Tag Archives: Setting Up Equipment

This Happens Far Too Often

This arrow shelf is “crowned” which means arrows can be “shot off of the shelf.” Note the material added to protect the bow (Velcro works great at this).

We had a light practice at the college yesterday (most were away at a competition) and one of the team members asked for help with his bow. I asked him what he was working on and he said his arrow rest. This young man is a Traditional Recurve archer and his rest was a metal wire stick-on rest, designed to be used with a plunger. In fact, shooting without a plunger was damaging his arrows because they were rubbing up against the rest’s bracketry. I suggested he use one of the club’s “loaner” plunger buttons and he set about installing it. I showed him how to adjust it and left him to it. (We learn manual things better by doing than by watching somebody else do it for them.)

When he finished he wanted me to check his installation. The button wasn’t out far enough, it barely protruded from the arrow rest, so I did a quick peek at his centershot and it was way outboard from anywhere good. What the heck? I looked more carefully at the bow (being more focussed before on the student) and noted that the arrow shelf was “crowned,” a design that facilitated shooting arrows off of the shelf. I dropped the arrow onto the shelf and … almost perfect centershot. Even with really skinny arrows, there was no way to shoot off of an elevated arrow rest. The only way I could see that the brass threaded insert could be used would be to bolt on a wrap around arrow rest, that would have to hang back over the edge of the shelf because the bow wasn’t cut with enough of a sight window to place any rest inside the sight window.

Who would make such a bow, I wondered? (I am not telling, and this is not the only one I have seen doing this, just let it be known that the buyer must beware when purchasing archery equipment.)

We did a few other things to allow him to “shoot off of the shelf” which I won’t recount but I happened to take a peek at his arrows. They were 350 spine. At his draw length, he would have needed a 65+# bow to make those arrows work. His bow is 42#. Thankfully, the arrows weren’t cut to his actual draw length and were a couple of inches longer, but they needed to be a couple of inches longer than they were to work in that bow.

Who would sell someone arrows so out of spine like that?

This shelf is flat and is not designed to be shot “off of the shelf.”

This is a sad tale. In many parts of the country, the number of archery pro shops has dwindled dramatically. I live in Chicago, and if you struck a 50 mile radius circle around where I live, you would have close to 10 million people inside that circle. To the best of my knowledge, there is one full-service archery pro shop in that circle. There are, however, a number of big box sporting goods stores that sell archery gear. Some of the members of one of the archery clubs I belong to work in such stores, so I know there is quality help available but time and again, bizarre sales are made from such stores.

A most common pattern is a newbie target archer goes to such a store and there is someone behind the counter to serve them. They tell the clerk they have a 30# bow and they need arrows. The clerk selects an all-carbon shafted arrow that they are having a special on (!) that is labeled 30#-50#, then measures the archer’s draw length (usually haphazardly) and cuts the arrows to the student’s draw length. This sounds right, no? It is dead wrong.

Many all-carbon arrow manufacturers got into the arrow game by selling a small line of good arrows cheaply enough to get sales. By designing the arrows correctly, they can cover the range of draw lengths that hunters need in maybe three shafts: 30#-50#, 50#-70#, and 70#-90#. With these kinds of shafts, though, you do not cut them to an archer’s draw length, you cut them to the correct spine. If those 30#-50# arrows are to be used on a 30# bow (with a 28˝ draw length), they have to be shot uncut.

Now, my student’s arrows were of a 350 spine, not one of these schemes. The spine chart for these arrows would have him shooting at 65+# at his draw length. There is no way to fit such an arrow to this archer. Either a mistake was made or a retailer was “clearing inventory” by any means at his disposal.

This AAE Super Flyte rest wraps around the riser to bolt on from the outside but needs considerable room inside the sight window to do its job.

Beginners, intermediate archers, and even some advanced archers do not understand spine charts and all of the criteria needed to fit arrows. They need professional help. I wish there were online programs on how to do this that were easily accessed and easily understood, but there are not. Please do not tell me about YouTube videos, the problem is there are so many videos posted on YouTube that it makes finding the right one quite problematic. I have suggested that major retailers and/or manufacturers set up a YouTube channel to address the equipment needs of these archers but that has not been done. We are currently developing several Internet training programs designed for coaches and archers but those are not yet done. (Maybe by summer.)

The implication for archery coaches is clear, if you want to be helpful, you need to inform yourself on these technical issues so you can be a source of clarity in the sea of confusion that now exists.

BTW I wrote a complete description of how to fit arrows and placed it into the team’s Dropbox folder labeled Instructor Materials. Now if I could just get them to read it!

 

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Personalizing Recurve Limbs

Recurve limbs tend to confuse beginners, intermediate archers, some accomplished archers, and even some coaches!

Sources of the Confusion
This will be about three-piece takedown recurve bows as they are the most common choice of target archers. The riser has a top limb and a bottom limb attached. These limbs come in three lengths (short, medium, long) which combined with various length risers, you can make the following bows:

Riser ► 23˝ 25˝ 27˝
w/short limbs 64˝ 66˝ 68˝
w/medium limbs 66˝ 68˝ 70˝
w/long limbs 68˝ 70˝ 72˝

Confused yet? (There are risers of other lengths!) Did you note you can make a 68˝ bow three different ways? (Generally, the shorter the limbs, the faster the bow, all other things being equal.)

