Wheel Building - Spokes Question

After messing up my last rear wheel in a worrying incident with a 4x4 (she was on the phone), I decided to make my own new wheel.
The exact spoke length I needed was 293.6, the closest my LBS had was 296mm. Sheldon says "Generally, I round upward to the nearest available larger size", so I hoped they would be near enough.

I've built the wheel, but unfortunately - being too long - some of the spokes have extended past the thread, so the nipples are screwing a fair way into the unthreaded body of the spokes.

Is this just plain dangerous, or will they hold no problem?

I've given it a quick test ride and it seems to be strong.
Although I've been careful about spoke twist and have stress relieved the spokes extensively, it's still pinging a bit. Is this normal for the first ride on a newly built wheel?
Given it a few skids with no trouble, but the thought of it collapsing in traffic makes me want to double check.

de-lace and get spokes that are actually the right size. Sounds like you need 294mm. mm's matter

I would guess that you'd find it really difficult to screw the nipples past the end of the thread.

Either:

• you have screwed past the end of the thread and you've stripped some of the threads from the nipple (softer than spokes so thhats where the threads get stripped).
  
• most nipples have an unthreaded portion of about 2-3mm inside the spoke end and you may have just used up this unthreaded portion without doing any damage.
  
  

If you have stripped the threads a littl, you are more likely to have the rest of the thread stripped than you were, but there may still be about 8mm of thread gripping the spoke and that may be enough if you're not a heavy rider. All depends how many spokes you have. 32/36, may be ok, less than 32 I'd be starting again with the correct spokes and new nipples.

If you have any spare nipples, check inside the end to see if they have an unthreaded recess.

The nipples are 12 mm, first 4mm are unthreaded. 32 spokes, and I'm a fairly light rider.
I've compared some spares and I reckon I have at least 5 mm still threaded on the worst of them. They're holding their tension, so I think it will be fine temporarily until I can rebuild it.

Thanks for your advice guys.

Yeah, you're going to need to rebuild these I'm afraid. Personally I round down spoke size, and never more than 1.8mm. Spokes stretch slightly at first, and when you retension them the problem will worsen.

and don't worry about the pinging, it is just everything seating itself and would happen even if you stress relieve the spokes extensively.

does anyone know on the internet where i could get around 36 of them. i dont really want to buy 100 and my local bike store doesnt stock them because they are an unusual size and he doesnt really want to get a hundred either.
cheers

also how many mm can you be out. i have found some at 278 so could i use those?

278 will be fine, you'll just have to tighten down the nipple's a bit more and make sure that your rim tape is good and tuff.

Would have put this on the any question answered thread but Ive been asking too many questions on there recently. This thread seems pretty appropriate too.

Question is, why this:

using double butted spokes throughout except on the drive side rear where Sapim 'Extra Strongs' are utilized

From the spa cycles website. The wheels in question are 36h Sputniks on deore xt.

most of the stress is on the drive side so stiffer /stronger/heavier spokes on that side will make a stiffer/stronger wheel.

Ive been a div. For some reason I thought that sapim extra strongs werent double butted, hence me being confused.

Cheers Dylan