String creep

[MDM44]

Does the stock Matrix string ever settle in and stop creeping ?

[colouredchameleon]

According to the Excalibur's Matrix String Description it professes reduced CREEP as one of its attrbutes. Maybe yours falls outside the expected norm.
Look on the bright side excessive creep could be a blessing in disguise reducing the risk of limb damage even greater than the 60%
With one exception and that is letting your brace height get TOO LOW.

Constructed of BCY Dynaflight 97 material Excalibur’s Matrix Crossbow String produces two distinct advantages. First, it increases speed, which is a key attribute of Matrix Series crossbows. The Matrix 380 Xtra, for example, shoots 380 fps! The second advantage is reduced creep which allows you more time shooting, less time tuning.

[Boo]

Yes it does. When you put your bow away put a few or more twists in the string to preload it a bit more. Store it were it's warm. Shooting is the fastest way to get the creep out.
The wax between the strands and filaments is what is causing the creep, the string material itself does not creep much.
You could build a string stretcher that you might want anyways to reserve the string.

[MDM44]

Thanks, that makes sense. Been lubing rail every 3-5 shots and waxing every 5. Will be probably go the custom string route in the future ,but, was told factory string would be more forgiving of "rookie" mistakes. Might put the wax a little thinner next time .

[Boo]

A stretching/serving rack/jig makes so much sense.
Go to the bottom of this page to check out a simple but super strong design.
http://boocustomstrings.com/importantstuff.html

[Significent]

Boo, I'm in the process of building a slightly modified version of your serving jig. How do you know how much torque to put on the clothesline hook nuts when either reserving or just stretching a new string?

[nchunterkw]

I use the same jig and tighten the string until the hooks feel like they are starting to bend. I suggest taking the clothesline hooks and bending them into a J shape first. Otherwise you will bend them for sure. And while it doesn't hurt the string it's pretty exciting when one pops off the hooks because the hook bent. ......... so I have heard.

[Significent]

nchunterkw: My clothesline hooks are 3/8" in diameter. I'm not sure they'll bend before the string breaks. What diameter are your hooks?

[vixenmaster]

Oh yeah 3/8" hooks will certainly bend, on my 4th one in past 2 yrs. I usually have to replace because the threads pull out hooks n nuts. I go thru several sets every yr

[Significent]

Amazing. Do you oil the threads a bit? I wonder what the breaking point is for a stock Matrix 405 string or what the max tension should be when stretching/serving. Has anyone used a torque wrench to try quantifying a good pre-bend torque?

I finished building my jig a little while ago. It's made of 2x6 and square steel tubing. It's open on top and the lower corners are braced with upright angled 2x6 as well. So it's pretty sturdy. It's kind of a hybrid between Don's 2x4 version and his all-steel version. I put a 3/8" turnbuckle in-line with the string so I have more flexibility and can use it for both short and long strings.

[vixenmaster]

Most of the modern materials usin 28 strands or more hit 3000 lbs strength & more

[Significent]

OK, so I put a torque wrench on mine. It appears that the hooks start bending at about 40 in lbs. (No oil on threads) Anyone else have a similar number?

[vixenmaster]

No have torque wrench, jus box end wrench. I use anti-seize on my hook threads.

[Significent]

I did a little looking around to find that the maximum recommended load on the 3/8" clothesline hook is 240lbs. That's probably a few pounds under where the hooks start to bend and not that much different than the bow weight.

[nchunterkw]

The hooks are a poor design for what we are doing. Clamp them
In a vise and beat them into a J shape. You can put more load on it by far. Also using torque is not an accurate way to measure tensile pull. The threads and lubricant play a big part.
If you want to do that I'd suggest attaching the hook to a threaded rod. Put the rod through the steel bar and through a spring on the outside of the bar. Put a stout washer and nut on the threaded rod. Now you can tighten the other end and see how much the spring compresses. You can buy a 312 lb/in spring at Grainger. Just look around. Those springs compress linerally so 1/2 in would be 156 lbs, 1 in would be 312 etc. This is a neat design and will give you an idea of tension but is it really not necessary.

You ain't gonna break a string either. As Mike said modern materials have breaking strengths around 90 to 130 lbs. multiply that by the number of strands and you come out close to 3000 lbs. I'm talking about Flemish strings. EL strings have 1/2 the strand count in the loops so the strength is 1/2. Still way overkill for our bows. Hope that helps.