80mm CoC #3 153rgc

[Vinnie]

11 minutes ago, Vinnie said:

I don't understand this part quoted above, which is making me have trouble following the rest.  I mean, I got a 5 in AP physics, so I should be capable of understanding -- but it was 1986, so I think I probably forgot most of it and probably need a reminder (I'm a lawyer now and I don't use math much).

First question is, are you referencing g, the constant acceleration of gravity?  You didn't say so in that sentence, but then later you substitute the constant and talk about using grippers on earth, so I think it is what you mean.  But how does gravity have anything to do with the questions being examined about closing the gripper?  The resistance of the spring would be (at least substantially) the same in any other acceleration frame, and we are interested only in the close, not in whether the entire gripper and you are being pulled toward a massive object at the same time.  In other words, I would think a gripper would be just as easy or hard to close in free fall, or on Mars, wouldn't it?  I mean with negligible difference that we aren't trying to account for, anyway.

I am also confused by the integral.  If we are simplifying to make the assumption that the distance the gripper is closed is the chord rather than the arc, and that the distance covered when force is applied will correlate linearly with the force applied until force equal to RGC closes it fully, then why do we need the area between the handles?  Wouldn't applying half the RGC of the gripper just close it half way?

I am not asking these questions to suggest you are wrong about anything.  I am assuming I am misunderstanding something, because I am rusty, and am hoping to understand it.

I might be starting to understand - including g is because F=ma, and on Matt's rating device, the pound rating is the mass that in earth gravity closes the gripper.  So it isn't that changing g would change what your hand has to do, it is just that g was part of figuring out the RGC in the first place, right?  I was imagining a hand closing the gripper and forgetting that RGC - which we like to speak of as "pounds" - is computed with masses acting in earth gravity.

It might be harder for me to figure out the integral.  I only got a 4 in AP Calc lol.

[matek]

46 minutes ago, Vinnie said:

First question is, are you referencing g, the constant acceleration of gravity?  You didn't say so in that sentence, but then later you substitute the constant and talk about using grippers on earth, so I think it is what you mean.  But how does gravity have anything to do with the questions being examined about closing the gripper?  The resistance of the spring would be (at least substantially) the same in any other acceleration frame, and we are interested only in the close, not in whether the entire gripper and you are being pulled toward a massive object at the same time.  In other words, I would think a gripper would be just as easy or hard to close in free fall, or on Mars, wouldn't it?  I mean with negligible difference that we aren't trying to account for, anyway.

You are right. The gripper itself doesn't change of course (spring constant would be the same), and if we're not using weights like in RGC it essentially doesn't matter (maybe the gripper's weight would feel heavier/lighter of course ). And it's the same for all grippers, a constant, but the reason I included it is because otherwise, any calculation I make has an arbitrary unit, and this (at least if we need it in Newtons):

28 minutes ago, Vinnie said:

So it isn't that changing g would change what your hand has to do, it is just that g was part of figuring out the RGC in the first place, right?

46 minutes ago, Vinnie said:

I am also confused by the integral.  If we are simplifying to make the assumption that the distance the gripper is closed is the chord rather than the arc, and that the distance covered when force is applied will correlate linearly with the force applied until force equal to RGC closes it fully, then why do we need the area between the handles?  Wouldn't applying half the RGC of the gripper just close it half way?

Sorry if I wasn't clear, the triangle is not about the area between the handles. Imagine a simple 2d coordinate system where your x-axis is the spread and the y-axis is Force. Because we assume that the force increases linearly from 0 to the measured RGC value, we have a straight line. And for Work, we need the integral of force up to a certain spread; hence we have a right angle triangle. 

Btw thanks for the questions. The last time I did a calculation like this about levering, not many people cared, including the person who asked the question 

Edited October 13, 2023 by matek

[Cannon]

1 hour ago, Vinnie said:

One thing that would be interesting, whatever the answers to these questions are, would be if Matt did an experiment and took some grippers of different spreads and measured how much weight closed the handles to ccs, 38mm, and 20mm, and fully closed (RGC).  If he's measuring by ruler and eyeball it won't be perfect, but it might be enough to give a sense of how linear this is (or isn't).

