Gamma X-6FC Calibration seem to be off

[jackedo]

Does anyone know why that would be? I got this X-6Fc stringer from the auction site. The unit looks new. I strung my racket with TOA syn gut hybrid at 45# M and 50# X and it plays like it 60# +. I used my old spring fish scale gage to check tension. Not the most accurate device, but all I had to use. The scale showed the pull tension is 6# more than what is marked on the tension bar. The Drop Weight looks like the one pictured in the Owner’s Manual and weights about 6#. The drop weight doesn’t have any markings to id it as a Gamma unit? Could this weight possibly be from another machine?

Jack

 

[gjoc]

You need to check it more accurately than that before you can conclude it's off.

Do you have something of a known weight, like a dumbell or a barbell plate, maybe 20, 30, or 40 pounds?

Tie a tennis string to that and hang it off the machine from the tensioner such that it's applying a known tension, then set the drop weight to match that tension and see if it's approximately balanced (with the drop weight at horizontal, obviously).

You can also double-check your assembly to verify everything's together right. The knob on the weight is down, towards the rotator, and the rod is all the way into the rotator, etc.

When you compare this string job to previous ones and say it feels much harder, how were the others done? Was it with a lockout (spring/crank) machine? This one is constant pull and is going to typically string the racquet 5 to 10 percent tighter than a lockout machine, so you'll need to adjust tension downwardly to get the same results/feel as with a lockout tensioner.

 

[dancraig]

__________

 

[jackedo]

I probably should have said --I checked the old fish scale at 30# using a couple of bar bell weights and it was right on the money. I used this old scale to calibrate my other stringer. I’ve been using it from the early 70’s. It’s a Serrano two point portable with flying clamps that I use to take with us to restring my kids rackets at tournaments way back then. It used a thing called a tensioniser to pull the string. Not really good with the newer rackets, worked great on wood. The tensionizer worked of a bunch of friction disc. I think it would be considered a constant pull device.

Jack

 

[dancraig]

The poundage numbers could be in the wrong place on the bar. If they are printed on a strip, (I haven't seen that machine in person) you could remove the strip and place it in the correct position. I suppose you should really be sure this is the problem before removing and replacing the strip.

 

[jackedo]

Gamma somehow etched these numbers into the metal rod for both pounds and kilograms. The first marking is 20# the lowest reading so the metal rod seems to be at the proper depth. I suspect the weight may not be correct, but the owner’s manual doesn’t give a value for the front, back, or the combined weight?

Jack

 

[dancraig]

Was the machine sold as new?

 

[dancraig]

Gamma somehow etched these numbers into the metal rod for both pounds and kilograms. The first marking is 20# the lowest reading so the metal rod seems to be at the proper depth. I suspect the weight may not be correct, but the owner’s manual doesn’t give a value for the front, back, or the combined weight?

Jack

For what it's worth, this product description says it pulls from 8 pounds.
http://www.atssports.com/tennis.cfm?prodid=270

 

[jackedo]

Yes -- You're correct -- It has a third scale on the other side of rod calibrated for the small drop weight when they are seperated.

Thanks Jack

 

[dancraig]

There is a Gamma person here called "Gamma Tech". Maybe tomorrow he will read this and have some ideas.

 

[gjoc]

The 20# indicator should be flush with the point where the rod enters the base, when the rod is all the way in. I think you're saying that yours is like that. (There's no sticker/decal Dan, the numbers are stamped right into the steel rod).

The weight will fit onto the rod either way when you assemble it (right side up or upside down). The knob should be at the bottom end of the weight, closer to the rotator. Is it?

Note that the picture at the bottom of page 3 in the manual showing the weight about to be put on the rod is deceptive, because it looks like they're putting it on upside down, but the text is clear as to which way it goes.

It should look like it does in this photo (knob at the bottom of the weight):

There's no part number or other markings on the weight on mine.

I don't know the weight of the weight (I don't have an accurate scale to measure it), but it's 2.695" in diameter and 3.050" in length.

I did check the tension on mine at one point to confirm I had mine all together right, using the Gamma calibrator, and mine was absolutely dead-nuts on.

I still think your scale sounds fishy (lol). The spring in something as old as that must be weaker than it once was, making it read too high.

I suppose it's possible that the guy you bought it from gave you the wrong part/weight, but at least now you can check its dimensions to see.

Not sure what else to suggest or offer. There's not a lot to it, just geometry and gravity--nothing to adjust or calibrate beyond getting it assembled correctly.

Like Dan said, maybe Gamma Tech will have something to offer or suggest.

 

[Gamma Tech]

the only things I can think of are:
1. how were your rqts. strung before you got you X-6FC?
2. are you pushing the bar down? is the bar parallel to the ground?
3. in the picture above do you have the weight-end with the knob, aligned with the desired tension. ie if you want 60lbs do you have the end of the weight at 60lbs and 61-64ish is covered up.
4. it sounds like the tensionizer would be considered a 'lock out machine' because the frictions disc are holding the tension and not pulling more, like the disc brake holding on a spring tensioner.

bret

 

[jackedo]

Thanks guys for all the help. My device is exactly as described by gjoc. The picture at bottom of page 3 of the Owner’s Manual is wrong and did cause me a problem until I read the description on page 7. I now have confidence that my device is all Gamma. I guess I’ll have to find a digital scale that will measure up to 80# to tell how much the pull is off (if any). I can compensate if I know the amount and that it’s linear. If its off--the why --will remain a mystery. Maybe gravity is different here in Oregon.lol

Thanks again for the help

Jack