# Why ergonomics "feel well"



## Chuck Daehler (Mar 17, 2015)

Ergonomics are sometimes fully employed on slingshots, sometimes partially employed and other times completely or nearly completely omitted from slingshot frames. it depends on several factors as to the use of ergonomics.

This is intended more for the beginner than those who have made or purchased all types of frames, from the basic straight natural fork to the super ergo models...that is, with deep finger groves and/or other hand fitting features.

The ultimate ergonomic frame would be a grip which would look like someone squeezed a hunk of modeling clay in one's hand to make an impression of the palm and all fingers/thumb, then made that into a slingshot's grip area. Some, although rare, slingshot grips resemble that idea. Bill Hays' and Wingshooter (Roger) make frames with finger groves, index and thumb recesses and palm swell features which "fill the hand" well, distributing forces over large areas of the hand instead of localizing the forces of pull on smaller points of contact. This results in a more comfortable grip.

Why a more comfortable grip?

1. When shooting a lot of rounds in a session, localized forces soon become uncomfortable on areas where underlying bone pinches the skn against the frame. Sustained shooting especially with stronger elastic then becomes uncomfortable and actually distracting. For hunting where a shot may happen every few minutes to every few hours, or short shooting sessions involving shooting a small number of times,, ergonomics are therefore not that important.

2. Some simple frames can slide around in the hand resulting in variables in stance and at times on cold days, the frame actually flying out of the hand, impacting on one's face. Recently a post was made that a frame slid out of a shooter's hand and broke a tooth. When the hand is dry and cold this slippage is more prone to happen, although it is rather rare to be honest amongst experienced shooters and more prone to happen amongst new shooters.

3. Some claim a more comfortable grip increases accuracy. Actually it does not, but it does improve the shooter's "feel" for a frame and that contributes to a more positive mental stance towards it, subconsciously, improving the liklihood of hitting a desired target. If someone likes a slingshot for any reason, such as beauty, feel, or whatever positivity it imparts to the brain, naturally the shooter tends to shoot it better for psychological reasons....and for a longer sustained shooting session. "Gee this frame feels good, I can shoot it all day!" is a statement we see often enough when someone is pleased with a particular frame.

Why does an ergonomically fitting grip feel better than, say, a straight pole like handle, like the old Wham-o board cuts or a simple natural fork with a broom handle grip?

The torque forces are localized in smaller contact points on a non ergo frame than with a form fitting frame. So, the more surface area there is to absorb the forces of pull, the less localized the forces are on the hand. An arm brace such as with folding arm braced commercial slingshots or "shuttle craft" or "star ships" further distributes the forces of pull so a very minimum of localization or concentration of forces exist on any one point of the hand (and wrist and arm) in the case of braced or lanyard accessories).

The diagram shows the forces of a slingshot frame. The fulcrum is the point of rotation such as a teeter toter has a fulcrum in the middle...the principle of a lever. The fulcrum in the diagram is in blue...it is the center of rotation caused by band pull. The forks pull backward toward the shooter while the base of the handle pulls forward.

Obviously, supplying the most surface area to the force localizations distributes the forces over broader areas and thus becomes more comfortable to hold. Take for example a woman's spiked high heel shoe, using the heel as a striking surface in self defense. All the force of the blow is centered on a square centimeter of space and can be very effective in causing the assailent to pause or desist. The same strike with a purse impacts a much broader area, say 100 square centimeters of area (10cm x 10cm = 100 sq. cm), much less LOCALIZED, and has minimal to no delitarious effect on the assailant.

The red areas in the diagram are the force distributing areas. You can see by using deep finger groves and a deep well to house the web of the hand between the thumb and forefinger, the area absorbing the force is much more, than no groves or well at all.

This is why some makers buiild in ergonomics when fashioning a frame. Slanting the handle as in star ships and shuttle craft also permits the handle to be held in a natural way instead of using muscular tension to position the frame correctly on the target.

Bill Hays, inventor and designer (and martial arts instructor for years) has developed ergonomics to perfection as well as other makers, which enable the shooter to, with eyes closed, grip the frame whereby when the eyes are opened, the frame is oriented to the target perfectly on the X and Y axis...(the Z axis is clockwise or counterclock wise rotational in relation to the target and is personal preference...also called "vertical" vs "gangster or gangsta" hold style) that is, the frame on a true ergonomic frame self orients and is perpendicular to the target instead of canted or slanted one way or the other. That is a properly made 100% true ergonomic frame.

