Spoke Pops Out of Nipple
 

Trying to bring a wheel up to tension. Spoke pops out of nipple. Sapim butted 2.0/1.8/2.0 with brass Polyax nipples.
Can't tell which is bad, spoke or nipple. Order a few more spokes and try again?

Just one.... or many?

I always build wheels with at least 2 spare spokes and more nipples. In a case like yours I'd try another nipple. If it works, I'd call it good and forget about it.

"Spoke pops out of nipple" Explain better please.
The first reading had me think the spoke was so long (or the rim flat spotted badly) that the nipple had to be so far threaded onto the spoke for any real tension that it extended above the nipple.
But on rereading I wonder if the spoke never engaged the nipple's thread and the nipple was just floating on the spoke.
Or is there another situation?

Belts and suspenders are a good idea when one no longer has a LBS they can walk to and get another part from quickly. Bad nipple threads do happen (I used to keep a non drilled and threaded nipple to show that mass production wasn't perfect). Back in the day we used to thread a nipple on each spoke sold to insure it all worked. The time to do that is pretty much not paid for these days. Instead people rely on assumed QC departments. Andy

Yes, tried another nipple and pop. Must be spoke. I always buy spare spokes and put the extra two on the chainstay. I will put a piece of tape on spoke to verify if its the same spoke if it pops again. Ugh.....

I would think it would be the spoke. Easy enough for them to get mixed up and put in the wrong box. 1.8mm spokes in 2.0 nipples will hold on til you up to over 50% tension then pop right off.

I will double check with micrometer. Good thought

The spoke had seated and I was winding them up one at a time. Checked tension and was still low, then PING!. This is new to me, never had that one happen. Its obviously a thread interface issue. Also, which is harder metal, the spoke or the brass? I assume the spoke, but if the thread is damaged none of that matters. And the nipples are 14mm so lots of engagement room. Bigger concern would be a bad batch of parts and this continues as I go.

OK, maybe it was me. I did the spoke calc repeatedly, compared several calculators. I see threads still exposed on the spoke as I am bringing up tension. I may be too short and the engagement pops as not enough threads engages. Oof......

Could be a case of garbage in, garbage out. Did you measure the hub and rim yourself, or rely on manufacturer's data? That can sometimes be way off in my experience. Case in point, just last week, I ordered a hub that the seller's data showed had 58mm hub flange diameter on both sides. When it arrived, I measured it at 45mm left and 49mm right. The CTF measurements were off as well. Not the first time I have found such a discrepancy.

I broke out the calipers, went through everything, its all the same as my original measures. A friend is a wheel builder, he said on occasion he will get some bad nipples that won't hold. I am going to grab a few DT nipples and retry the same spoke that popped. I also used multiple spoke calculators and found all to be within .5mm on size. Sigh.....

One rule of thumb I go by is that the threads should disappear into the nipple (or be very close to it) by the time you start developing torque on the nipples. Was that the case?

I just checked, and they are covered. I am at 17 on a Park Tool (?kgf) at the moment. I have done about 10 wheels since learning years ago, none of them had this issue. Frustrating

EH,
Not sure about your nipple length. I keep 14mm,16mm and 18mm in case I find a spoke not engaging properly. You might try a longer nipple and see if that helps. Smiles, MH Call me if you need one or two of the longer ones, 812-336-3283