The limbs then come in typically two pound (2#) increments over a fairly wide range of draw weights: e.g. 14#–48#. So, if you get “long limbs” and put them on a 25˝ riser, to make a 70˝ bow, and those limbs are listed at 32#, will you have a 32# bow?

Maybe.

Recurve limbs have their draw forces measured at 28˝ of draw. (Unless the bow is a youth bow for which it is common to measure the DW at 24˝ or a traditional bow, which are often measured at 26˝). Confused yet? But how many archers have a draw length of exactly 28˝? My guess is not too many. My guess is that most archers will have either longer or shorter draws. If their draw length is longer than 28˝, the draw force “in hand” will be higher than the weight listed on the limbs. If their draw length is less than 28˝, the draw force “in hand” will be lower than the weight listed on the limbs.

Well, if their draw length is exactly 28˝ will that be a 32# bow? Uh, maybe. Making limbs is not a perfect science. If a manufacturer makes a limb that is 31.5# do they discard it? No, they do not. It is “close enough” to 32# to warrant a 32# sticker and it goes in the pile with the rest. Now, don’t go all ballistic on the manufacturers about their sloppy manufacturing tolerances. These are quite reasonable numbers. If they do go “out of tolerance,” the limb is scrapped. And, if we insisted on perfect limb poundages, the price of limbs would skyrocket as so many would have to be rejected as not being “perfect.” (Since they can’t be recycled, so “Make another one, Bill, that one didn’t pass muster.” And if you have to make three to get one perfect one, do not expect them to be cheaper.)

FYI The manufacturers do not measure draw force like you do, they have a machine that clamps the butt of the limbs, fixing those in space. Then they place a force, in the old days this was a weight, on the limb tip and measure how much it bends. These “limb tip deflections” correspond to draw weights of assembled bows (the lower the LTD, the higher the DW).

What You Can Do to Lessen the Confusion?
As a coach, you can help get archers into a proper-sized bow. Youths need to avoid bows with too much mass as their bow shoulders aren’t very strong yet. Shorter archers need shorter bows, etc. Once an archer is fitted with one size of bow then you need to be able to address changes.

If they grow much taller, they may be ready to move up from, say, a 23˝ riser to a 25˝ riser. (Shorter risers have smaller sight windows and if the bow has a low draw weight, too, there may not be enough room in the sight window for all of the aperture positions needed. Longer risers are better for many reasons, but they are also longer and heavier than shorter ones.)

An Aside Bowhunters often use risers that are 20˝ or even 19˝ long. They can get away with such short bows, because their bows have to have a minimum draw weight of 40# (typically) and the shots they are taking are from fairly short range (20-30 yards).

Confused yet?

Changing riser lengths is a rare event (buying a new riser of the same length doesn’t pose fitting problems). Changing limbs is much more frequent. Enter the adjustable limb pocket! The first mass produced adjustable limb pocket was introduced by Hoyt archery, and which was so popular, the design was stolen worldwide; we now call it the International Limb Fitting, or ILF. This design was for a limb that pressed into the pocket, with a click stop, and a pocket that allowed the angle the limb made with the bow to be varied a little. Prior to the invention, you screwed the limb bolts in and out to attach and detach the limbs and if you wanted to make a limb angle change, you had to make (saw, carve, whatever) small wedges to slip between the limb and the riser and then screw down the limb bolts trapping them in between. This was more than a little bit of a hit or miss procedure.

An ILF Limb Pocket on a modern recurve riser.

With the new ILF design, the limb bolts were locked in place with a lock screw and the limb had a notch in it so it rode up to the bottom of the limb bolt (the butt having a “rocker” designed into it).

Note the rocker built into the limb butt. This allows an ILF limb to rock toward and away from the archer, restricted only by the position of the limb bolt.

When the limb bolt is “backed out,” the limb angles back toward the archer. This increase the brace height a little and lessens how much the limb gets bent at the archer’s full draw. Both of these lessen the amount of energy transferred to the arrows. But you can only do this so much before it becomes dangerous, so typically the draw force can be only reduced about 10% from the printed maximum on the bow. This amount of limb lean is so small that it is hard to see whether a bow’s limbs are “cranked down” or “cranked out” visually while they are being shot.

So, here is our quandary: recurve limbs (once a length is settled on) have their draw weights rated at 28˝ of draw (which your archer doesn’t have), may be slightly less or more due to manufacturer’s tolerances, and can be anywhere from the highest value of draw weight for those limbs to about 10% less than that depending on the limb pocket settings.

Got that?

If your head is spinning, you are not alone.

Try This Here’s a system that can simplify the situation for you and your archer. To use it you need a reliable draw weight scale (all measures must be made on the same scale). Here’s how to do it:
1. With your archer’s current bow, crank the limb bolts all the way down counting how many turns are being made in the wrench. The reference point for “turns” is the limb bolts all of the way down, so when we get there that will become the new reference point. If it takes three (3) full turns to get them all of the way in, then the limbs were “at” three full turns out from bottom.
2. Measure the draw weight of the bow at your archer’s draw weight. If they use a clicker, put one of their arrows on the bow and pull until the clicker falls off. Easy peasy. Write this number on the limbs with a Sharpie/permanent marker.
3. take 10% off of that full draw weight measure and write that number down next to the first one. That is the draw weight range for your archer’s limbs at that draw length. (Set your archer’s bow back to its original state when done.)