I literally did this last night! My daughter has to do a project for an IB Math Analysis class and she chose to do this type of gripper analysis. The math wasn’t quite hard enough so she tweeked the experiment a little in terms of using the data. 

But to collect the data last night we took 178 HG350 and 178 IM3.5 and also 149 HG300 and 149 IM3 and rated them every 5 mm from open to close.

I asked her for the data and will report back. 

[matek]

3 minutes ago, Cannon said:

I literally did this last night! My daughter has to do a project for an IB Math Analysis class and she chose to do this type of gripper analysis. The math wasn’t quite hard enough so she tweeked the experiment a little in terms of using the data. 

But to collect the data last night we took 178 HG350 and 178 IM3.5 and also 149 HG300 and 149 IM3 and rated them every 5 mm from open to close.

I asked her for the data and will report back. 

That's great!

I will try to do some curve fitting and make a new calculation for Work when I have time

Edited October 13, 2023 by matek

[Cannon]

I forgot about this.

[C8Myotome]

Yep looks pretty accurate.

For reference yesterday I closed a 173 GG6 left-handed.

My actual left-handed max is 158 on a standard cobalt.

So on a grip genie I instantly went 15 lbs heavier above my all time max, and it was easier than my true max too. I actually failed my true max yesterday and only did 155 left handed, so on GG I went 18 lbs heavier than what I could actually do that day.

I don't really see the training benefit when it is that easy, and it feels like even at parallel you're resting/taking a break. Might as well hold a barbell at that point

Sure, they're fun, and make it look like you're stronger than you really are, but that's it really

Edited October 14, 2023 by C8Myotome

[Cannon]

30 minutes ago, C8Myotome said:

For reference yesterday I closed a 173 GG6 left-handed.

My actual left-handed max is 158 on a standard cobalt.

Have you worked on your lefty set? Sounds like it’s lagging. I’m far less coordinated on that side as well. 

[C8Myotome]

9 minutes ago, Cannon said:

Have you worked on your lefty set? Sounds like it’s lagging. I’m far less coordinated on that side as well. 

Yes of course, my left set is just as good as my right, but strength overall not as strong as my right not due to setting but overall strength as shown by rep work and dyno etc

On my right hand I did the GG6 173 for 3 reps, while my right hand has only done a 173 coc 3.5 for 1 rep from about 30 mm

They're just easier lol

Edited October 14, 2023 by C8Myotome

[Cannon]

2 minutes ago, C8Myotome said:

They're just easier lol

Yeah, lolz

[Mashmonster268]

As has been pointed out, this isn't rocket science. Which is also comical because one of the guys pointing it out couldn't figure out to stand on some boxes to increase range of motion, but the same guy will go on and on with chalkboard musings (Grippenheimer when it comes to grippers, lol) about how he apparently thinks dedicated gripper guys are unaware that a narrower gripper with the same RGC as a wider gripper will be easier. 

[C8Myotome]

56 minutes ago, Mashmonster268 said:

As has been pointed out, this isn't rocket science. Which is also comical because one of the guys pointing it out couldn't figure out to stand on some boxes to increase range of motion, but the same guy will go on and on with chalkboard musings (Grippenheimer when it comes to grippers, lol) about how he apparently thinks dedicated gripper guys are unaware that a narrower gripper with the same RGC as a wider gripper will be easier. 

I enjoy how salty you are that you asked me for gripper tips right before I certified the 3 (something you have not done), then flipped out after I denied your Facebook friend request due to what you had to say about my crushed to official ironmind crushed to dust certification

I'm over here getting stronger collecting gripper certs you will never achieve and you're still here being salty for almost the last year over me telling you that you permanently burned a bridge with me

It's pretty entertaining to say the least that I'm training for the 3.5 and GHP9 certs and you're mad about me following ironmind's rules

[Cannon]

Everybody got a swing. Please refrain from personal jabs. Thanks guys. 

