Just When We Thought We Knew Everything About Grippers

[John Szimanski]

Well, we have discovered another gripper issue - specific handle length. Here's where we are right now. You may have noticed the 'dogleg' issue on the GripPage. Well, we have also found yet another inconsistency in grippers - the overall handle length, even between the two handles on the same gripper, can vary significantly. We started with the SOS grippers with a tight spec on 'the distance between the bottom of the coil and the top of the handles' for consistency. We were able to meet that spec and produce very uniform grippers. Then we discovered the handle length discrepacies in other grippers and their different general overall length than ours. To address this we have revised our spec to set the overall effective handle length (from the top of the coil to the bottom of the handle) at 5-1/4" with a tolerance.

The varying handle lengths means, if you have two grippers rated at the same closing torque, the gripper with longer handles increases the moment arm thus making it easier to close. Likewise for a gripper with two different handle lengths, the shortest handle should be placed against the palm to take best advantage. The same concept applies to the dogleg - it should be placed against the palm to get the greatest advantage. Worst case - your long handle is on the dogleg - then what do you do?

Our tight initial spec ended up making our effective handle length acceptably consistent. But they were also generally shorter than IM and others. That means, our grippers with the shorter handles (some of which have shipped) will be tougher than grippers with equally rated torque and longer handles. All of our grippers that we have not shipped, and a new batch of higher rated grippers, are being revised to meet the 5-1/4" effective handle length spec. Discovering this new quality control flaw in other grippers forced us to rethink, revise, and set us back timewise. The first step already created a better gripper; now it will be better still. We have found yet another 'unknown' and are moving on it to nail it down.

Here are some of the measurements we have taken:

(2)3

5 3/16, 5 1/4

4

both 5 3/8

3

both 5 1/4

BBM  

5 7/32"

IM #2

5 3/8, 5 7/16

IM 1

5 5/16, 5 11/32

IM Trainer

5 5/16 5 5/16

IM 3

5 13/32 5 13/32

IM #4

5 15/32 5 1/2

These differences, if unaccounted for, mean that Joe's 3 rated at 429 is not exactly comparable to Bill's 429 (of the same or any other brand). The one with shorter handles will still be tougher to close ala Tom Black's handle mod. And our initial run of 429s would be tougher than any other make out there to date. There is no issue in direct competition if the same grippers are used among competitors. However, direct comparison (long distance) based solely on IP rating needs some consideration. We realized early on that the included angle and skew made a gripper easier or tougher to close. Then we realized the dogleg could mean you may or may not be able to close a gripper depending on position. Now we see there are differences, advantages or disadvantages depending on handle length. We think it is imperative, outside of direct competition using the same implements, to account for and understand the impact of configuration factors.

Similarly, realize that the configuration variations between your own grippers make a difference. As long as you take them into consideration your training effectiveness remains valid. Basically, don't overlook the obvious and don't assume IP is the sole or ultimate criteria.

The IGC may wish to consider 'equalizing' ratings of individual grippers by adjusting the IP ratings to the effective handle length. Though, what to do with a gripper with different length handles? The included angle and skew factors are also significant, but not readily 'equalized'. Likewise for the dogleg (which is most pronounced in BBs, so far).

We are holding further shipments until our grippers are revised to make them 'equally easy' (for lack of a better term). Grippers sent in for calibration and concurrent SOS orders have been calibrated and returned; the SOSs will follow when they are completed. We will absorb the additional shipping. If you have already received grippers from the first run we will be more than happy to exchange them.

As usual, we welcome any comments or input on this and other gripper related factors.

John

[Tom Black]

John,

   This is quite a bit of information, and coupling it with the dogleg observations I’m wondering just how much of a difference we are talking here.  If this is a 5 inch-pound difference then perhaps it is not that significant.  As far as handle length being a factor, could you perform some tests to determine how much of a difference we are talking.  Maybe you could make a gripper, test it, and then take the very same gripper and move or shorten with a file the handles by 1/8” and retest it.  All the factors such as the dogleg, skew and spring size would thus remain the same and you could then see for yourself what how much difference the length makes.  In light of my modified grippers I always thought that your machine would actually be able to measure the increased torque needed on a shorter difference.  If it did not, then the BB Master would have tested closer to the #2 grippers.