Moving On Up
If they want to increase their draw weight once they are “bottomed out” on their current limbs, they need to buy limbs of the same length, four pounds (4#) heavier. The previous limbs were bottomed out, the new limbs will be backed out, typically maximally. So, if moving from 30# limbs, you move up to 34# limbs and back them off fully (10% of 34 is 3.4 pounds) which gives your archer a net 0.6 pound draw weight increase, which is easily doable and he/she can crank it up from there.

No matter what their “personal draw weight” is, use the ratings on the limbs to make purchases. So, if the limbs were marked 28#, you move up to limbs marked 32#. Whatever their personal draw weight max is, it also will be increased 4# (approximately).

Their personal draw weight, the “weight in hand” is what you need for fitting arrows, etc. The marked draw weight is only used to identify limbs for purchase.

But, Wait, There is More!
Here are two sets of limbs and their maxes (in hand) for that archer:
26# limbs        29.5# max
28# limbs        31.5# max
He also has a pair of 30# limbs, can you estimate what they would measure maxxed out for this archer?
I came up with 33.5#. In each case the difference was about 3.5# and since all of these numbers are fairly close together, that pattern should continue. When the limbs get up over 40# I expect slight differences.

Now, just for fun, take off 10% from each of those max DWs to give a range for each set of limbs.
I get:

26# limbs 29.5# max 26.6# min
28# limbs 31.5# max 28.4# min
30# limbs 33.5# max 30.4# min

Can you see that the 26# and 30# limbs cover the same range (26.6#–33.5#) as these three do? There is a small gap from 29.5# to 30.4# when the swap from the 26# limbs to the 30# limbs is made but that is a reasonable “jump.” This is why it is recommended that you buy limbs in 4# increments (another blessing from the ILF system).

Note Realize that often more that 10% can be removed from a set of limbs so that gap is often much smaller.

Safety Note Never exceed the number of turns allowed in the manufacturer’s instructions!

If you try this system, let me know how it works for you or your students.

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Breaking News! Archery is Counterintuitive!

I got the following email from my best student this morning:
“Okay coach, explain this one to me. Increasing my bow weight seems to make my arrows shoot more to the left. Compounding my confusion is that tonight I got the groups to move back to the right by tightening my plunger. Count me confused and dazed!
Cheers

If this has never happened to you, you haven’t been in archery very long. The student in question shoots Olympic Recurve, so you have that as background. Here is what I answered, expanded for this post).

* * *

A bow is a closed system, when you change one part, many others are affected. (Memorize this!)

You got two counterintuitive responses to things you did. The problem is that ceteras parabus was nowhere to be seen. (Ceteras parabus is the principle that “everything else was the same.”) When you make a single change to a bow, you make other changes, too … always! There is no such thing as “everything else was the same” when working with bows.

For example, you increased your draw weight. I do not know how much but it was not a fraction of a pound is my guess. When you screw in the limb bolts, you change the angle of the limbs to the bow (making the limbs more upright as it were). This results in a lower brace height. (Plus more tension on the string at brace, plus …) The brace height is one of the determinants of the point in space at which your arrow’s nocks separate from your string at the end of the power stroke. Since the string’s path toward the riser is a flattish “S curve,” the change in the point of separation of the string and nock is complex. If the nock comes off more to the right from where it did previously, the arrow ends up pointed more to the left (the point has enough inertia that it doesn’t move as much as the nock end). If the nock comes off more to the left, the arrow will be pointed more to the right. (Think about it.) I have also to point out that when the arrow separates from the string it is no longer touching the arrow rest.

“Coaches need to expect counterintuitive responses to equipment changes.”

When you change the bow’s draw weight, you are also changing the efficiency of the bow due to a spine match or mismatch. I think I told you about the compound archer who lowered his draw weight (just a half turn on each limb) only to have his arrows hit higher on the target. What happened when he lowered the draw weight,  he created a better spine match (arrow to bow), which created a more efficient transfer of energy from bow to arrow which made up for the energy loss from the change in draw weight and more. These are the kinds of counterintuitive things that can happen.

If we had created a perfect spine match for your bow before (unlikely, such things take a great deal of time and effort), we no longer have that spine match. When you finish your draw weight changes, a complete re-tune is necessary because so many things have changed.

If you think the string goes straight toward the riser, think again. (Yeah, this is a stringwalking Barebow archer, but I get to exaggerate for emphasis, don’t I?)

A general consequence of this situation (reality actually) is coaches need to expect counterintuitive responses to equipment changes. This is because of the reasons stated and because what you were taught were often oversimplified rules of thumb. For example, “weak arrows fly to the right, stiff arrows fly to the left.” and “If you lower the nocking point, you will raise the hit point of the arrow on the target.” (All of these are for right-handed archers.)

These equipment aphorisms were intended to get you down the road until you could think through such problems without needing them. From a perfectly tuned bow, if the nocking point is lowered a slight amount, the arrow will hit on the target lower than it did previously. But if you lower the nocking point enough, the rear of the arrow will start hitting the rest or arrow shelf and where those arrows land is anybodies guess.

All of those pithy little rules need to be taken with a grain of salt. And, they need to be thought through as they are all true … up to a point. By thinking them through they provide an entry to better understanding of archery equipment. If you do not, they become unreliable crutches. (I am speaking from experience here. If I had a nickel for every mistake I made, I could have retired earlier.)

