i.e...  Both tips when drawn are at the 10”, 12”, 20”, ECT, at the same time throughout the entire draw.

Walt Francis   

[AndrewS]

I agree with Walt.
Evenly bending limbs are a recipt against handshock.

[George Tsoukalas]

There are other more obvious causes like a bow that bends too much in the handle and nocks that are too heavy. Timing is the one that is the least understood.  Limb timing is very important. I can watch the limbs flex and return on my rope and pulley. That will give me somewhat of indication. Later when I go out to shoot the new bow. I pay attention to handle pressure to make sure it is even as I draw and release the arrow. Limb timing and tiller are related but they are not the same. A bow can appear out of tiller, still have good timing and shoot well. Tillering character bows makes a bowyer really aware of timing . Anyway, that's it for now. Here is an example of tiller and timing. Jawge
http://mysite.verizon.net/georgeandjoni/seneca.html

[DanaM]

I've only shot my own bows and truth be told I've never noticed hand shock. When I get to Pappy's I'm
hoping to get a chance to shoot lots of other folks bows for comparison sake. So if any of are going to TOJAM
and ya have a real teeth rattler please bring it, I need to experience it first hand. One thought I have on hand shock is
even when I was shooting compounds I noticed so many people gripping the handle like they were choking a rat
and I believe this also contributes to hand shock. I was taught loose grip not death grip.

[adb]

I notice handshock when I'm shooting light arrows. I have some Goldtip Traditional carbons, and when I shoot them out of most of my bows over 45#, recoil becomes an issue. With the same bow, and hunting weight arrows, handshock is gone. 
I agree, a well tillered bow, with limbs working equally and properly timed, will have less recoil. I also notice more handshock with shorter bows. There is nothing more smooth than a 72-76" ELB. It also seems to me that bows with excessive recoil are noisy.

[Kviljo]

My own pet theory is that a bow without handshock has limbs that straighten out near the handle before they straighten out at midlimb/tips. When such a bow slams home, there will be less mass in motion for the string to stop.

On the other hand, a bow that has much handshock, will have limbs that first straighten out at the tips/midlimb. - which means that almost all of the limbs mass will be in motion just before they gets stopped by the string.

Therefore, I think one should stress the limbs progressively more from the grip to the tips, if one should want to make a bow with little hanshock. If the outer parts of the limbs bend more than the inner, it will take the outer parts longer time to unbend than the inner, which means the inner parts of the limbs will stand still when the string stops the bow. Here one should probably also take into consideration that the outer parts of the limbs naturally will unbend later than the inner, because the outer is cast forward as they have to unbend, which means that it is perhaps not fully necessary to stress the outer limbs more than the inner.

Can it be disproven?

[Jesse]

kviljo That would explain why a whip tillered bow would have low shock. I have an old fg longbow that looks a little whip tillered and it is still the smoothest shooter i have. To bad its backed with f.G.      Jesse