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Gripper Calibration Device


Evan Raftopoulos

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Are these available for sale or people make their own? Any alternatives or set up ideas? I'm trying to figure out a way to secure the gripper while hanging weights from it using a strap. I came up with a set up but it was pretty sketchy and I'm trying to find something better. My priority is to know the relative difficulty level of my grippers, not necessarily to compare what I find with other ratings like CPW's. I have an ER HiRes Hydraulic Hand Dynamometer (200 pound capacity) that I can hang the weights from right after the gripper closes for an accurate reading.


this is my dynamometer

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thanks man, I know about the device but is it for sale anywhere? I'm trying to read through that thread.

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This was just brought up a month ago. All you had to do was search RGC device. This thread in particular is great.

http://www.gripboard.com/index.php?showtopic=43859&hl=%2Brgc+%2Bdevice

Have to agree, this thread by Jared is really useful and shows how you can create your own RGC if you have the welding experience

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No one sells them. Maybe you could throw some cash at Jared.

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Also cannon posted his idea for a no weld RGC rater.

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Also cannon posted his idea for a no weld RGC rater.

I think that was a different thread though..?

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I always wondered why a 'device' is needed; would it be possible to clamp the bottom handle in a vice (vise for most here!), with some protection for the knurling, and use the strap / spacer idea to stop the strap fouling on the rest of the vice?

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cool, thanks guys

I came up with this setup today at my work (see pic)

Also, I realized that we have a Chatillon FCE-200 Functional Capacity Evaluator that has been sitting there, so I thought to try using that instead of weights (using my wt/force). I’m still not very happy with the setup though. I might ask a friend to make the rgc for me.

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I always wondered why a 'device' is needed; would it be possible to clamp the bottom handle in a vice (vise for most here!), with some protection for the knurling, and use the strap / spacer idea to stop the strap fouling on the rest of the vice?

I tried many different things today, even having the gripper between the leg press machine plates (kind of stupid, I know). From what I'm learning you need some sort of setup that is consistent (the forces always applied at the same points),provides good stability for the gripper, and also provides with reliable readings. I think that unless you try what you are suggesting you can't know for sure if it's a good idea.

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Only like 25

Here is what it says:

Use 1/4" G5 bolts for the "uprights" and just drill holes at the front of the arm and bolt them into place. Then a couple hoseclamps to hold the small section of round tube in place. Finally, lag screw that mess down so it hangs over the edge of a bench. Done.

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I tried rating some spring positions of the super vice gripper (See pics)

I used a cable machine and 1 3/8 inch strap. I expect at least a +/- 2 pound error (and more with heavier settings) given that the rating setup is not optimal and that I could have done a better job verifying the wt with the hydraulic dynamometer.

The first number in parenthesis is the spring position on the bar closer to the handles, the second the one further away.

So based on that if you want something around 135 pounds (+/- 2), you set the spring at position 2 on both bars (keep in mind I could be way off).

I also had a Heavy Grip 250 with me which I rated with the help of an extended handle (I guess I could rate any gripper this way ) but here is the thing, I found it to close with 130 and not with 127.5. It could have been 129 but the weird thing is that HG 250 from what I read online is usually just a bit harder than CoC#2 so this didn’t make much sense. But I also rated my pre-rated trainer (56 pounds) using this method and I got the same number as Cannon. I will try again next time with verifying with the dynamometer and using a more stable surface than my hand and perhaps a 1 inch strap instead. Also, the cable machine has only 100 pounds so then I was hanging wts on the side of the plates, but I don't know if that would affect the rating.in addition, the extended handle is couple mm thicker so the distance to close is reduced. So again I don’t want to be misleading, keep in mind that I have not tested this setup extensively for accuracy and reliability so don't accept what I 'm saying here as good data. But I'll keep trying to figure this grippers rating thing out.

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I made another one, the 1st attempt was no good it wasn't long enough, the 20kg plates were catching on the rack.

RGC Mk2:

61CB8A9E-A713-41BD-9815-E8AE6AC532CC.jpg

quite a simple design, took 15 minutes to make, and is rock solid in the rack once the spinlock nut it tightened up. fits a variety of racks too.

Edited by exarmy
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Very nice stuff in this thread.

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With mine the numbers were close to the ratings I got from Jedd and CPW. I think the difference is I take my plates weights at face value not the actual weight. So the stronger the gripper the further off my numbers were.

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You can take your plates to the post office, and weigh them. I usually go off hours, and use the automated postal center scale. I have some 45's that are 3# or more heavier than they should be. Some of the smaller plates I have are actually under. If you get a few different plates weighed at the post office, then you can figure out how far off your bathroom scale is.

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With mine the numbers were close to the ratings I got from Jedd and CPW. I think the difference is I take my plates weights at face value not the actual weight. So the stronger the gripper the further off my numbers were.

Here is how I have been rating.

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That's the way I do it Jared Just gonna have to calibrate my plates or scale. Just might go by the post office tonight.

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That's the way I do it Jared Just gonna have to calibrate my plates or scale. Just might go by the post office tonight.

Most all of my plates are calibrated but still its just faster to throw them all on the scale then to add them all up.

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That was really cool, I've never actually seen how the grippers get calibrated. I can't wait to see the video of the new set up you talked about

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