[Solan]

John, you are bringing in quite a lot of variables, and it now seems to me that the best way of testing crushing strength objectively - for competitions, for instance - is with a pair of handles that stay parallell as they are moved closer to each other. Do you think that is a warranted conclusion from your studies?

[Guest StoicGrip]

Solan , such grippers exist . I have one myself . The handles are parallel . It had 6 springs and I have replaced these with new and harder ones . the gripper is very comfortable to use , unlike a super gripper . Also of course you can easily add or remove springs . I think that a more updated version of this gripper using a stronger design would be an ideal way to train grip .

[Bill Piche]

Hey, Tom. It is definitely more than 5 in-lbs.    Trust me on this one.  The step John is taking is necessary.

[Guest Luke Reimer]

I don't disagree with John's decision to adjust handle length, but I think the issue is more one of convenience than necessity.  If anything, I think what makes this step necessary is precisely the sort of dismay and concern that is appearing in this thread in response to this newly addressed variable (handle length). I’m not sure that I see what the fuss is about. It seems to me that it shouldn't be too hard to work equivalencies out algebraically, since we know that the required closing force is inversely proportionate to handle length. The main thing we needed is some sort of universal numerical reference point from which to work the calculations--and thanks to John's new instrumentation, we have access to this.

I’ve thought about this some more and I think I see something that many people are missing here. It seems to me that inch-pound ratings are spring ratings, not necessarily stand-alone ratings for an entire gripping apparatus (springs plus handles). They specify spring strengths relative to each other, not the actual force required to overcome the spring (this is analogous to IronMind’s spring ratings of #T, #1, #2, #3, and #4, except with bleeding edge precision, immediate conversion-ability back into units of closing force, and options galore). I have some more thoughts on this, but first I want to back up a bit.

Naturally the unit of pounds cannot be made to say everything there is to say about grippers. We  know that stating the closing force (given in pounds) provides an incomplete picture, without also stating the handle length (given in inches) against which the balance of this force was applied (e.g. we might not know whether to envision an IM # 1 range or # 3 range gripper, theoretically,  if we were told only that this gripper took 180 pounds to close over the bathroom scale, but not whether the weight was applied right over the edge of the handle or right next to the spring.) So we cannot assign spring ratings strictly in pounds, without a reference to the handle length at which the force was applied. We need both the pounds of closing force and the inches of handle extension.

However it is interesting what happens to these values, i.e. the value in pounds and the value in inches, when we merge them into one value by way of multiplication. Suppose we have a gripper that takes 168 pounds to close when the force applied to the handles is, say, 2.375 inches from the spring end. These two values would tell us about the strength of the spring in this gripper. Now instead of saying the spring were “168 pounds at 2.375 inches,” we would say “400 inch-pounds,” for a more convenient notation. What proves that this 400 ip rating describes only the spring, and not the rest of the apparatus, is that no matter how we change the gripper in order to overcome the spring more easily, the inch-pound rating for this spring remains the same at 400. Suppose we had really long handles and were able to apply the force 23.75 inches away from the spring end. We would still get 400 inch-pounds, because although we have 10 times as many inches, here the spring would be overcome by only 1/10th as many pounds. Of course, 16.8 pounds times 23.75 comes out the same as 168 pounds times 2.375 inches.  The inch-pounds product would be the same no matter where we tried to overcome the spring, because as one factor gets bigger the other gets proportionately smaller (I realize this is an oversimplification but bear with me here).

