Lockout vs Electronic "Constant Pull"

[TechnoJock]

I have been stringing for 15+ years using an old (1997) Gamma ELS 6500 machine. I was able to string my frames at 57 pounds on my Wilson K-Factor 6.1 16x18 then switching to the same tension/string on my Babolat Pure Drive Tour. I sold my machine - but after about 6 or 7 non-consistent string jobs - I purchased a Gamma 5003 sc with 2-point mounting. After adjusting the new machine using the tension gauge - it appears that 57 pounds for this string is way different. In fact - I seem to have to be down around 48 pounds to get similar tension. I was always under the impression (not that I do impressions - actually I do so forget that thought) that the lockout machine would be looser at the same tension due to the fact that the string will stretch. The stretching is inherent with the constant pull as if the string stretches the tensioner will pick up the slack. On my old machine one could hear it jockeying to keep the tension constant. Am I missing something here or is this expected behavior?

 

[jim e]

Was your old machine ever calibrated when you had it? Also did you calibrated your present machine as well. If not one could have been off and caused issues you realize.If you never checked your old machine, you may never know exactly where the issue may be.
Constant pull does give a a stiffer string bed, and the % depends on racquet size and type of string.

 

[TechnoJock]

That makes perfect sense - just assumed the electonic machine calibrated when I received it would never need to be re-calibrated... Thanks.

 

[Irvin]

How did you calibrate your 5003? Some people think that they should pull tension and let the tension settle then adjust the tension but that is not the case. The tension you adjust to should be the tension immediately when the lockout kicks in. If you allow the tension to fall, and it will, you're not adjusting the lockout right. Also use a spring tensioner and not a digital scale.

 

[Irvin]

I suspect that one or both of your machines was not adjusted properly.

 

[Karma Tennis]

Also use a spring tensioner and not a digital scale.

@Irvin, why not a digital scale?

 

[Irvin]

@Irvin, why not a digital scale?

When you use a digital luggage scale the tension tends to oscillate a little. If you use a spring scale the the spring in the scale tends to cushion the string. I was told by the old @Gamma Tech (Bret) and @abllee2198 to use a spring scale not a luggage scale. I think both will get you close as long as it does not oscillate much. No matter what scale you use you want to set the tension for lockout at lockout not a resting state.

 

[Irvin]

Just FYI make sure you check pull tension or lockout tension not the settle tension.

 

[Karma Tennis]

When you use a digital luggage scale the tension tends to oscillate a little. If you use a spring scale the the spring in the scale tends to cushion the string. I was told by the old @Gamma Tech (Bret) and @abllee2198 to use a spring scale not a luggage scale. I think both will get you close as long as it does not oscillate much. No matter what scale you use you want to set the tension for lockout at lockout not a resting state.

It may depend on the type of Digital Scale being used. I purchased one on the big Auction Site for about $2 that some Tennis Stores in the local area were trying to sell for $80. lol.

I think the key to using a Digital Scale for calibration is to use the Stiffest Strings you can find to do the "check pulls" with.

I set the system up. Wind the crank to tension the string. And then check the reading on the Digital Scale as soon as lockout occurs. Never had a problem doing that.

At lockout, the reading on the Scale is close enough to the tension setting on the tension head. If I then leave it, I can see the Digital Scale reading slowly start to reduce and eventually settle on a lower number. (A "FUN" activity for me is doing this check with strings that have different stiffness ratings and elasticity.)

My machine is over 25 years old. I've had it for a few years now. Checked the calibration when I got it. Check it every 30 or so string jobs. Haven't needed to adjust the tension head to this point. (I only do about two racquets per week though.)

(@Irvin, you may recall that I purchased a new tension spring about a year ago. I intended to replace the old one as I thought it would have deteriorated over the years. But the feedback I got from you and some of the other esteemed gurus here suggested to just leave well enough alone. Which I have. So the new spring is still in the drawer. And the old one is still providing sterling service.)

 

[Irvin]

I think the key to using a Digital Scale for calibration is to use the Stiffest Strings you can find to do the "check pulls" with.

I set the system up. Wind the crank to tension the string. And then check the reading on the Digital Scale as soon as lockout occurs. Never had a problem doing that.

I used to believe the same thing and even suggested using Kevlar. For some reason Bret (old Gamma Tech) said to use the string the scales came with cheap 15 gauge nylon.

But if you’re measuring the tension at lockout it should not matter if the string stretches or not.

you may recall that I purchased a new tension spring about a year ago. I intended to replace the old one as I thought it would have deteriorated over the years.

Don’t ever replace that spring you could mess up the tension linearity. You should actually measure the tension at different tensions when you check it. Say 30-40-50-60 lbs. if the machine is linear or off very little your great if not even though one tension is spot on if you don’t always use that tension there’s a problem. Bret had a worksheet for adjusting the lineraity but I never asked him for it. It is not an easy procedure as I understand it.

 

[Karma Tennis]

I used to believe the same thing and even suggested using Kevlar. For some reason Bret (old Gamma Tech) said to use the string the scales came with cheap 15 gauge nylon.

I had a reel of Wilson 1.4mm SG (Nylon) which was quite stiff. And that did work pretty well for calibrating too.

Don’t ever replace that spring you could mess up the tension linearity. You should actually measure the tension at different tensions when you check it. Say 30-40-50-60 lbs.

Yes, Thanks to you guys, I have no intention of doing so. And am grateful for the advice because there is a little bit of work involved in doing so.

Yes, when I calibrate, I check it at those settings as per your original advice.