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Future Of Rating Grippers!


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#1 OFFLINE   Mighty Joe

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Posted 14 July 2013 - 03:04 PM

Wanted to share with everyone something I've been experimenting with since December of

last year. I received a digital crane scale as a Christmas gift and originally I had planned on making

a arm wrestling type dyno to measure one's pulling forces from various angles but instead I tried

a NEW method for rating grippers. I've attached some pics of the setup below so you can get an idea

of what I've come up with.

 

A little background first. Ever since I had a RGC device I instantly started trying to think of a better more

efficient and accurate method to accomplish rating grippers without all the manual labor, back aches, fumbling with

a jack to raise the weight up and down, etc. and in the process have a repeatable, accurate method that can be

consistently used by anyone to come to the same conclusions on rating grippers. Well! I have done just that and I've

done numerous tests to get all the bumps out of the method and I can assure you this is by far the most accurate

method I have personally found to date. You never have to lift a weight plate and the speed and accuracy at which you can rate a lot of grippers is stunning! My last test was completed today before I decided to go public with my idea and I can envision this method being the future of rating grippers. Yes! You'll have to shell out the money for a quality dynamometer to perform this method but the cost is well worth it! Today I rated 7 very strong grippers and seen what kind of time I was looking at and I completed the process in under 30 minutes and some of that time was going in the house for a drink. I wanted to video this process today as well but the humidity was overwhelming and I didn't want to put my camera gear at risk to condensation from fogging.

 

The dynamometer I now use to rate grippers is a Chatillion CCR 440 with an accuracy of +/- 0.2% at full scale. These are classified as crane scales and are very reliable and accurate. I have a Certificate of Calibration with this dyno and it has worked flawlessly! In conjunction with this dyno I use a hand ratchet strap system to ratchet down the gripper handle till they touch and then press the hold function to record the reading. It also has a tare function to zero the meter in certain circumstances which is a bonus for any dyno/scales. I tested and retested this dyno with another certified scale I use to weigh weight plates and they both coincide precisely!

 

The tests I performed was to take "x" amount of sample grippers (now 20) that was rated the conventional method and compare these findings to the findings of the Digital Dyno Method. Every single sample gripper came out within a pound and less. Only one gripper was at the one pound mark. All the other samples were within ounces. These tests confirmed several things. 1) It verified that my previous method was accurate and apparently done correctly despite others saying my results were always low. 2) results/findings are repeatable in comparison to the current method of too many people

coming up with different ratings for the same gripper.

 

The purpose of me sharing this information and idea is to hopefully spur others that take accuracy and repeatability 

of rating grippers seriously and take the leap and perhaps give this method a try. If we as a community don't take our sport serious and apply science to our standards then no one else will take us serious either.

 

Lastly, I always cringed when someone would ask me what RGC stood for and I just hated to use the word red neck

when trying to describe a process that was intended to be an accurate method for rating grippers. Just didn't sound right to me! I will now tell others when they ask that I use the DDM (Digital Dyno Method) to rate grippers. Sounds better than

a Red Neck Gripper Calibrator in my view. Before anyone says I'm making fun of or poking at the RGC method, I'm not!!! I'm saying that there is now a better way! RGC is all we've had to work with and we did the best we could. I can't speak for anyone else but I'm always thinking outside the box and I constantly look for ways to improve whatever it is I set out to accomplish. No more back aches for me when I rate grippers! :)  No more dreading to rate a monster gripper because of tossing around a bunch of heavy ass weight plates and hoping that the whole mess doesn't fall over and kill somebody. :(

 

Any input or further suggestions is appreciated! I always welcome criticism as long as it's positive in nature

and is intended to make things better. Bring it on!!!

 

Thanks!!!