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Should Coaches Necessarily Be Good Archers, Too?

I was watching a golf instruction video and the coach giving the lesson demonstrated what he was talking about by hitting the shots as described. All of these coaches, even when quite old, still play very good golf. When the PGA certifies its coaches, there is a score requirement, that is coaches need to be able to shoot a very good score on a course whose difficulty has been determined (no cherry picking of a really easy course to set your mark, the easier the course, the lower the score required!).

“If you are a coach what should be expected as to level of your expertise with bow and arrow?”

In contrast to that requirement, in all of my coach certifications, and there are a good half dozen of those, I have never been asked to demonstrate my skill as an archer (or as a coach for that matter). I have only been asked to demonstrate my knowledge by passing a paper and pencil test.

And even further extreme is the professed belief of many compound archers that if a coach is not a current or former champion, they have nothing to teach them.

So, if you are a coach what should be expected as to level of your expertise with bow and arrow?

In golf, there are specialists who deal with the equipment: fitters, club makers, technicians. In archery, not so much, so coaches need to know enough about their equipment, its repair and replacement, set up, etc., to be able to help their students. Archery coaches also need to know about form and execution, competition preparation and strategies, and a lot more (training, nutrition, the mental game, etc.).

And, archery is a sport in which “feel” is important, so experience is necessary. An archery coach who has never shot a bow and arrow is at a distinct disadvantage in being able to communicate regarding how a shot feels. So, my opinion is coaches need to be able to shoot, or needed to have shot enough in their lives to address all of these issues. Further, if you want to coach, say, traditional archers, you need to have some experience shooting traditional longbows and recurves in traditional manners. Do you need to have tried every technique you might want to communicate to a student? Well, in a word, yes. Tried certainly, mastered, no. Mastery only comes from years of practice. Most coaches have a major discipline (recurve, Barebow, compound-release, traditional, etc.) and in that discipline they need to have developed a fairly high level of skill. Do, they need to be “championship level?” I do not know what that means, or rather, it means something different to different people. I have taken medals in tournaments with the word “championships” in their name, but I was hardly an elite archer, ever.

Some times the best coaches come from the cadre of those who were “less successful” but tried everything to become more successful and, hence, are more knowledgeable. I consider myself one of those.

Nobody “knows it all.” So, if you find yourself in the position I found myself, where there were many students seeking help in a discipline that was not your forté, then take some lessons in that discipline, acquire (borrow, buy, rent, whatever) the required equipment and give it a try. Sign up for a tournament in your new style to put some pressure on the pace of your learning. My specialty is compound but I have had more fun competing in recurve and longbow events (possibly because there was no pressure to try to win) and I certainly learned a great deal from those experiences. I got such a baptism, from a bloke who was encouraging me to learn traditional styles by him getting me to sign up to participate in USA Archer’s Traditional Nationals. He even made me a longbow to compete with. I was not in good physical shooting shape at the time and it was a long two days (York, American, and Clout Rounds) so I got very tired, but I had a blast … and I learned a great deal.

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Problems Tuning Genesis Bows

QandA logoI get a lot of requests for help and I am glad to provide what I can. One of my readers upbraided me for this because I have been more than a little adamant that archery coaches shouldn’t “work for free.” So, I am being somewhat inconsistent. There are a couple of reasons I do this. For one, I am still trying to learn how to “coach remotely,” so I embrace opportunities to do that. Second, there is so much need for help in the archery coaching community. The main reason, though, is that people are turning to me because they can’t find the help they need. Not that that help isn’t available in every case but that it has been made hard to find. (I really, really, (really) wish the archery organizations would embrace coach support wholeheartedly instead of the current “train ‘em and drop ‘em” approach.) Until such resources are more widely available I will continue to do as much as I can to help those coaches who seek it.

Today’s topic comes from a reader of this blog who seeks help tuning Genesis bows. Here’s his email:

I’ve been darn near driving myself insane trying to learn to understand and tune a bow, specifically the Genesis.

A little background: I’m Level 2 certified wanting to do level 3. Just having trouble finding a training that’s close and works with my schedule having five kids of my own. I’ve read many of your books and in fact own 4-5 of them as resources for me and our coaches. We have a very large NASP program of 95+ in our elementary school from grades 4-6. We’ve been doing NASP for 5-6 years. We’ve won a team state championship in our second year and some individual championships. I’ve not done anything to the bows except yoke tuning and nock point tying 3/8˝ high of zero on a bow square and the occasional serving repair at the local archery shop. Perhaps I should be tying the nock even higher.

I’ve talked to other coaches and have picked up a few tips/suggestions regarding bow tuning and done far too many hours of research. Most coaches, since we’re competing against them, I believe are a bit guarded about sharing too much info. However, it seems almost all of our bows make arrows kick to the left for a RH archer no matter what I do.

For bows that seem to have cam lean I’ve tried rotating the bottom limbs, fiddled with the ATA length by twisting strings/cables, and replaced bushings in the cams. Regardless, I still see arrows kicking typically.

I realize that when pairing archers with bows that are not their own in a program it is not a one-size-fits-all situation. However about 50% of our archers have their own bows and I’d like to be able to tune them properly but cannot figure it out.