Ergonomic frames which fit a hand PERFECTLY likely would fit PERFECTLY very few people, just the person for whom the frame is made or like handed individuals coincidentally with like hand, arm bone structure. Hence, commercial frames have to give leeway for "most" shooters and can't exactly fit everyone absolutely perfectly like the modeling clay example at the start of this article. Frames come in sizes from many makers however to accomodate various sized fingers and hands and bone structure in general. The most commonly sold slingshots are ones which fit most of the people most of the time. Some makers will custom make a frame for a given customer. The extra time it takes is awarded a higher price of course but can be worth it for discriminating shooters, just as custom made clothing, gun stocks, golf clubs, any sport equipment in general, shoes or custom made cars, homes, and executive office chairs are. A generic row house, one of fifty, will cost less per square meter than a custom built Better Homes And Gardens master piece of the same square meters much the same as a generic big box store slingshot will cost much less than a hand crafted form fitting excellence in frames costs...yet both shoot with the same accuracy given the forks, pouch and bands are the same just as a custom house keeps the rain off and the inside environment comfortable to the occupants just as well as a designer home would.

Building your own frame can result in a frame that's just for you and feels super comfortable and this forum encourages members to do just that, roll your own frames...as well as patronize known good makers of slingshots who have satisfied thousands of users.


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## Chuck Daehler (Mar 17, 2015)

Here is an example of opposing torque using finger holes, in a world record setting slingshot, similar to the idea I employed on the slingshot pictured in my "avitar" which Cal sent me since I'm a frame with finger hole fancier. The bottom part (reference to the ground being bottom) of each hole would oppose the back torque of pull. A few similar "brass knuckle" designs have been offered in galleries on this forum, one was a puzzle piece recently posted by a very able and noted member from Spain.

654 fps was achieved with this slingshot. Actually, it was the bands/ammo that did that, just about any fork would have done the same. Band design (tapered possibly) and draw weight, band material itself, pouch profile and mass, ammo mass, and draw length are the deciding factors in velocity.

The U.S. Army did tests during WWII of spring loaded arms, not air guns but straight spring power to the projectile and found that anything under 700fps would not penetrate clothing, say, military uniforms and issue jackets, worn on the body, and sufficient velocity from a spring loaded arm was not achievable, therefore the project was scrapped.

Although housing each finger completely isn't necessary for counteraction of pull torque, it does serve as a "brass knuckle" device I guess., but more importantly, the whole bottom side of each finger absorbs back torque force whereas only finger groves permit only part of the finger to absorb the same force, resulting in the finger hole design spreading the force out to the maximum surface area of the fingers Interesting plywood design, and this can be made as a "take down" model to make it carry flat, an interesting idea.

The shorter the forks are the less mechanical advantage they have to produce back torque. Note this slingshot has probably the minimum height fork as well as likely the minimum width. Some of my slingshots could have shorter forks. Too short however and the bands get congested as they contract and the pouch approaches the fork opening...also too narrow results in band congestion I found and fork hits and fliers often result...without the wrist flip shooting method.

Design options/improvements:

1. If this was not a take down, I would employ a thumb rest.

2. I would put an extension over the web of the hand (area between thumb and forefinger) to absorb some back torque.

3. I would use slots instead of any other band attachment method to the fork.

4. I would employ a lanyard.

5. I would make the handle part thicker still.

6. I would add a palm swell. This handle actually dips inward, exactly opposite the way I'd make it to fill my entire hand with handle.

7. I would lower the entire fork "U" about an inch, as close to the index finger as possible, so it would not torque back so much. The lower the fork base is to the index finger, the less mechanical advantage the pull would have to produce back torque.


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## Cjw (Nov 1, 2012)

If you grip the fork closer to the fork tip like MJ , Keith Dighton, and other top shooters you don't have the torque against your hand and wrist like a Hammer grip with longer forks. Look at the way Keith holds his slingshot on you tube. And he can hit a 9mm ball with another 9mm ball. He makes some really great long shots too.