[slazbob]

It just means certain parts of your hand isn’t as strong. To be on the side of it being useless, I can’t wrap my head around. If it’s the close power that matters, then they all work. 
 

if setting a wider gripper is putting more force on an area not up to the level, it’s going to make it harder haha. 
 

but if someone is attempting an 178 3.5 at 78mm and set it to 50, it’s only really 117 rgc in the hand at that point…according to the chart. If that’s the case, and it’s making it harder than the rgc close indicates, use a Vulcan to build up the wide strength. 
gueess that’s why Iron Mind always said to use full range in training and partials to change things up. 

i know everyone is aware of this. it’s hard to spend time in the weak areas because we want to have that progress. And to be honest, more progress seems to be made with a shorter stroke…but it’s a hider of our weakness. If all grippers were parallel, what a different world it would be, eh?

[Kevin Gripz]

On 10/3/2023 at 11:47 PM, dubyagrip said:

Let me borrow it. I want to TNS it.

I will send it to you with $10 to send it back if you DM me on Instagram

[matek]

8 hours ago, Cannon said:

I forgot about this.

Thank you. I hope your daughter's project went well.

Looks like the linear assumption is very accurate (at least for these grippers), so the calculation I did before for Work is ok.
Here it is visually with the coefficient of determination if somebody is interested. 

Edit: one of the titles wasn't correct, I changed that

 

 

Edited October 15, 2023 by matek

[martincerven]

Doesn't also area under curve matter? You travel more distance with wider gripper, For example with 149lbs grippers for 73mm IM3 the AOC is 5198.3 and for HG 300 is 4148.0  (Jouls?). I think intuitively if you have choked gripper you expend less energy total the more you choke it, so wider grippers would require more total energy even if final RGC is the same. 

 

[martincerven]

It has been a while since I've done any physics, maybe someone ( like @Jared P ) can make some list of good resources? I found this amazing youtube playlist about torsion springs that I watched for an hour There should be lot of theory about torsion springs, although I would say grippers are an interesting edge case

 

[matek]

29 minutes ago, martincerven said:

Doesn't also area under curve matter? You travel more distance with wider gripper, For example with 149lbs grippers for 73mm IM3 the AOC is 5198.3 and for HG 300 is 4148.0  (Jouls?). I think intuitively if you have choked gripper you expend less energy total the more you choke it, so wider grippers would require more total energy even if final RGC is the same. 

 

See my post on the previous page. This last curve fitting was only to check if the assumption "force increases linearly with displacement" is correct (at least with these 4 grippers, it seems to be correct). 

[martincerven]

1 hour ago, matek said:

See my post on the previous page. This last curve fitting was only to check if the assumption "force increases linearly with displacement" is correct (at least with these 4 grippers, it seems to be correct). 

I see.

Using the equation I got:

~24.23 J for the IM3
~19.56 J for HG300

and computing area under the curve with @Cannon data I got:

~23.131 J for the IM3
~18.46 J for HG300

 

so quite close results!

 

[martincerven]

On 10/10/2023 at 3:44 PM, matek said:

To illustrate the difference let's calculate Work. 
Work is a force causing an object to have a displacement. W = Fd. 
With RGC, we are measuring the force required to overcome the resistance of the spring. So F = RGC * g. 
The handles do not travel in a straight line, but it would make it unnecessarily complicated if we had to calculate the arc length for displacement. So we can just use the chord length -what we call "spread"- as a rough approximation. 

Of course, the problem is that we do not apply that much force from the very beginning. Without going into spring geometry and materials, let's assume that the increases linearly from 0 to the measure RGC value (as Derek did). 
The slope m would be (RGC * g)/spread, and F exerted when it's closed by a distance x is (RGC * g * x)/spread (same calculation Derek did, just including g). 
Work here is the integral of force with respect to displacement. Since we assume that force increases linearly with displacement, we just have a triangle under the curve (if we don't have the linear assumption -if we would take into consideration torsion spring constant for example-, we would have a "real" integral). The area of a right triangle: 1/2 x base x height, where in our case base is actually our displacement x, and the height is the force at the displacement. 
W = 1/2 * x * [(RGC * g * x)/spread], and if we simplify and just use the constant 9.81 as acceleration due to gravity (because we use grippers on Earth):
W = (RGC * 9.81 * x^2)/(2spread)