The funny thing is, it seems to me that assessing a whole gripping apparatus strictly in inch-pounds (a spring rating) works no better than assessing its spring strictly in pounds (meaningless). When we talk about springs themselves, ip ratings are relevant, because they reference pounds to inches in a way that forms a constant for that spring. However when we talk about grippers competitively, do we really care about the strength of the spring? I think all that most of us care about is how much force it requires to make the handles touch. No one will care who closes the 400 ip gripper, if it is that special one with the 23.75 inch handles, where 16.8 pounds will do the trick. It is not the stiffness of the spring we care about, so much as the work that it takes to overcome it. Of course, knowing the spring’s ip rating is handy, if we also know the precise length of the gripper handles, because then we can work backwards (by division) to find the minimum force required on this apparatus to overcome the spring.

I realize that I haven’t been completely fair here to the “spring-centric” approach to quantifying gripper events.  I’ve been de-emphasizing inch-pound ratings  on the basis that, in theory at least, they could be rendered meaningless by sufficient variations in gripper handle length. Of course such variations do not really happen. Most grippers handles seem to be roughly the same length, (was that between 5 and 5.5 inches John?) and this simple fact would seem to turn the spring rating into the most important variable. If all our grippers had  precisely the same handle length, well, we could forget about the length variable all together. We could even forget about the actual applied force required to touch the handles, and we could compare grippers strictly on the basis of spring ratings. Maybe that wouldn’t be so bad.

Grippers handles may not be standardized quite yet, but in the meantime I can’t see any need for alarm. The hardest part is over now that PDA has found a way to get some ultra-precise numbers for any gripper spring. Now all we have to do is figure out what those numbers mean, for any two grippers when their handles are different--and that would seem to be the easy part. I just  requires a careful measurement with a ruler, and a little algebra, I think. If my handles happen to be longer than yours, then we can simply stop talking about spring ratings, and work back to the minimum closing forces required in pounds by dividing our respective ip ratings by our respective handle lengths. Alternately if someone insists on sticking with inch-pound ratings, then we can decide whose gripper gets to be considered the normal length and that person will keep his spring rating. Then the other person can adjust his spring rating by multiplying by a fraction expressing the difference between grippers (i.e. if my handles are 5.5 inches and Heath’s are 5.25 inches, and we want to consider Heath’s the normal length, then he gets to keep his 400 ip spring rating. We then figure out that my handles are 22/21 [or 1.048] of the length of Heath's. Since handle length has an inverse relationship to perceived spring strength, and my handles are longer, I have to turn my fraction over and multiply by 21/22nds [or 0.954]. If my spring rating also happened to be 400 inch-pounds, then after multiplying by this fraction, it becomes about 382 inch-pounds. Of course this would be an artificial spring rating; my spring would really be stronger than that, but it is “as though” my spring were weaker because of my odd handle length.)

There are ways to make sense of the numbers. All we need is for someone to pick one, any one. Do we insist on talking about spring ratings when the handles are different? Fine– simply adjust the spring ratings for the people with the handles deviating from the designated reference length. Do we not care about spring ratings? Fine–then divide them by all by handle length and get the minimum force in pounds for closing (of course this creates a bit of an illusion, since this theoretical minimum would be significantly below any practical one, given that no one can apply the force of all four fingers to the very end of the gripper handle). Either way we can get figures to directly compare gripper achievements.

Someone go ahead and let me know if any of this makes sense.

Cheers,

Luke

[Bill Piche]

No one is going to want to take the time to do the math.  No one is alarmed per say either.  The point was there is another variable that wasn't accounted for.  I am sure people would have been up in arms when they got a 350 SOS gripper and it was as hard as a 415 IM measured gripper due to distance from top of spring to the handle.  Everything is cool if you just stick with SOS's and progress based on THOSE IP ratings only since the grippers are being made to a specification for true quality control.  HOWEVER, that won't be the case. People will likely have both.  The effort to make the handle length more uniform overall by changing the specification is a nit.   That's all. Simple. Straightforward.  

The other thing, if John went forward with his increased spring size and kept the handles the same, you would be scratching your head when you got your 450 gripper and were a MILE off due to moment arm length.  All would be fine again if you threw out all your other grippers that were calibrated OR realized that you can't compare the IP ratings of say an IM gripper at 450 and an SOS gripper at 450.  Using Heath as an example, he would be able to rep one and not even close the other!