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## ImEggscellent85 (Mar 3, 2015)

Nice write up Chuck! Although I am a novice on making my own slings the few I've made are ergonomic. I am a advanced shooter. Be it hammer grip or pinch OTF or TTF best advice is make something try something that feels right and comfortable to you. For example I have mild Cerebral palsy so I need a small ergonomic design that won't cause my hands to cramp or lock up during shooting sessions usually 200 shots. I've recently taken a liking to bb shooters and PFS cause of the small ergonomic design, I am currently working on two aluminum frames from Metro Made one with a palm swell and the other I am trying to hunt down some avocado wood for scales. They will be custom fit to my hand as well as my wife's (small hands). I will post when completed first two laminated slingshots ever attempted.

Back to the subject It takes time and practice to get a feel on your own body's preference of holding, style and feel of aim and the weight of the ammo the pouch you have to feel it all. Practicing all aspects of the (feel) tunes your muscle memory providing you do it correct and safely for whatever style is used it becomes a part of you, when that happens your accuracy is what you can see in reasonable distance(bands ammo set up) what you see is what you can hit but only with practice. 
As for torque I like to point the forks down while pulling back the pouch for extra power so I need something that is anchored safety in my grip whether I sweat or weather I will maintain grip.

That's my two cents. 
Very good detailed write up enjoyed reading it and very nice slingshot.

My ergonomic design. 









Sent from my iPhone using Tapatalk


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## Alvin261084 (Oct 25, 2014)

wow... thanks a lot Mr. Chuck for a looooooooot of information here..... ^_^


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## ShaneO (Oct 14, 2015)

Good gravy Chuck that is a GREAT write up I have read it twice now and am still digesting it. I really like your thoughts on this subject so much that i would like to try a finger hole sling because as it turns out I think that my body wants to be a hammer grip shooter while my mind wanted to be a pinch grip. Can anyone suggest a vendor for this type of sling?


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## harpersgrace (Jan 28, 2010)

great write up and while I am sure for most "ergonomic" is the way to go, for me I have never held or shot a ergo (and I have tried many) that was as comfortable and as easy to shoot as a plain, un-carved, un-shaped natural of course I'm not going for any records, fancy shooting, or 1000 round sessions and I'm sure not a discriminating shooter....just goes to show everyone has different wants and needs. Again great post and thank you


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## Chuck Daehler (Mar 17, 2015)

Thanks guys! Sometimes I like to produce a tutorial on something I think others may benefit from, and from a thread of ideas it spawns for comments...not just mine...afterall, it's a forum. The idea is to experiment and find what's best for the job and your hand...I'm just giving some thoughts on the ergo aspect itself, hehe, certainly not saying "this is the best"...for it is NOT THE BEST, it's just that some in my collection are super ergos and some are not...and I enjoy shooting all of them.

My hands are a bit arthritic in the fingers so a super ergo "glove" type design seems to fit and feel best to me. I've got some pretty straight handled slingshots too and shoot them, but with lighter bands than my ergos have. The ergos permit me to comfortably shoot heaver banding for flatter trajectory using heavier ammo but light banding and light ammo is just as fun. Psychologically I do like to shoot up a steel paint can, yet I dont' hunt, so heavy banding and heavy ammo is just a psychological need for me at times...cannon fire! hehe

And yes, if one chokes up on the fork with thumb and forefinger, there is much less torque on the wrist and hand, hence all the popular designs thereof. I've tried that and that hold just isn't too comfortable for me which is why I settled on hammer hold. I made one slingshot that accomodates both hammer and fork pinch just to really try both on the same frame...and I settled on the old hammer hold method as best for me.

I want to make a Bill Hays Harpy which is a combination of super ergo and fork pinch, I have a feeling I'll really like it.

I think one reason hammer hold for me is "right" is that I learned when I was a kid using hammer hold, the fork pinch wasn't invented yet nor frames which were made for it. So it may be the little kid in me that prefers "the old way". New shooters, I'd encourage them to try both, hammer and pinch, so that they don't have that little kid preference built in.