 

Here's a list of the BIG grippers I rated using the DDM today along with the results in pounds:

 

GHP 8 = 173.4, GHP 9 = 214.6, AG 5 band = 208.2, Tetting WC = 277.2, Shorty Elite = 196.6, Shorty SE = 218.8

and a Shorty GE = 223.0 Note: Shorty's are a set of grippers I had custom made by Warren Tetting with 3-1/4" handle length instead of the conventional 3-3/4" length. These are perfect no-set grippers BTW!

 

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#2 OFFLINE   Electron

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Posted 14 July 2013 - 03:27 PM

Very cool!
Definitely a faster, more reliable way to rate.
Liking the decision that you didn't shorten it to DDR (Digital Dyno Rating... also Dance Dance Revolution)
Although the dyno here is pretty expensive, hope this catches on.
As a perk, weights can be measured accurately like this too!

#3 OFFLINE   Josh O'Dell

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Posted 14 July 2013 - 03:45 PM

Very nice ! I just started rating my grippers rgc, This looks alot easier and accurate.

#4 OFFLINE   mudhutmasher

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Posted 14 July 2013 - 03:53 PM

I dig it.

Edit: would prolly work well with steel calibrations as well.

Edited by mudhutmasher, 14 July 2013 - 03:54 PM.

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#5 OFFLINE   Mighty Joe

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Posted 14 July 2013 - 04:04 PM

I dig it.

Edit: would prolly work well with steel calibrations as well.

Good thinking Tommy! I believe it would work well except for the fact that you'd have to get a higher rated

dyno because this model goes to 440 lbs/200kg.



#6 OFFLINE   climber511

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Posted 14 July 2013 - 05:19 PM

The future of gripper rating is going to mean a graph of gripper strength done every mm etc to create a graph showing force needed throughout the close from start to finish.  I have no idea what it will take to do that but closing force number alone is not enough information to tell much about the feel in the hand of various grippers. 


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#7 OFFLINE   bubba29

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Posted 14 July 2013 - 05:30 PM

The future of gripper rating is going to mean a graph of gripper strength done every mm etc to create a graph showing force needed throughout the close from start to finish.  I have no idea what it will take to do that but closing force number alone is not enough information to tell much about the feel in the hand of various grippers. 


I agree with Joe's summary...a much more repeatable and efficient procedure.. I also agree that grippers have different resistances throughout their ROM. Would be great to know that info also.

#8 OFFLINE   bwwm

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Posted 14 July 2013 - 11:20 PM

Aaron's been RGC'ing grippers with a force meter for over a year, maybe longer.  I have used his setup at his place, and you do have to be careful about how you tar the device, before you start to leverage the gripper closed.  There's a couple of ways you could record the position of the handle along with the force applied at that current position.  At which point the question becomes, do you want to rank grippers by max force at close, or integrate the total force curve over the starting position at set through close?  I'm sure there's a discussion and experimentation to be had there as well, but it comes down to how complicated does one want to make these things?  For a comp maybe, but for training, I think it's a bit much, even if one automated the RGC procedure.



#9 ONLINE   Gary Gray

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Posted 15 July 2013 - 05:00 AM

Joe,

 

     Very interesting Article.

     One Question I have had for a long time (although a little off-toptic).  Where do you place the strap on the gripper handle -  at the very end of the gripper handle or at the middle of the gripper handle?

     Lee Hayward on behalf of HG said HG rates their grippers at the middle of the gripper handle.  ( the Cannon wedsite also rates the CofC much lower than Ironmind.  Does Ironmind also rate the CofC at the middle of the gripper handle?) 

     It would  nice if all gripper companies would rate their grippers the same way.



#10 OFFLINE   Mighty Joe

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Posted 15 July 2013 - 05:07 AM

Aaron's been RGC'ing grippers with a force meter for over a year, maybe longer.  I have used his setup at his place, and you do have to be careful about how you tar the device, before you start to leverage the gripper closed.  There's a couple of ways you could record the position of the handle along with the force applied at that current position.  At which point the question becomes, do you want to rank grippers by max force at close, or integrate the total force curve over the starting position at set through close?  I'm sure there's a discussion and experimentation to be had there as well, but it comes down to how complicated does one want to make these things?  For a comp maybe, but for training, I think it's a bit much, even if one automated the RGC procedure.

