Crank Machine Calibration

celito

Professional
Bought a refurbed Gamma Progression ST II from Gamma and started stringing (for myself). First couple of racquets strings felt pretty tight. So I started going down the rabbit hole. Downloaded RacquetTune app and it showed (after a few days and one hit) that a racquet strung at 48 lbs was showing at 55 lbs. I now the app isn't exactly precise, but a third racquet w/ different string also showed it being high. After much research, decided on a fishing digital scale (cheap $11). With my tensioner at 50 lbs, the scale showed 60-62 lbs. So just to be sure, tried a $45 fishing scale (mentioned here in another thread) and it also showed it being off by 10-12 lbs. Because I am too damn curious, got a Gamma calibrator (the green one) and to my surprise, it's reading 16 lbs higher than my machine setting !!!

Yes, I know that for personal stringing, the exact tension isn't that important ... just string whatever feels good. And yes I know that crank machines lose tension right away as your stringing vs constant pull or drop weight. But, I am a bit OCD and curious about this ... and have my machine more or less calibrated. Plus, I may string for some friends an people in my neighborhood. So want to at least in the ballpark. So what's the best way to have this more or less calibrated ? Any chance this Gamma calibrator is also a bit off and the digital scales are on point ?
 

esgee48

G.O.A.T.
Go to Gamma Sports dot com; select stringing machines and the model which is ST. Click on the manual and go to page 14 to see how to calibrate the tension head. You could probably download the PDF.
 

alfd

New User
I bought a new Gamma X-ST some years ago. It was +5 lbs off. Used a Gamma calibrator after checking it with a fishing scale (they gave the same result). I have strung 400 rackets since that, and the machine is still spot on! I find it strange that Gamma hadn´t calibrated it from the factory though!
 
Last edited:

celito

Professional
Go to Gamma Sports dot com; select stringing machines and the model which is ST. Click on the manual and go to page 14 to see how to calibrate the tension head. You could probably download the PDF.

I have the instructions on how to adjust it ... just wondering what reference tension reading should I use.
 

Irvin

Talk Tennis Guru
I have the instructions on how to adjust it ... just wondering what reference tension reading should I use.
Doesn’t the procedure in the OM tell you? I believe my old Gamma was checked at three different point like maybe 40-50-60. You not only want the tension accurate you want it linear.
 

celito

Professional
Doesn’t the procedure in the OM tell you? I believe my old Gamma was checked at three different point like maybe 40-50-60. You not only want the tension accurate you want it linear.

Manual just says calibrated it at 60 lbs. I am more interested in the tool used to calibrate it. The instructions on how to calibrate it is not a problem. Was a bit surprised to see a significant difference between the gamma and the fishing scale. Just looking for some tips if there are any.
 

Irvin

Talk Tennis Guru
Manual just says calibrated it at 60 lbs. I am more interested in the tool used to calibrate it. The instructions on how to calibrate it is not a problem. Was a bit surprised to see a significant difference between the gamma and the fishing scale. Just looking for some tips if there are any.
The tool is nothing more than an allen wrench or hex key. At least it was on mine.
 

esgee48

G.O.A.T.
I have the instructions on how to adjust it ... just wondering what reference tension reading should I use.
Google the weight of a gal of water. Measure out 5 or 6 gal. See whether the Gamma or digital scale is correct. (8.3 lbs per gal)
 
Top