Calibrated #3

[stevey7]

Just got my #3 calibrated,its come back as 154 pounds just wondering if its average or just above because im having a lot of trouble closing the last few mm.

[Bob Lipinski]

It may not be "average", but it is pretty average. Most I have tried are around there. Also depends who calibrated it.

[Dave2]

It may not be "average", but it is pretty average. Most I have tried are around there. Also depends who calibrated it.

Which are some of the hardest ones you have felt. I had mine calibrated @ 150 on my own rig.

[EricMilfeld]

Also depends who calibrated it.

This is true to the extent that calibration figures have become meaningless when the person calibrating is not taken into account. Apparently the numbers I've been attaining are lower than most, if not all. At first I thought we were all on the same page regarding the particulars of the procedure. It might be a good idea for all the guys doing this to get together and compare notes in an effort to try and better standardize the procedure.

[mightyjoe]

Eric, you should post a video on how you calibrate grippers.

If guys are not doing it the way you are (particularly one step that you explained to me)

then they are getting it wrong for sure.

This is why there are so many inflated readings out there. No doubt.

[cemery]

Eric, you should post a video on how you calibrate grippers.

If guys are not doing it the way you are (particularly one step that you explained to me)

then they are getting it wrong for sure.

This is why there are so many inflated readings out there. No doubt.

Eric should make a vid on his calibrating process.

[Cannon]

Also depends who calibrated it.

This is true to the extent that calibration figures have become meaningless when the person calibrating is not taken into account. Apparently the numbers I've been attaining are lower than most, if not all. At first I thought we were all on the same page regarding the particulars of the procedure. It might be a good idea for all the guys doing this to get together and compare notes in an effort to try and better standardize the procedure.

The cross-calibrating is a good idea too. Eric, you calibrated an Elite at 164 for a mutual friend of ours, Greg Griffin. I have that gripper right now and also got 164. I'd be interested in hearing about your process and the possible "extra step" that Joe mentions.

[Cannon]

Also depends who calibrated it.

This is true to the extent that calibration figures have become meaningless when the person calibrating is not taken into account. Apparently the numbers I've been attaining are lower than most, if not all. At first I thought we were all on the same page regarding the particulars of the procedure. It might be a good idea for all the guys doing this to get together and compare notes in an effort to try and better standardize the procedure.

I would also be willing to either type out my process or make a video. Matti already has a video out there.

[EricMilfeld]

Matt, that's encouraging that you and I got the same results.

Here's what I think are critical points:

1) Insure the gripper is sitting perfectly level.

2) Insure the 1" strap is flush with the face of the handle, and not the bevel.

3) When the weight is hanging from the handle the gripper should be balanced, requiring little if any support from the sides to prevent it from toppling over.

4) Oil the spring thoroughly.

5) The weight it takes to close the gripper is not always the weight it takes to keep it shut! After I get the gripper to close, I then check to see if I can take off some weight without the handles opening.

[Sher]

Validating the methods used by calibrators would really help ensure consistency. Perhaps someone could designate a couple of grippers as Standards and let the calibrators use them to check and tweak their method? For instance, an average of three measurements should be within one sigma (sx on a sci calculator) of the 'standard' weight. That would check both accuracy and precision (as well as reproducibility depending on the amount of time between measurements). Maybe also choose a light and a heavy weight gripper to test the methodology over most of the calibration range (say, a #1 and a #3.5). Validation would also enable you to quantitate differences between the current methods being used. [Extremely 'detail-oriented' calibrators (I know one in particular!) could also check effects of temp and humidity to see if those should be controlled (by perhaps just avoiding extremes) or are statistically insignificant.]

Just a bit of food for thought.

Btw, those who calibrate grippers are such a boon to this community - it's evident that it's a much appreciated service.

[Cannon]

Matt, that's encouraging that you and I got the same results.

Here's what I think are critical points:

1) Insure the gripper is sitting perfectly level.

2) Insure the 1" strap is flush with the face of the handle, and not the bevel.

3) When the weight is hanging from the handle the gripper should be balanced, requiring little if any support from the sides to prevent it from toppling over.

4) Oil the spring thoroughly.

5) The weight it takes to close the gripper is not always the weight it takes to keep it shut! After I get the gripper to close, I then check to see if I can take off some weight without the handles opening.

All great points.

Regarding item 3, I start over if I can't get the gripper balanced perfectly. The handles should be coming together right on top of each other.

Regarding item 4, if the gripper is not seasoned--like has been sitting around and really dry--I feel it should be oiled and closed a few dozen times to get the creaks and pops worked out.

I also force the gripper shut, which I think Bob does as well. For example, if I was calibrating a #3, I would hang about 140# on the gripper to start, push it shut and see if it pops open. If it does, I add weight until it either closes, or no longer opens after being push shut. Then I back off the weight by a small increment and add it back in small increments until, like Eric says, the handles open a little when a weight is removed. I usually check that with my 1# weight as that is usually the difference between the handles opening or not, except for the hardest grippers sometimes.

[Sher]

Validating the methods used by calibrators would really help ensure consistency. Perhaps someone could designate a couple of grippers as Standards and let the calibrators use them to check and tweak their method? For instance, an average of three measurements should be within one sigma (sx on a sci calculator) of the 'standard' weight. That would check both accuracy and precision (as well as reproducibility depending on the amount of time between measurements). Maybe also choose a light and a heavy weight gripper to test the methodology over most of the calibration range (say, a #1 and a #3.5). Validation would also enable you to quantitate differences between the current methods being used. [Extremely 'detail-oriented' calibrators (I know one in particular!) could also check effects of temp and humidity to see if those should be controlled (by perhaps just avoiding extremes) or are statistically insignificant.]

Just a bit of food for thought.

Btw, those who calibrate grippers are such a boon to this community - it's evident that it's a much appreciated service.

[Edit: Whoops - this re-reads as a bit critical, not at all what I intended. Redirect: These are just considerations to add to the brainstorm going on. There's always something more to do to improve a process but it can easily become a matter of decreasing payoffs especially when the current system has been very effective.]