Also, once we begin shooting as a team we have enough bows for those who don’t own their own bows to each use one of ours thereby allowing us to individually tune. As NASP has grown it’s become more competitive and I’m wanting to keep up but feel we’re being left behind and want to keep our kids competitive and give them every chance possible to win. I’m willing to do whatever it takes we just don’t know what that is when it comes to bow tuning for the Genesis. If you understand these bows I’d be willing to pay you good money for a private bow-tech clinic if you’re ever in the area, not joking. 🙂

I just read the below link where you mention attaching a guide to bow and arrow fitting to the article regarding but don’t see the text document mentioned. Perhaps it would help. https://archerycoach.wordpress.com/2016/03/03/porpoising-and-fishtailing-follow-up-and-the-acg/

Any guidance or assistance is greatly appreciated!

And here is my response:

* * *

The document mentioned in that post was attached to the email sent to the correspondent, not the post. I have attached it to this email in the hope it might assist you.

Everything I am going to say from now on applies to right-handed bows. If you are dealing with a left-handed bow, you have to switch left and right. ;o)

Your kids arrows are flying to the left and you can’t tune it out because the arrows are too stiff. The “Genesis formula” (my term) is to make a bow and arrow combination that can be shot by a great many people. So the bow has zero letoff, which allows it to be shot by people with widely different draw lengths with no adjustment (not so with a bow with letoff) and an arrow that is too long and too stiff for people with short draw lengths so that it will be long enough and not too weak for people with longer draw lengths. But arrows that are too stiff for a particular situation will fly off to the left. Arrows that are too weak, will fly off to the right. (Remember that left and right directions have to be switched for left-handed archers.) Since most youths fall into the shorter draw length category, most arrows used for the Genesis (especially the “Genesis Arrow” are too stiff and will fly to the left no matter what you do to the bow.

This is because the farther you draw a bow, like this one, the more energy is stored in the bow. The more energy stored, the more energy is given to the arrow when shot and the stiffer the arrow needs to be to receive it. (Imagine a whippy thin arrow being shot from a very stout bow–the arrow might break upon release!)

“So, in tuning, we set up the bow and tune the arrow.”

So, in tuning, we set up the bow and tune the arrow. (Little tweaks of the bow may take place for fine tuning purposes, so this is just a generalization.)

The hard thing with kids is that they are still growing. If you fit them for arrows (see attachment) “correctly” they will over the next six months, grow an inch or half an inch and their draw length goes up accordingly and now they arrows are too short (for safety) and too weak (as the bow is now “stronger” because it is being pulled farther). What we recommend is to fit arrows to youth’s bows that are one spine group stiffer for each extra inch of length you choose. By choosing to use an arrow that is 2-3 inches longer than usual, if you didn’t choose a stiffer shaft, the arrow would be too weak. But with those stiffer shafts, when the youth grows and needs a stronger arrow, that extra length allows the arrows to be shortened (making them stiffer) while still being long enough for safety.

Standard bow setup for “fingers” shooters is to have the bottom of the top nock locator 1/2” above square. The purpose of this is to launch arrows a bit “nock high” to avoid clearance issues with the arrow rest. Genesis bows are not what one would call high precision bows, so some cam lean and other less desirable attributes are to be expected and really don’t contribute to your issues. The problems you are having are likely due to just arrow shaft stiffness mismatches.

I hope this helps.

Steve

PS We are working on a series of e-booklets explaining all of this and the attached document is to be part of that, from which we expect to make a little money ($1.99 per booklet?), so I ask that you don’t share the document SMFAwith your colleagues. Of course, if you learn the knowledge provided in it, you will be free to share that with your fellow coaches. ;o)

PPS We have done bow maintenance and tuning workshops before and we might be able to set something up if you would like (we are not so far from one another geographically). There are, however, people in your community who might be able to provide this service cheaper (we need to recover travel and lodging costs, etc.). The purpose of this e-booklet series mentioned above is to provide much of the information you need. I also strongly recommend the book “Simple Maintenance for Archery” by Allan Anderson and Ruth Rowe. It contains step-by-step instructions for many of the tasks need for tuning and maintenance (with photos!). It is now out in a second edition (photo is of first edition).

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Is it My Equipment, the Environment, or Me?

When experiencing problems in archery, the key question for archers is: is it my equipment, the environment (wind, rain, etc.) or me responsible for my misses. Since you cannot solve a problem you do not know you have, this is something coaches have to help with as often as not. Believing one has an equipment problem when it is really form/execution is to road to nowhere.

Consider the following story from my friend Tom Dorigatti, a compound bow guru:

Do you remember me telling you that a careless person in the range went running (and I do mean running) past my bow and knocked it flying some 15 feet onto the hard concrete floor? Do you also remember me telling you that the silly thing was just not shooting well, or holding well, and was tossing flyers at will high and/or low out of nowhere?

I put on a new Hamskea arrow rest (taken off my Merlin bow), I checked axles and cams for straightness/cracks, misalignment. I rechecked and checked my measurements again. I found nothing that should be causing this. I do not miss by 12˝ or more at 20 yards, period.

“Well, I went a step farther and took a large magnifying glass and went over that bow from stem to stern looking for anything that may be a crack, or break in the limbs and/or the riser. I found nothing.

