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AK47
09-01-2010, 07:18 AM
I am trying to understand if i string a racquet at 58lbs on a drop weight machine vs digital one at 58lbs using same string can both racquets feel different. I just got a racquet strung with a drop weight machine, and strings feel lot looser than the racquets done with digital at the same tension.

esgee48
09-01-2010, 07:29 AM
They're both constant pull machines. However, I find that drop weights do tend to pull lighter tension than electric constant pull. The difference IMO is between 2-3 lbs. I believe you can compensate for the drop weight by waiting at least 15 seconds to see assure that the bar does not drop from the horizontal. The electric is always adjusting the tension, so you clamp when it stops making noise.

rich s
09-01-2010, 07:58 AM
I am trying to understand if i string a racquet at 58lbs on a drop weight machine vs digital one at 58lbs using same string can both racquets feel different. I just got a racquet strung with a drop weight machine, and strings feel lot looser than the racquets done with digital at the same tension.

some obvious contributors.....
If the drop weight used flying clamps that would be one factor for the less stiff stringbed.

If the electronic machine had a pre-stretch function and/or tighter fits between the clamps and the bases (because it is a higher end machine) those would be other factors.

Generally.......
whichever machine has a higher build quality you would expect a tighter stringbed and more consistant stringing

BobFL
09-01-2010, 08:18 AM
I am trying to understand if i string a racquet at 58lbs on a drop weight machine vs digital one at 58lbs using same string can both racquets feel different. I just got a racquet strung with a drop weight machine, and strings feel lot looser than the racquets done with digital at the same tension.

You are right. According to extensive experiments the difference is cca. 4lbs.

I found that, for example, 59lbs on dm = 63lbs on dw

WildVolley
09-01-2010, 10:14 AM
You are right. According to extensive experiments the difference is cca. 4lbs.

I found that, for example, 59lbs on dm = 63lbs on dw

Interesting. What were the setups in terms of clamps?

I'd trust a drop weight to be more accurate than an electric if both setups were using the same clamps.

Rabbit
09-01-2010, 10:53 AM
Personally, I think an electric is more accurate since you can visually see the amount of tension being pulled to the tenth of a pound. Likewise, it is more consistent than a dropweight with an equal build since it is pulling to a tension and not relying on an arm.

Irvin
09-01-2010, 11:06 AM
I borrowed a friend's drop weight machine about a month ago because I wanted to see what it was like to use a drop weight. To begine with I wanted to check the tension so I set the tension at 60 lbs and got the bar perfectly horizontal. To my surprise the meter read 53 pounds. I had to set the tension on the bar to 68 lbs to get 60 lbs of tension.

When I pull tension on my Wise tension head 60 lbs reads 60 lbs. But who is to say the Wise and my gauge are accurate?

The moral of the story - find a tension you like and stick with it. If you are just stringing for yourself on a drop weight it does not matter what it reads or what it pulls as long as you like it. If you are stringing for others calibrate it before you do anything.

Irvin

AR15
09-01-2010, 11:39 AM
The scales on drop weights are nothing but a decal placed on the drop weight arm. So, the only fair comparison would be a calibrated drop weight against a calibrated digital.

In my personal experience, and for whatever reason, if my pro strings my racquet with her Neos crank machine set at 60 lbs, and I string it on my Alpha Pioneer set at 60 lbs, the strings will be tighter with my drop weight. My drop weight is not calibrated, and I bet it's been years since my pro's machine has been serviced. So, who's machine is correct? It's impossible to say without proper testing.

Kevo
09-01-2010, 03:04 PM
When I've tested dropweights they have been spot on. Of course I've only tested the 3 I've personally owned over the years, so the sample size is pretty small. They were a KlipperMate, Eagnas Challenger I, and my Stringway ML100. I really couldn't tell much difference between the results, but I didn't try frames back to back off the machines either. The newly strung frames were always played along side previously strung frames.

Anyway, you should try to get your frames strung on the same machine by the same stringer preferably. That assures some level of consistency at least and allows you to find a reliable reference tension.

rich s
09-01-2010, 03:36 PM
The scales on drop weights are nothing but a decal placed on the drop weight arm.