Let's calculate it for two hypothetical grippers (keep in mind that we need to use the correct units to get the work W in Joules):
RGC 150, 65mm spread, fully closed:
W = (68.04kg * 9.81m/s^2 * 0.00423m) / 0.13m = 21.72J
RGC 150, 80mm spread, fully closed:
W = (68.04kg * 9.81m/s^2 * 0.0064m) / 0.16m = 26.7J 
RGC 150, 65mm spread, set to 38mm block set:
W = (68.04kg * 9.81m/s^2 * 0.00073m) / 0.13m = 3.748J
RGC 150, 80mm spread, set to 38mm block set:
W = (68.04kg * 9.81m/s^2 * 0.00176m) / 0.16m = 7.342J
RGC 150, 65mm spread, set to 20mm block set:
W = (68.04kg * 9.81m/s^2 * 0.00203m) / 0.13m = 10.423J
RGC 150, 80mm spread, set to 20mm block set:
W = (68.04kg * 9.81m/s^2 * 0.0036m) / 0.16m = 15.0181J

@C8Myotome This captures in a single number what you also explained.

@Cannon This is what you meant by " the narrow gripper doesn't feel easier because the pounds at close isn't actually 100, but rather it feels easier because it was less total work to get to closed which ratings do not capture well". 

I think this video explains @matek's computation and here is my math (its python) - if somebody wants to check it

grip_work.txt

[matek]

24 minutes ago, martincerven said:

I see.

Using the equation I got:

~24.23 J for the IM3
~19.56 J for HG300

and computing area under the curve with @Cannon data I got:

~23.131 J for the IM3
~18.46 J for HG300

 

so quite close results!

 

Cool! Yes, it should be very close!

[Cannon]

@Mashmonster268 @C8Myotome

I hid your last posts. Take it to PM where you can block the other if desired. Also, knock it off.  

[C8Myotome]

So I can't even begin to think how to implement this but I think overall an even more accurate way to describe a gripper using formulas would be to not use the inside of the handles to capture spread/distance to close

Instead rather if the outside of the handles were used as the to calculate starting and finishing points of a close, this would capture both the elements of not only handle thickness but also if a gripper is filed. This would account for any extra difficulty of setting/holding a gripper with wider handles, and also note that it wouldn't be closed as deep.

This would also account for how deeply closed a gripper will be, such as in grip genie or a very filed gripper

Just to go back to grippers where we used 75 mm spread as an example, let's say CoC with 19 mm handles...so 75+19+19 = would be a 113 mm actual spread that accounts for handle thickness, that travels to a "close thickness" (?) of 38 mm, since 38 mm is the distance of how "deep" the close is of 2 19 mm handles.

You could then follow whatever formula works to capture this to show WHERE in the spread the extra difficulty for a particular gripper is..like ok we filed it, now the finishing position of our gripper on this graph is 38 - 5 = a 33 mm "closed position"

You could use this to show why grip genie is easier than heavy grips because even with same spring spread, grip genie still has 2 mm less that you have to initially hold, making them easier to set and so on

This could be really valuable to show why grippers with different handle sizes with or without filing are harder by accounting for different setting positions and final close positions required

We could show that the spread occurs in a more open handed position or a more closed handed position to show why 175 RGC will feel different with 20 mm, 19 mm, and 18 mm handles, or why 175 RGC would feel different on a 165 RGC with 19 mm handles with 5 mm filed off that resulted in 175 RGC etc...basically if we used an outside the handle spread rather than an inside the handle spread, we could capture this very important data of where the sweep actually occurs, rather than currently just saying the sweep is how much the spread is. This method would capture the true change in shape of the gripper from open to close which the hand has to accommodate. Currently we just say 75 mm to 0 mm which only accounts for space between the handles and not what is going on on the outside of the handles  @Cannon @matek

Edited October 18, 2023 by C8Myotome

[martincerven]

48 minutes ago, C8Myotome said:

So I can't even begin to think how to implement this but I think overall an even more accurate way to describe a gripper using formulas would be to not use the inside of the handles to capture spread/distance to close

Instead rather if the outside of the handles were used as the to calculate starting and finishing points of a close, this would capture both the elements of not only handle thickness but also if a gripper is filed. This would account for any extra difficulty of setting/holding a gripper with wider handles, and also note that it wouldn't be closed as deep.