I have no way of checking for a twisted riser, however. So, we were down to either a twisted riser or a failure somewhere on the bow that we/I couldn’t detect. I called up Darton and explained what exactly had happened to the bow. I explained how it wasn’t shooting for crap, and that I would like to send it in for them to check out for a twisted or cracked riser. I got an RA Number sent immediately.

From the time I sent the bow in until the time I got it back was 10 days. They had asked for an arrow that I was using out of the bow and how I set the bow for its paper tune. Of course, I tune a slight nock high right tear because bullet holes for me doesn’t cut it.

I called them back after about a week and asked if they’d found the problem. They had. That idiot who knocked the bow flying had splintered (not visibly) all four limbs on the bow! What was happening is the splinters were opening and closing at their will and state, and not consistent because they were failing worse as time went on.

“What is important for coaches to do is to listen to these stories.”

The riser was checked and it wasn’t bent or twisted. Darton replaced all four limbs on the bow, and set it back up to factory specifications, which so happens to be exactly where I had it set anyway! Of course, I checked all settings before even trying to shoot the bow, and I guess it was right by them, since they told me they checked the tune after they’d rebuilt the bow.

Now the thing shoots like it is supposed to and I’m not fighting the nose-dives and wild arrows. It is shooting as tightly (or a touch tighter) than I am able to hold, so I don’t have any complaints.

In spite of the fact that the bow had been “abused” (not my me, though), Darton replaced all four limbs, reset things, and sent it back at absolutely no charge to me.

I now have a bow that holds steady now, after months of fighting it and blaming myself. because of the “shake,” when all the while most all of it was broken/failing limbs. I was lucky … because those four limbs could have broken all at once at full draw and … that is not nice to think about!

My sight movement since I started shooting has always been an up and down movement. Rarely do I ever have a side to side swim of my sight. I don’t have very many left and right misses either. So, I should have known that there was something really out of kilter with the bow when it kept getting worse and worse as time went on. But, I blamed form, and that shake because I went through all the measurements of the bow and they were spot on.

My suspicions really arose when it got to the point I couldn’t find anything else. I knew I was fighting the bow constantly. I had a friend shoot the bow and he said he struggled to keep the bow up close to center; it was like he had to fight the bow to keep it from having the sight drop out the bottom, too.

Another thing that put me onto the bow being screwed up was paper testing. I always shoot six different arrows when paper testing, not just a single shaft. Who the heck knows, you could pick a good one or you could pick a bad one, but when all your arrows give the same tear, you know things are good. With the “broken” bow, I was getting several tears per my tune, then a wild nock right tear of 2-3˝, then back to a “normal tear” for a couple, then a another wild tear. And it wasn’t the same arrow each time. Sometimes I could get three or four in a row, and rarely five or all six. That finally convinced me that something on that bow was moving around or changing as the bow was being shot.

“So, coaches, keep your ears open. Ask questions of the story tellers. Keep mental notes.”

The reason I am sharing this long story with you is because it was a long story. Here was a very, very careful archer, an archer who documents his equipment very carefully, an archer who is very cognizant of his own shot details, and an archery who has loads of experience and it still took him a great while to finally come to grips with the real problem.

When recurve limbs have interior defects, they eventually show up as limbs that look deformed, but compound limbs are shorter and typically solid fiberglass and do not necessarily show signs of internal damage.

What is important for coaches to do is to listen to these stories. From them you can glean knowledge but also they can give you an appreciation of how hard it is to diagnose some equipment problems. Because Tom is such an experienced bow mechanic, it took him longer to eventually send it back to the manufacturer with a note “It’s broke, can you fix it?” It is a matter of pride for both Tom and I that we can fix almost anything that goes wrong with our gear and it can cost us time and money and effort to overcome this belief.

It is also important to listen to these stories for examples of good and bad behavior on the part of the manufacturers. Darton showed itself to be a quality company. I have had equally good service from other manufacturers. But when an archer has a bad experience with a seller or manufacturer, he then tells that story repeatedly for the rest of his life! This contributes a lot to a feeling of negativity floating around archery and it is nice to be able to note times in which a positive result happens.

So, coaches, keep your ears open. Ask questions of the story tellers. Keep mental notes. The deeper you get into coaching, the less obvious equipment problems become (the easy ones are detected and fixed easily). There aren’t any textbooks or training programs on how to help your student-archers with equipment problems … yet, so you have to find ways to educate yourself otherwise.

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Compound Letoff—More is Better, Right?

Letoff is what makes compound bows special. Without letoff, compound bows are just a mishmash of wheels and pulleys. But, with letoff, wow!

If you are unfamiliar with the concept, compound bows incorporate mechanical advantages to have the draw force of a bow ramp up faster than recurves and longbows and then when they reach “peak weight” the force drops off down to a much lower “holding weight” at full draw (see illustration). Because of that faster ramp up, the total energy stored in the bow is greater for a 40# compound bow than for a 40# recurve or 40# longbow, even with the force give-back from the peak weight to the bottom of “the valley.”

The most typical “letoff” is 65% but when they were introduced they were 30-40%, then 50% became popular, then 65%, and now bows with as high as 80% letoff can be purchased. The letoff percentage is how much of the draw force is taken off, so a 40% letoff would reduce the peak weight by 40% at full draw. A 60# compound bow with 67% letoff leaves the archer only holding 20# at full draw, twenty pounds! The other 40# or so has been thrown onto the cabling system so that, in effect, the limbs help pull one another.compound-draw-force-curve

So, being Americans, we think that if letoff is what makes a compound bow special, we want “to get me some more of that,” and the more the better.