Not always, on my Gamma 602FC the scale was engraved into the drop arm.

Additionally, if those that use a decal have the decal mislocated by as much as a 1/10 of an inch (assuming a 6# weight and a 2" drum - typical on my Gamma) that would only affect the applied tension by .6#


so the only fair comparison would be a calibrated drop weight against a calibrated digital.
only if they had identical turnables and clamp set ups. you couldn't compare a machine with fixed clamps to a machine with floating clamps and expect an apples to apples result.

In my personal experience, and for whatever reason, if my pro strings my racquet with her Neos crank machine set at 60 lbs, and I string it on my Alpha Pioneer set at 60 lbs, the strings will be tighter with my drop weight. My drop weight is not calibrated, and I bet it's been years since my pro's machine has been serviced. So, who's machine is correct? It's impossible to say without proper testing.

Your machine is tighter because it is constant pull and hers is lock out. It is pretty widely recognized that you have to up the tension by about 10% on a lock-out to achieve similar string bed stiffness as achieved by a constant pull machine.......

my $.02

Gamma Tech
09-02-2010, 05:32 AM
Generally.......
whichever machine has a higher build quality you would expect a tighter stringbed and more consistent stringing
rich,
i hate to do this but i have to disagree w/ you on the part i underlined BUT i do 100% agree on the consistency part. the only reason i really know this is a few years ago i went back and forth w/ an international customer that had a 8500 & EsII+. His complaint was that the EsII+ had a tighter string bed and so the 8500 was inferior ($1000vs $3500). Actually what happens is the 8500 is more consistent and you end up w/ a tension closer what you set. using round numbers for the example, our 8500 would re-pull tension in less than .5lbs & have very little over shoot. so if you set it for 60lbs, the string would relax to 59.5lbs & then re-pull, the maximum it might pull is 60.5lbs. so the maximum you'd see on a string/bed would be 60.5lbs or the 60lbs would be maintained on the string/bed. on the EsII+ the tension drop was bigger for re-pull, 2 to 4 lbs. also the way the EsII+ is calibrated is more critical because of the bigger difference. so if it was set for 60lbs the tension could drop to 57lbs but then when it re-pulled it could go to 63+lbs. so you could actually have a tighter string bed but you were actually setting/aiming for a little lower one. so if you set both machines for 60lbs the 8500 would be a lot closer to the 60lbs you were expecting. The EsII+ could be tighter but that doesn't necessarily mean it is better.

a good electronic machine should be a little better/ more consistent because you are eliminating any chance of doing double pulls, ie if you drop the arm & it doesn't go below horizontal and you have to re-pull or the difference in time to raise the bar back to horizontal.

bret

Gamma Tech
09-02-2010, 05:34 AM
I borrowed a friend's drop weight machine about a month ago because I wanted to see what it was like to use a drop weight. To begin with I wanted to check the tension so I set the tension at 60 lbs and got the bar perfectly horizontal. To my surprise the meter read 53 pounds. I had to set the tension on the bar to 68 lbs to get 60 lbs of tension.
Irvin

could you have possibly been lining up the wrong side of the weight w/ the scale?
bret

Irvin
09-02-2010, 07:24 AM
^^ No the weight was on correctly. This was on an Alpha machine and the weight was about 3" wide. Had I lined up the 60 lbs on the top of the weight it would have been off more. To get the stringer to pull 60 lbs of tenson I had the lower side set to 68 lbs. I don't know how much more the higher side of the weight would have read but it would be much higher probably off scale.

Irvin

rich s
09-02-2010, 08:34 AM
rich,
i hate to do this but i have to disagree w/ you on the part i underlined BUT i do 100% agree on the consistency part. the only reason i really know this is a few years ago i went back and forth w/ an international customer that had a 8500 & EsII+. His complaint was that the EsII+ had a tighter string bed and so the 8500 was inferior ($1000vs $3500). Actually what happens is the 8500 is more consistent and you end up w/ a tension closer what you set. using round numbers for the example, our 8500 would re-pull tension in less than .5lbs & have very little over shoot. so if you set it for 60lbs, the string would relax to 59.5lbs & then re-pull, the maximum it might pull is 60.5lbs. so the maximum you'd see on a string/bed would be 60.5lbs or the 60lbs would be maintained on the string/bed. on the EsII+ the tension drop was bigger for re-pull, 2 to 4 lbs. also the way the EsII+ is calibrated is more critical because of the bigger difference. so if it was set for 60lbs the tension could drop to 57lbs but then when it re-pulled it could go to 63+lbs. so you could actually have a tighter string bed but you were actually setting/aiming for a little lower one. so if you set both machines for 60lbs the 8500 would be a lot closer to the 60lbs you were expecting. The EsII+ could be tighter but that doesn't necessarily mean it is better.

