settings on electronic machines

[ericb]

I recently upgraded my stringer to the Silent Partner DG which is a constant pull electronic machine. It has two settings that I don't play with much, but was wondering how people here treat these things (David I know you won't resist since you have the Aria and a DG sitting somewhere at home ...)

1) pre-stretch: this setting is presented as a percentage of the tension, e.g. for a 60lb reference tension, and a 10% pre-stretch, the machine pulls 66lbs, and then backs off to a constant pull of 60. I have 3 possible settings: 0, 10 and 20%. Which settings should I use for which kinds of string?

2) pull speed: 3 settings here - low, medium and high. So far I tend to use medium as I've had a few syn guts break at high speed when pulling the early mains. Again, recommendations for different string types?

Cheers,

Eric

[David Pavlich]

Bonjour, Eric (I stuck that in there since you're from Montreal and no, I don't speak French).

I sold my DG and replaced it in the living room with my Aria. I have a Sensor in the shop.

I don't use the prestretch much except when I string new frames or frames that I just installed new grommets. This allows the grommets to seat in a little better. Some people string a pound or two higher to seat the grommets.

I prestretch the whole string instead of prestretching on the machine. One, it stretches evenly across the length of the string and two, it relaxes the coil memory to make stringing easier.

When machine prestretch is used, the stretch is different for each pull because of the different string lengths. Does this have an effect on the stringbed? I'm sure it's subtle, but that's my reasoning.

If you want to use the prestretch, strings like Prince More Feel that are extremely elastic, use the maximum. On the other side, I'd use the minimum for polys. Stuff like Sensation or Xcell, middle setting would do.

Speed settings: Kevlar-the slower the better, poly in the middle and the rest at high speed.

You may have done this already, but if you haven't you might consider upgrading the upper clamps to the Aria clamps. The Aria clamps are 3 tooth and diamond dust coated...much better than the standard DG clamp and they fit into the DG base. If you don't, make sure you clean your clamps frequently.

David

[ericb]

Thanks for the advice David. Upgrading to the Aria clamps is definitely a plan in the future. I had a look at them at the Silent Partner factory in Toronto when I picked up the DG, and they definitely look better, but for now the standard clamps on the DG are reasonable. I am cleaning them often. I hadn't thought of your trick of roughing them up a bit - I might just try that.

As for the pre-stretch, so far I haven't used it on any jobs since I like to try things on my own racquets first before doing something on someone else's. I'm a little fearful of even using the minimal 10% on my racquets since I normally string at 60lbs, but when I string hybrid I use J.C.'s method which means I'm dropping my mains to 56, and stringing the crosses at 60. Problem is, the two outer mains get 64, and with a 10% pre-stretch that means the initial pull would be 70.4lbs which I fear is too much for the outside of the frame and some strings. I also agree with your reasoning about string length afterting the overall stretch amount.

As for the pull speed, again I agree with you in principle, but in practice I can't seem to pull some syn gut at high speed for the longer mains since it occasionally breaks around the grommet loops. Maybe I'm doing something wrong.

For example, on a PD, I put a starting clamp at the head on the outside of the frame (1H), tension and clamp the other 1H. Then I pull the string with the starting clamp attached, clamp, and then remove the starting clamp. It's the next pull (2T) which often breaks the string around the grommet loop between 1H and 2H if I use high speed. It's never happened at medium speed. This has happened with superfine play 16 and 17. Any insight?

Cheers,

Eric

[David Pavlich]

Hmmmm...that's the way I start my stringing and I have no problem. The first thing I'd look at is your starting clamp and what it's doing to the string. What I'd do is start off a string job by tensioning the first main and let the machine hold if for a couple of seconds. Now release the tension and let the string relax. Take the starting clamp off and look at the string very closely.

It seems to me that one of two things is happening. Either you have a bad spot on the starting clamp that's creating a weak spot or the string is slipping a bit which would also create a weak point. What brand of starting clamp are you using?

Also check the grommet/bumper for bad spots. You might want to tube that main and see if that helps.