Unfortunately this is not necessarily a good thing.

One can design a bow where there is almost 100% letoff and you would be under almost no strain from the draw at full draw. But for target archers this is definitely not a good thing. We want to have enough holding weight to get a clean launch of our arrows. Even with release aids, a very low holding weight (aka a high letoff) means that only a small force is needed to change the launch position of the rear end of the arrow. Therefore it is easier to mislaunch arrows. This is the same consideration with recurve archers who do not have enough draw force “in hand” to get cleanly off of the string. (The hardest bow I have on hand to shoot is a 10# recurve bow. Getting off that string cleanly is very difficult.)

Most compound target archers seem to have gravitated to about 65% letoff. I say “about” because exact letoff cannot be built into a bow. If you change draw weight, or brace height, or any number of things on a compound bow, you can change the letoff involved (not hugely, but some).

Hunters are more prone to use a bow having 80% letoff as they will only be taking a few shots, may have to shoot from an awkward position, have larger targets to hit, and may have to wait for a moving target to clear obstructing brush or turn for a clean shot. The extra letoff allows more time at full draw.

More time at full draw is the advantage of letoff. Because of the lessened strain on the archer at full draw, they have more time to align their bows correctly and then aim carefully. When peak bow weight happens at full draw, as it does with recurves and longbows, time at full draw is necessarily short and less care can be afforded.

 

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Bowstrings: A Quick Survey

I had a lesson the other day with one of my Olympic Recurve students and he was complaining that the bowstrings he bought for his 68˝ recurve bow produced brace heights that were too high, even with no twists. I asked if the strings had been “shot in” and he said they were.

Bowstrings made with modern materials need many fewer shots to temper them than do older materials (Dacron and earlier). The old rule of thumb was 100 shots were needed, now I would estimate 30-35 should be recurve_bow_stringsufficient. After any stretch has occurred, the string is twisted to create the desired brace height. But this process is of no help if the untwisted string is too short.

This situation reminded me that on many occasions when buying large numbers of bowstrings for archery programs that many, if not most, were too short, producing quite high brace heights. On beginner bows this is not so much of a problem, the only one I could think of is making sure the archer’s armguards were placed farther from the wrist to provide the protection necessary. But on recurve bows of serious archers …

So, here is my question (please respond with a comment):

Have you experienced buying commercial bowstrings that turned out to be too short for normal use?

Any wisdom you want to share regarding how you cope with this would be nice. (I make my own bowstrings, but this is not an option for most archers.)

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Central Plane ? of the Bow?

QandA logoI always assume I am being perfectly clear, but I get help from readers who write to me and tell me when I am not. This is something for which I am grateful as it helps me do a better job of explaining things. Here is a recent request for a clarification that I thought I should share.

On page 64 of The Principles of Coaching Archery, Vol. 1, you say that the sight aperture [should be] in the central plane of the bow (along with the bow string). I’m not sure what you mean by ‘sight aperture,’ and not sure about ‘central plane.’
“I’m assuming you don’t mean that the pin (or whatever) that is part of the sight should be obscured by the bow string. I shoot a bare longbow for practice, but I hunt with a compound bow that has a sight, and it wouldn’t do me much good if the pin were hidden by the bow string.

Here’s my response:

* * *

I usually ask whether you want the long answer or the short one, but …

If your bow is set up right (any of them), the bow string should share a plane with the riser. The riser, were it to be split in two slicing down its middle from top to bottom (from the archer’s viewpoint), that is what the “central plane” is. (If you have a metal riser, the screw holes on the back are in that plane so you can use them to visually check whether the bowstring is “in plane” in that it should line up with both screw holes. On recurve bows, before the advent of “adjustable limb pockets,” the string could be no other place. If you bought a bow and the string wasn’t aligned on the center of the riser, you sent it back. (If later, you acquired a twisted limb, then there is more than one problem involved.) Now that we can “adjust limbs in their pockets” I have seen bows with bow limbs tilted in the same direction, creating a situation that the bowstring was quite far from centrally located. These bows don’t shoot worth a darn if left that way.)

See how the bowstring ;ines up with the central plane of the riser, how the archer holds the bow vertically? All of these are needed criteria for repetitive accurate shooting.

See how the bowstring lines up with the central plane of the riser, how the archer holds the bow vertically? All of these are needed criteria for repetitive accurate shooting.

Ideally when the string is pulled back and let go it moves toward the riser in or near to that plane. The arrow needs to be set up so that it sits in or very near to that plane so that the string pushes it along the axis of the arrow. If the string pushes on the back of the arrow and the arrow is sideways to that plane the arrow will spin like a helicopter blade! So, a basic bow setup requires the string and arrow to sit in this same plane. The arrow should, if it is spined right, then fly in this same plane toward the target, which means the sight’s aperture (pin, ring, scope with dot, scope with a ring, whatever) must also be in that plane (dead center, please).