a good electronic machine should be a little better/ more consistent because you are eliminating any chance of doing double pulls, ie if you drop the arm & it doesn't go below horizontal and you have to re-pull or the difference in time to raise the bar back to horizontal.

bret

never thought of it from that perspective.....

I was looking at it from racquet mounting/shifting, clearance between clamp shafts and bases, tightness of clamp bases to the turn table, how close you can get the clamps to the frame, etc.....

good insight.....

Kevo
09-02-2010, 04:41 PM
^^ No the weight was on correctly. This was on an Alpha machine and the weight was about 3" wide. Had I lined up the 60 lbs on the top of the weight it would have been off more. To get the stringer to pull 60 lbs of tenson I had the lower side set to 68 lbs. I don't know how much more the higher side of the weight would have read but it would be much higher probably off scale.

Irvin

Was this one of the machines that has a two part weight? If the little badminton sliver was missing, that might explain the discrepancy. Or it could have been the sticker issue as mentioned earlier.

Irvin
09-03-2010, 03:05 AM
Was this one of the machines that has a two part weight? If the little badminton sliver was missing, that might explain the discrepancy. Or it could have been the sticker issue as mentioned earlier.

It was an old Alpha Progression (I think) if there was a weight missing I am not sure. I will try to call my friend later and see.

Irvin

aussie
09-04-2010, 09:18 PM
Some time ago I ran an extensive range of tests on my Klippermate using an accurate digital luggage scale. I was very surprised at the accuracy the K'mate pulled - particularly between about 52 to 67. As to possible tension loss due to floating clamps, tie offs etc, well, that's a different story.

My ERT300 definitely shows me that when relating the dynamic tension to the stringbed tension on a freshly strung stick, the resulting tension is considerably lower than the accurately pulled tension. However, even on professionally strung sticks, I'm yet to see the ERT 300 show a tension anywhere near what the pro was supposed to have strung it at.

So long as string jobs are consistently reproduced you really get to know what feels good to you. Whether a string tension of 62 is really 55 at the end of the day doesn't matter - if it feels right to you and you can get the exact same "62" string job time after time, that is what really matters. It's the consistently replicable string job that we all look for.

LanEvo
09-04-2010, 10:27 PM
SO how do you calibrate a dropweight? Also, do you guys just buy a tension scale to measure a dropweights tension? Or how do you do it?

Irvin
09-05-2010, 02:52 AM
^^ you don't calibrate a drop weight. It is right or it is not. You could take the sticker off that has the weight numbers and replace. If you know how much it is off you can do it in your head and just correct the weight.

I was also surprised when I borrowed my friends drop weight machine. There were three marks on the gripper stand. One just above horizontal, one for horizontal, and another below. Any where inside those three marks was just about dead on. That gave me about a +- 5 degree range where the tension was correct.

Irvin

aussie
09-05-2010, 04:14 AM
^^ you don't calibrate a drop weight. It is right or it is not. You could take the sticker off that has the weight numbers and replace. If you know how much it is off you can do it in your head and just correct the weight.

I was also surprised when I borrowed my friends drop weight machine. There were three marks on the gripper stand. One just above horizontal, one for horizontal, and another below. Any where inside those three marks was just about dead on. That gave me about a +- 5 degree range where the tension was correct.

Irvin

Yes, on the Klippermate it is 1.5 inches above or below horizontal where the tension remains very accurate. That is a 3 inch range of tolerance which is 100% achievable. In fact, my tests show that you can even go a little outside of the 1.5 inch above or below and still achieve very good accuracy.