As far as your concern about the overtensioning hurting the frame, I wouldn't be concerned. It's a momentary burst. Now, if you were stringing at 72 lbs reference tension, then I'd be just a little concerned.

I've done it a lot for the reasons I explained earlier and never had a problem. A lot of pro players request machine prestretch, by the way.

[ericb]

What I'd do is start off a string job by tensioning the first main and let the machine hold if for a couple of seconds. Now release the tension and let the string relax. Take the starting clamp off and look at the string very closely.

I did this today - no noticeable damage to the string where the starting clamp was at all.



What brand of starting clamp are you using?

The blue Babolat one, and it's less than a year old. I've yet to see string slip in it.



Also check the grommet/bumper for bad spots. You might want to tube that main and see if that helps.

This has actually happened to me on several different frames, one of which was a brand new stick. It has never happened when pulling at medium speed.

Cheers,

Eric

[David Pavlich]

I'm still perplexed. Your machine pulls nowhere near as fast as my Sensor, yet I have no problem. You've got a good clamp; it's the same one I use. As a matter of fact, I've used a Rab and a Wilson starting clamp the same way with no problem. Strange. I must say, I can't think of anything else without actually seeing the process. Sorry.

David

[ericb]

Yeah, me too. I spoke to Silent Partner about it, and he said it was normal for some syn gut strings to break when pulling at high speed due to their lower tensile strength. I still find it a little strange though.

Do you place your starting clamp so that it is lying down, or facing up as in my pictures in the other thread? When I tension the string the starting clamp is holding in order to clamp it normally and remove the starting clamp, the starting clamp rotates 90 degrees since it is no longer touching the racquet. I'm always careful to return it in the same direction before releasing the string. Could this quarter twist be a factor?

Cheers,

Eric

[David Pavlich]

It's h*ll getting old. I just put my latest response to this thread on the clamp thread! Sheesh.

As far as the clamp's position, I let it lay down resting on the machine. I doubt that this would make a difference.

Check out the rest of my reply on the other thread. Lordie...

David

[David Pavlich]

Update:

Since I had my Yonex "anomoly", I've done 2 more Yonex demos, a HH 5.3 OS, a Liquid Metal Fire, 2 Babolat Pure Control MPs, a Babolat Drive Z Lite, a HH 5.2 mp, 2 Prince Thunderstrike Longbodies and a Prince More Power 1150. No popped string.

It appears my episode was indeed a rough spot on the grommet/bumper face.

David

[ericb]

I've been lucky lately - it hasn't happened :) I'll try resting the starting clamp on it's side next time and see if it improves my odds. I was just putting it perpendicular to the frame so that I had more room for stringing through the adjacent grommet. I would also think that the chances are higher of the string getting bent on racquets like the PD where the grommet strip is inlaid in the bumper. This reminds me ... there's another thread I should start about flared grommets ...

Anyway, I'll keep you posted.

Cheers,

Eric

[David Pavlich]

Eric,

I added to Jay Cee's comments about the PD grommet strips.

One more question: I'm going to assume that the answer is yes, but do you make sure you aren't scraping the string when you remove the starting clamp? It wouldn't take much to create a weak spot.

David

[ericb]

David,

I don't think I'm creating a weak spot. I never remove a clamp that is still holding tension, i.e., I always tension the string between the machine and the starting clamp, clamp with the regular clamp, and then remove the starting clamp. I don't really see how else I could do it. Please enlighten me if there's a better way.

Cheers,

Eric

[David Pavlich]

No, it sounds like you're doing it the same way that I do it. I'm glad to hear that you've been having better luck lately.

What brand and what type of string are you using? Which string is it that seems to pop most often? I'm gonna' figure this thing out yet!

David

[ericb]

I'm pretty sure it's always been Babolat superfine play - both in 17 and 16 gauges.

-eb

[David Pavlich]

I'm pretty sure it's always been Babolat superfine play - both in 17 and 16 gauges.

-eb

Well, that doesn't help because I used to string this stuff. You're a trouble maker, Eric! :D

David