I can't edit the post but I should have included at the top of my disertation that this ergo design and theory, is for hammer holders mostly since much of the torque is taken up in a different way using a fork pinch hold. Also, I had a beautiful finger hit using that method which was spectacular (bled like a stuck hog) and psychologically I cringe to think about it, yet the most popular hold is the fork pinch hold by far. A minority of us I think, use hammer hold. The Moor Hammer and Rambone so popular in Europe is a straight hammer hold frame yet I don't particularly like them. The low forks lessen the torque but need a wrist flip to assure no hits at the base of the fork. I tried one such low fork design from a "saved HDPE" which my dog ate..I had to shorten the forks, and got a couple fork hits on the base of the "U" yesterday. But not giving it up, I angled the frame forward a bit when shooting after that and it seems to cure the problem without the annoying wrist flip technique.

OK guys, let's see some ergo experiments and pinch hold experiments similar to the Hathcock and Harpy in style and function while not forgetting the good ole Y tree fork either. I've regressed to natural forks but with ergo lately.

My gallery is under my wife's account, Susi, if you want to check some ideas. I don't see much point in having two galleries. I got the finger hole idea from Bill Hays and another poster and have made three of them. For some reason they feel better generally because my index finger is not squinched around a frame, instead, the grip is better for me since it's extended in a loser radius. Bill Hays brings this out with his famous Hathcock (HTS) and Matt you'llshootyoureyeout and other makers also use a design that uses the fingers more extended than a tight wrap around.

I might add that a super ergo design takes about 7 times longer to make than a simple natural fork that has minimal sculpting, at least fo rme, and about three times longer than a semi ergo. The rasping and sanding steps are what take up the time. This is one reason you don't see super ergos in commercial production, ambidextrous designs sell better (obviously), but ambidextrous designs are comfortable for both left and right handed shooters as demonstrated by you'llshootyoureyeout and Bill Hays and others who produce nice ergo ambidextrous frames.


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## Byudzai (Aug 31, 2013)

howdy chuck,

I think it's worth saying that ergonomics can go beyond the grip and pertain to other factors like pocketability. I abandoned my early efforts at a perfect ergonomic frame because I found I would always pass them by in favor of smaller and flatter slingshots when it came to walking in the woods.

everyone falls in love with their own designs and I'm no exception. within the constraints of a frame that will fit in a pocket, my FlatCat gives me the most ergonomic grip of all the designs I've tried. I won't be surprised at all, tho, if I change my mind down the road and move on to another shape.


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## Bill Hays (Aug 9, 2010)

Good information Chuck.

Ergonomics is second only to function in my book.... and if you can get the two to work together, you're looking at something pretty special!

Certainly a nonstressed hold will always be preferable to a stressed one... and quite often I'm called upon by others to design a special slingshot for arthritic and or weak hands.... so things like extended beavertails and handfilling structures come into play, as well as simple biophysics and regular physics...

Combining sculpture and science to make a more pleasant shooting experience (or to make it possible at all) is what I feel slingshot ergonomics are all about.


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## Chuck Daehler (Mar 17, 2015)

I agree whole heartedly, ergo compromises pocketability insofar as mine are hugely fat and bulky...other frames that have ergo such as Matt's, Bill Hays' and others have a lot of nice ergo built in but more pocketable than my elephants. There is a huge need for flat pocketable frames, folding wire frames with arm braces (especially for strong pulls needed for sling bows) and A+ plywood frames exemplify easy to make pocketable board cuts.

I just posted this for those who want to putz with sculpting an ergo or two to add to their varied collection. Since I don't carry a slingshot around much other than on my farm, I don't need pocketability or concealment so much as the average shooter does, especially those who do carry an SS with them almost everywhere (and many do). So to put forth the info of the benefits and physics of a fat ergo design, I posted the above.

I might add that thumb rests are really a good thing to have for a super ergo "fits like a glove" frame. Mine without a thumb rest are not as comfy 'for me' to shoot, as with them. I stress, 'for me'...no one can make a blanket statement of what's 'best' for one's style and muscular/skeletal makeup.

I see more frames with some ergonomics cut into them lately.


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## Tex-Shooter (Dec 17, 2009)

Talking as a old man with arthritis, finger grooves tend to hurt my hand, if not a lot of surface area for them.


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## VAshooter (Feb 10, 2015)

This is a great thread. I liked Chuck's information on ergonomic slings and the mental and physical aspects of shooting by ImEggscellent85. Developing the "feel" for the way you shoot is critical for becoming a consistently good shot.


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