I would love to see Aaron's setup! Yes! You have to aware of numerous variables when setting up the gripper and

as you ratchet down the handle. This is why I used a power rack with the attachment method I used. Simply screwing a bolt into the floor

as an anchor is not optimal due to the angles involved as you ratchet the handle down. Has to be adjustable in my estimation.

 

Lastly, I've never heard anyone at a grip comp say they wonder what the strength curve was of that gripper they just closed.

You must admit that the majority care about max force to close the gripper.

 

Thanks for the input!!!



#11 OFFLINE   climber511

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Posted 15 July 2013 - 05:46 AM

Lastly, I've never heard anyone at a grip comp say they wonder what the strength curve was of that gripper they just closed. You must admit that the majority care about max force to close the gripper.

 

You really need to go to more comps and close more rated grippers with different numbers then.  At comps in the past and then at Nationals this year (and several of us since then) have had (and are currently having) discussions about what grippers RGC and how they close.- with lower numbers feeling harder and higher numbers feeling easier at times.  There is much more to the story than just the final closing force.  When Dave and Greg cme up with the RGC it wasn't really meant to be used quite the way we have morphed it into over the years.  It was called Redneck for a reason..  It does give a whole lot better idea of resistance than #1 - #2 - SM - GM etc and at the moment its the best we have - but we do need a better mousetrap so to speak if we wish to really know the whole story.  Joe - your way is certainly easier and quicker and I wish I had had one when I was doing all the ratings I did - it's probably as accurate but no more accurate overall though than the results obtained by those of us who have done hundreds of grippers before and have a good system developed like Matt, Eric, and Aaron for example.  Honestly for training you are correect but for National level competition and promoters who really care - we need better. 


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#12 OFFLINE   Electron

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Posted 15 July 2013 - 07:16 AM

Chris, this method will easily make that graph you speak of.
All that needs to be done is to pull the handles down slowly and the force throughout is always displayed on the reading.
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#13 OFFLINE   bubba29

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Posted 15 July 2013 - 08:08 AM

 

Lastly, I've never heard anyone at a grip comp say they wonder what the strength curve was of that gripper they just closed. You must admit that the majority care about max force to close the gripper.

 

You really need to go to more comps and close more rated grippers with different numbers then.  At comps in the past and then at Nationals this year (and several of us since then) have had (and are currently having) discussions about what grippers RGC and how they close.- with lower numbers feeling harder and higher numbers feeling easier at times.  There is much more to the story than just the final closing force.  When Dave and Greg cme up with the RGC it wasn't really meant to be used quite the way we have morphed it into over the years.  It was called Redneck for a reason..  It does give a whole lot better idea of resistance than #1 - #2 - SM - GM etc and at the moment its the best we have - but we do need a better mousetrap so to speak if we wish to really know the whole story.  Joe - your way is certainly easier and quicker and I wish I had had one when I was doing all the ratings I did - it's probably as accurate but no more accurate overall though than the results obtained by those of us who have done hundreds of grippers before and have a good system developed like Matt, Eric, and Aaron for example.  Honestly for training you are correect but for National level competition and promoters who really care - we need better. 

 

 

another thing to consider is the variability of crushing strength of the hand throughout it's range of motion.  when we know that paired with the actually resistance needed to move a gripper throughout it's various degrees of motion, we can get a real sense of which grippers are harder to close.

 

for instance, i'd like to know why GHP grippers seem harder to close than similarly rated CoC grippers.  is it only because a slightly wider spread?  or is there more to it?



#14 OFFLINE   bwwm

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Posted 15 July 2013 - 08:53 AM

Chris, this method will easily make that graph you speak of.
All that needs to be done is to pull the handles down slowly and the force throughout is always displayed on the reading.