Again, bottom line: Better specification for the "standard".  That's all. :)

[John Szimanski]

Many of my conversations with grip enthusiasts are enlightening. Besides their intense interest in training and goal-oriented tenacity, they exhibit crystal clear thinking. Such was the conversation when Luke called yesterday. He ordered an Ivanko Super Gripper so he would have something to work with when he sent his grippers in to be calibrated. He realized a very simple and direct solution to the problem of being without his grippers while they came down across the border, were calibrated and turned around in 24 hours or less, and headed back up his way by air mail. He understood his grippers had to be calibrated so he was not working in the dark. And, of course, he wasn't about to be completely without a substitute training alternative.

I asked Luke if he had seen my post. He thought I meant the 'dogleg' post, which he had seen. It had made sense to him and he was using the dogleg to his advantage. But I had meant the 'handle length discrepancy' post, which he had not seen. I summarized the post for him. He immediately understood. He said, (paraphrasing) 'Yes, I knew there were differences but, that's no big deal. I'll measure them and use algebra to adjust for the actual handle lengths. Then I know exactly how to set up my training.' Bingo! Luke's post above also demonstrates clear thinking. And Wannagrip cuts to the chase.

Here's a spring gripper quiz that may highlight the importance all of the gripper factors. Let's 'assume' you think you apply the closing pressure at the very tips of the handles and that all grippers are seasoned and calibrated.

Q: Gripper 1 and Gripper 2 are identical in all respects except Gripper 1 is 200IP and Gripper 2 is 250IP. Which is tougher to close?

A: Gripper 2. The higher closing torque means more resistance to pull the spring closed and all other characteristics are equal, thereby canceling one another out.

Q: Gripper 1 and Gripper 2 are identical in all respects except Gripper 1 has a 15 degree skew and Gripper 2 has a 5 degree skew. Which is tougher to close?

A: Gripper 1. The wider skew means more resistance pulling the spring legs across the coil to meet and all other characteristics are equal, thereby canceling one another out.

Q: Gripper 1 and Gripper 2 are identical in all respects except Gripper 1 has a 28 degree included angle and Gripper 2 has a 34 degree included angle. Which is tougher to close?

A: Gripper 2. The wider included angle means it's harder to get your hand around, you have to close it a longer distance, and all other characteristics are equal, thereby canceling one another out.

Q: True or false? Closing a gripper in your hand is like pouring water into a glass. As the water goes straight down and conforms to the shape of the glass, so the gripper closes straight down into the fixed shape of your hand.

A: False all the way around. The gripper does change general shape due to the handles coming together. But it also decompresses (expands) at the coil, and twists around at the top where it is not confined your hand. Your hand is not a fixed shape;  it changes in three dimensions as it progresses through the close. Closing a gripper is more like pouring water into a plastic bag.

Q: Gripper 1 and Gripper 2 are identical in all respects except Gripper 1 has a 5" overall handle length (from the top of the coil to the end of each handle as measure against a true 90 degree fixture) and Gripper 2 has a 5-1/2" overall handle length. Which is tougher to close?

A: Gripper 1. The shorter overall length means the usable torque arm is shorter, and all other characteristics are equal, thereby canceling one another out. The IPs are taken exactly the same way, from precisely the same torque arm, to the point the handles touch,  therefore their full closure IPs are exactly the same. Note that Gripper 1 is tougher even though the distance is shorter. Or is it? :o

Q: Gripper 1 and Gripper 2 are identical in all respects except Gripper 1 has 2" between the handle tips and Gripper has a 3"  between the handle tips. Which is tougher to close?