When I first work with an archer, one of the first things I check is whether his/her aperture is “in plane.” If it is not, they do not have a good tune. The equivalent, if you are shooting Barebow and using a point of aim aiming technique, is that your POAs need to be in a vertical plane with the target center (a 12 o’clock to 6 o’clock line through the X-ring is part of this plane which, interestingly, is the exact same plane we were just talking about). If your POA is to the left of that line to hit the center, then your arrows are too weak (assuming a RHed archer). If the POA is to the right of that line, your arrows are too stiff.

All of this is determined by bow design and by the fact that when an arrow flies the only force remaining on it is gravity, so the arrow moves up and down only (absent wind) after it is launched. If that arrow doesn’t start in the central plane as described, it will not end up in it and will not hit the center of the target.

If the bowstring were off-center on the bow, it would tend to twist the bow in your hand and also end up pushing your arrows in a direction other than down the length of your arrow shafts and so your arrows would be hippety-hopping all day long (fishtailing primarily).

I am in the process of pushing a “principles-based archery coaching” approach in which coaches can learn a few of these basic design/physical principles which then allow them to figure out what is going wrong with bow setups, no matter the situation. Ain’t there yet, but working on it.

As to hiding the sight aperture (pin, ring, scope with dot, scope with a ring, whatever) compound bows allow the use of a peep sight which allows you to look through the string and for other bows, it is important that the pupil of your aiming eye (the hole that lets the light in) is lined up along side the bowstring, tangent to that string, meaning as close to the “plane” as possible without having the string block your vision.

And, of course, when you shoot Barebow, there is no sight aperture to place correctly or incorrectly.

An Added Note Now that you have some idea of this central plane of a bow, can you now see why a bow sight’s sight bar (the vertical part when being used) has to be parallel to the central plane? If it is not, then when you move the aperture up and down to adjust for shots of different distances, you will also be moving the aperture left and right relative to that plane. This will create left and/or right misses depending on the angle of the sight bar (the amount of the miss will vary with the distance).

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The Relationship between Draw Weight and Stabilizer/Bow Weight

QandA logoI love it when I get questions I had never thought about before. When you learn a subject, it tends to channel one’s thoughts, thus avoiding questions that can challenge them, so it is good to consider such questions. The question that stimulated this flood of philosophical thinking was: “If I increase the draw weight of my bow should the weight of the stabilizer also be changed?”

* * *

At first this seemed like one of those questions beginning Olympic Recurve students ask that are inherently nonsensical, but this one is not.

The “stabilizer weight,” including how that weight is distributed, is primarily a matter of balancing the bow as well as resisting movements that can occur in the short amount of time the arrow is on the string and moving (~ 20 ms). (The long rod of a OR setup resists the bow from tilting up and down and twisting left and right, while the short rods resist the bow from rocking left and right or rotating around the axis of the long rod. About the only motion they don’t resist is movement along the axis of the long rod, which is normal and acceptable. Note, though, that the biggest source of movement resistance is the mass of the riser itself.) The draw weight is a matter of force applied to the string and riser by the archer. The weight of the stabilizer and bow is also a force but it is at roughly a right angle to the draw force … and the two do overlap some. (If you didn’t know that weight is a force, you weren’t paying attention in middle school science class.)

The deepest part of the grip of your bow (called the “pivot point”) is typically the midpoint of the length and mass of the bow. Your bow hand is mostly below that point so the bow draw force (created by your two hands and the musculature and skeleton between them) is pulling the bow back into your bow hand but also partly upward, too (like the way a construction crane works (see illustration and photo), the pull of a cable from the bottom causes the top of the other end of the crane to rise, including any weight attached to it). So, like the crane, the draw hand is supplying some of the upward force needed to hold the bow up against gravity. When you raise the draw force, you increase the amount of this effect and it is easier to hold the bow up at full draw, that is the bow “feels” slightly lighter. So, you could add more weight to your bow or take some off if it feels better, but there is no reason to try to compensate for the increased draw weight other than that.

The bridgework bit is like your bow arm. Pull on those cables and the arm will move up. (The draw force is the equivalent of the pull on the cables) And, yes, I know that the cables can also lift what is on the end of the hook without moving the arm, sheesh!

The bridgework bit in this crane is like your bow arm. Pull on those cables and the arm will move up. (The draw force is the equivalent of the pull on the cables.) And, yes, I know that the cables can also lift what is on the end of the hook without moving the arm, sheesh!

There should be no effect of the draw weight change on the feeling of balance at full draw, even though the strain you feel at full draw has gone up. That increase in strain is horizontal, not vertical. So, if your bow still feels nice and balanced, you are good to go.

The bow arm acts like the beam of the derrick, with the draw force being like the force acting through the cables. This produces a slight upward force at the bow hand which helps to hold the bow up.

The bow arm acts like the beam of the derrick, with the draw force being like the force acting through the cables. This produces a slight upward force at the bow hand which helps to hold the bow up.

Realize, though, that since your “back half” takes on part of the work of your “front half” as described above, once you let the string go, then it is harder for the front half (your bow arm specifically) to absorb the loss of help from the draw arm and “dropping your bow arm” after the shot becomes more of an issue. We do not want the bow arm to drop soon after the shot because of “normal variation”—sometimes the drop will occur later (no problem) and sometimes sooner. If the “sooner” instances involve cases in which the arrow is still attached to the string, the dropping bow will take the string and arrow with it and a low shot will occur (definitely a problem). The indicator for the form flaw “dropping your bow arm” is that low arrow hits points show up out of the blue, as we say.

 

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