This would also account for how deeply closed a gripper will be, such as in grip genie or a very filed gripper

Just to go back to grippers where we used 75 mm spread as an example, let's say CoC with 19 mm handles...so 75+19+19 = would be a 113 mm actual spread that accounts for handle thickness, that travels to a "close thickness" (?) of 38 mm, since 38 mm is the distance of how "deep" the close is of 2 19 mm handles.

You could then follow whatever formula works to capture this to show WHERE in the spread the extra difficulty for a particular gripper is..like ok we filed it, now the finishing position of our gripper on this graph is 38 - 5 = a 33 mm "closed position"

You could use this to show why grip genie is easier than heavy grips because even with same spring spread, grip genie still has 2 mm less that you have to initially hold, making them easier to set and so on

This could be really valuable to show why grippers with different handle sizes with or without filing are harder by accounting for different setting positions and final close positions required

We could show that the spread occurs in a more open handed position or a more closed handed position to show why 175 RGC will feel different with 20 mm, 19 mm, and 18 mm handles, or why 175 RGC would feel different on a 165 RGC with 19 mm handles with 5 mm filed off that resulted in 175 RGC etc...basically if we used an outside the handle spread rather than an inside the handle spread, we could capture this very important data of where the sweep actually occurs, rather than currently just saying the sweep is how much the spread is. This method would capture the true change in shape of the gripper from open to close which the hand has to accommodate. Currently we just say 75 mm to 0 mm which only accounts for space between the handles and not what is going on on the outside of the handles  @Cannon @matek

What we talked before with @matek , the spread+RGC captures the “difficulty” of a gripper completely, you can also calculate effort of a particular set, like 20mm block or 38mm block, and compare different grippers. I think I could make a simple website that would make all the calculations. I could also make the video (since I like making videos) how does that work, and demonstrate it since I got few rated grippers myself, and I have HG250 112 and PT with 113 rating and different spreads that could serve as an example. I think the RGC measurement should stay as it is and we should not invent new needless stuff since from @Cannon data it seems that with combination with spread it basically describes the “difficulty” of a gripper (almost) perfectly. 

[C8Myotome]

6 minutes ago, martincerven said:

What we talked before with @matek , the spread+RGC captures the “difficulty” of a gripper completely, you can also calculate effort of a particular set, like 20mm block or 38mm block, and compare different grippers. I think I could make a simple website that would make all the calculations. I could also make the video (since I like making videos) how does that work, and demonstrate it since I got few rated grippers myself, and I have HG250 112 and PT with 113 rating and different spreads that could serve as an example. I think the RGC measurement should stay as it is and we should not invent new needless stuff since from @Cannon data it seems that with combination with spread it basically describes the “difficulty” of a gripper (almost) perfectly. 

No I'm going past what we talked about and probably into unnecessary territory, there is much more to difficulty than just rgc and just spread...with those factors the same an 18 or 20 mm handle will have a difference in difficulty depending on what people are better at.

There are people way stronger than me that cannot close a double-filed coc 3 like I can because they cannot close as deep as I can..I'm just saying if you really wanted to describe WHERE in space and time the difficulty of each gripper comes from then the handle width of both handles and the final close position is very important

Just for an obnoxious example, something that is only 100 rgc that had 25 mm handles would be super difficult because you would be holding 50 mm at the final close which is quite wide

Just focusing on internal handle spread and rgc ignores all these factors

But I agree if your job is just to sell grippers or rated grippers then this is going way into the deep end of information...but are still factors that exist and are important