A: Trick question. Such a gripper cannot exist. If the included angle, skew, and overall handle lengths are identical, the handle tips must be equidistant. Measuring the distance between tips is an invalid and misleading measurement. Thinking that closer tips alone means it is easier to wrap your hand around is misguided. It is the included angle and skew that determines how difficult it is to get your hand around and start the close. The distance between the tips is an indirect measurement of the skew, included angle, and overall handle length and tells you nothing of any value by itself. Moving the handles further up easily shortens the tip distance for a wide-angle gripper. Using handle tip distance as a criteria is akin to asking the weatherman for the temperature and he responds, 'The sky is blue.'

Q: Gripper 1 is uniform in every respect. We cut ¼" off the bottom of one handle. Is the gripper harder or easier to closer after cutting off the tip?

A: Harder. The shorter overall length of the one arm means one of the usable torque arms is shorter, the closing distance is further, and ...

Q: Gripper 1 is uniform in every respect. We cut ¼" off the bottom of one handle. Does the IP go up or down?

A: It depends on how you consider it. For the exact same closing distance before modification, the IP does not change. For the modified full closure distance, the IP will increase.  

Q: Gripper 2 is uniform in every respect except one handle is ¼" shorter than the other. Which handle has the higher IP?

A: Neither, they have the same IP. It is measured on either handle from the same torque arm until the handles touch one another. The longer overall length of the one arm means one of the usable torque arms is longer and more helpful.

Mikael asked, "Which of the inch pound ratings are correct?" The IP ratings are all correct, unchanging, and are independent of fixed handle length. Recall, the IP rating is taken at a standardized torque arm of 2-3/8". This is done so that every measurement is taken uniformly for every single gripper. Because of the way the gripper is mounted in the calibration press and the way the press closes, the degree of difficulty added by the skew and the included angle are included in the IP rating. We don't know, specify, or try to measure the exact degree of difficulty imposed by the angles since there is no point to do so. However, it is sensible to realize the included angles of a 25-32 degree IM and a 30-37 degree BB is a significant difference and means the grippers are not identically equivalent even if all other factors are equal.

Solan has brought up two very valid points. The first, that there are a lot of factors involved. Yes, there are far more factors than anyone was aware of until grip meister rankings became popular. Unfortunately the original gripper suppliers sold us out by invalid ratings, improper labeling, willfully changed components, (now we find) the absence of any concern for quality control. So, no, grippers in general are not good tools for long-distance comparisons. A specific selection of properly rated grippers with appropriate IP spreads is perfectly suitable to use for a competition. But don't lapse into relying solely on IP rating to indicate toughness unless you are using only SOS grippers. And using the same grippers at other events would provide equal rankings. Using grippers as an across-the-board ranking tool still does not hold water. Seasoning and calibration of sub-par grippers does not make up for their defects. It simply makes them better training tools. Quality grippers that are seasoned and calibrated are more reasonable. But using different grippers for rankings will always be flawed.

IP ratings for uniformly produced grippers provide a level rating system. The PDA IP calibrations are a standardized measurement taken identically on all grippers. Where you have been sold poorly controlled grippers from other suppliers you will have to estimate the effective tip IP based on your shortest effective handle as Luke immediately realized.

Are the SOS Super Dutys any good? Here's an email received this morning:

"I have received the class II and III SOS grippers this week, they're

great. I know I have a standing order in for 2 each of the class T, I

and IV(6 total grippers). I was wondering when they would be

available? Thanks for another great product. Paul L. M."

Paul received four Super Dutys nicely spread in increments from 264 to 400 IP. He was not burdened by other inconsistent brands. And now that we have the 'Super Duty dilemma', I have a pretty good idea of what Paul's reaction will be.

At the same moment we woke up to the poor quality control on the handle length of existing grippers, we realized we had inadvertently created more difficult grippers with generally shorter handles. This happened because we focused on correcting another gripper flaw we had found - the distance the top of the handle was from the coil. Our effective handle lengths were much more consistent than the other grippers, but they are tougher to close than other grippers with similar IPs but inconsistent and uncontrolled variables as noted in the quiz. Warren Tetting made some (now classic) Super Duty grippers. We inadvertently created our own and would prefer to have the few of them circulated back.