 

Well, it's a bit more involved than that.  One has to output the force as a signal to a data acquisition card, and then come up with a way to syncronously record close angle.  It can be done It's just the time & expense.  There's other ways one could estimate close angle as well, and sync that up with the force measurements.  



#15 OFFLINE   acorn

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Posted 15 July 2013 - 09:40 AM

 

Chris, this method will easily make that graph you speak of.
All that needs to be done is to pull the handles down slowly and the force throughout is always displayed on the reading.

 

Well, it's a bit more involved than that.  One has to output the force as a signal to a data acquisition card, and then come up with a way to syncronously record close angle.  It can be done It's just the time & expense.  There's other ways one could estimate close angle as well, and sync that up with the force measurements.  

 

 

I have looked into this exact thing and done some design work towards it. Was gonna add a bluetooth transmitter in the digital scale for the data logging to transmit to the PC as well as an angular position sensor for the handle. Unfortunately it is just lower on my current priorities list to get this done. The easy way would be to use multiple sizes of set blocks an check rating through the range. I plan to do this soon on a couple of the grippers I have to chart the spring rate so I can try to match it with another project. 

 

btw, Joe I sent you something via PM on my RGC.

 

- Aaron


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#16 OFFLINE   Electron

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Posted 15 July 2013 - 10:19 AM


Chris, this method will easily make that graph you speak of.
All that needs to be done is to pull the handles down slowly and the force throughout is always displayed on the reading.

 
Well, it's a bit more involved than that.  One has to output the force as a signal to a data acquisition card, and then come up with a way to syncronously record close angle.  It can be done It's just the time & expense.  There's other ways one could estimate close angle as well, and sync that up with the force measurements.  

I've thought that through too, but didn't have time to include that. Still don't, so I'll respond with a diagram when I can.
It's not that difficult, I think.

#17 OFFLINE   Autolupus

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Posted 15 July 2013 - 02:06 PM

 

 

Chris, this method will easily make that graph you speak of.
All that needs to be done is to pull the handles down slowly and the force throughout is always displayed on the reading.

 
Well, it's a bit more involved than that.  One has to output the force as a signal to a data acquisition card, and then come up with a way to syncronously record close angle.  It can be done It's just the time & expense.  There's other ways one could estimate close angle as well, and sync that up with the force measurements.  

I've thought that through too, but didn't have time to include that. Still don't, so I'll respond with a diagram when I can.
It's not that difficult, I think.

 

You could record percentage points between fully open and closed the more the smoother and more accurate the graph. An automated system would be nice but you could just measure the deflection then divide it up and measure force at the corresponding points.

It's a system I use when rating springs that couldn't maintain full compression without distortion, being that they are already over-stressed, these are still useful as their working range is usually sub 50 percentile, if that.


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#18 OFFLINE   Big T

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Posted 15 July 2013 - 05:59 PM

Wow are sport is growing I tell ya, I need to get my grippers  rated one day myself  :grin:   Great to hear of how to do this, and the means to be accurate for max force to close grippers.  At the end of the day, "Let's Close Those Grippers"  :rock



#19 OFFLINE   Cannon

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Posted 15 July 2013 - 06:30 PM

Good idea Joe.  I've also dreamed up many other ways to streamline the process, or take weights out of the equation, etc.  Thank you for experimenting with this.

 

I'm saving my money for a computerized rig like this.  :D You could map anything you wanted:

 

 

 

(If you know how to make this happen, please contact me. :flowers:   )  


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#20 OFFLINE   Hubgeezer

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Posted 16 July 2013 - 04:51 AM

When Dave and Greg cme up with the RGC it wasn't really meant to be used quite the way we have morphed it into over the years.  It was called Redneck for a reason.

I often wonder if the two of them are amused as to where it went after their initial fun little gadget got a life of its own.