We were very successful at making a run of the most consistent grippers yet, but the overall handle length was our oversight. We neglected to pass them by our Product Development Director and his team. (For clarification, I am neither the Director, nor on the team, nor did I select the title. I am merely the equipment geek.) And, we delivered exactly what was promised by spec. Still, we will be pleased to take fully compensated returns plus 10% for SOS Super Duty grippers already shipped as long as:

1. They are not damaged and in original condition.

2. They are returned with the original documentation.

3. They are returned by the same method of shipping as originally provided.

4. Ancillary expenses such as duty are documented by receipt.

5. They are documented in transit by midnight EST Tuesday  10/30/01.

This should be an easy decision to make and the conditions are more than reasonable. To be clear, 'fully compensated returns plus 10%' means, a full refund for your original expenses, plus your equivalent return shipping, plus duty if applicable,  plus 10% of the total of the previous items. This offer applies effective immediately to all recipients and expires as indicated without exception.

Regarding our course change and pathforward:

1. New sample length grippers have already been made and are enroute for evaluation by our Product Development Director.

2. We intend to settle on a rational and effective overall handle length.

3. We will also look at any other variables we may be able to control.

4. We will continue doing whatever it takes to produce the highest quality, most uniform, cost-effective gripper available.

5. We will maintain course to provide all the wire sizes necessary to effectively encompass the entire range of known gripper strengths and beyond.

6. We will not spend time trying to explain, correct, calculate, rationalize, or otherwise consider the defects of other brands of grippers other than to identify and address them as potential ways to improve SOS grippers.

As has been mentioned before, PDA developed the Ironhorse Atlas grip machine as a means to train intensely and successfully for gripper achievement. And it worked, helping to produce a (nagging) current COC. Upon completion of the Atlas we documented performance electronically. The machine provided a stable, unchanging basis of comparison between users wherever a machine was delivered. Then we started checking grippers to validate the machine and nothing added up. One by one defects in the existing grippers surfaced. Less than three weeks before we announced the SOS grippers, Steve had asked me if we would ever get into our own grippers. I had told him, 'No, they have too many problems and inconsistencies.' Yet, the logistics fell into place, we thought we had identified all of the variables, and felt a tight spec and quality control would solve all of the problems. And, all of that does apply to our own grippers. However, nothing we, or anyone else,  can do to correct or make up for what others do. We can make the most consistently uniform calibrated grippers. We cannot account for or correct the work of others who have never made two identical grippers.

Because of all of these factors Solan raises his second point - that a machine may be the most appropriate competitive device. However, is using a parallel grip (guillotine-type) machine logical? We recognize that guillotines can be cost effective. But they have never been produced by tight tolerances. If springs are used you are back in the same morass as the torsion spring grippers. Straightforward plate loading cuts through the mess. Guillotines have inherent frictional properties that will vary uncontrollably (over the sliding surfaces) once the machines are distributed. Guillotines have been used as adjunct training for grippers. Yet we realized long ago they were not specific for direct gripper training. They are not easily portable. Not everyone can afford a machine. Everyone can afford a gripper. And, the grippers offer an inexpensive training tool to mimic a consistent machine that most closely mimics the grippers. Until recently the Atlas came closest and provided documented and validated performance. The Ironhorse Gripanator is evolving to provide the closest contender.

The second Gripanator prototype is nearing completion for evaluation by the Director and team. The final closed position of the handles is exactly the same as a gripper. The adjustable included angle and several other goals fell into place. We should warn you - the concept rendering we had posted on our site (referencing the GenII) was just that - a concept.  It was intended to convey the key features, and did. However, you have never seen anything like it, except perhaps, in a dream after you watched Star Wars. Regarding competitions, the Gripanator equalizes many factors including starting position. Cheating can be clearly identified and elimination due to cheating is self determined.

The Atlas took grip machines to the next level. The Gripanator goes far beyond. Kevin already intends to use his for competitions. We expect competition Gripanators to be comfortably accepted wherever they are used. And, inexpensive portable grippers will be effective training aids. Even the crappy ones.

John