"Burrs on the hub" sounds bogus to me.  Could be the case with a new hub, but burrs would be worn away with use.

It seems most likely that the hub was reassembled by "unskilled labor" (the new/careless guy in the shop) and he didn't notice that the hub holes are directional -- there is a countersink on one side of the hole and not the other -- or didn't understand how you put spokes in such a hub.

When the holes are directional, you put the head of the spoke on the non-countersunk side, so that the curve of the spoke mates with the smooth countersink.  Placing spokes the opposite way will result in the curve of the spoke being against the sharp corner of the hole (and a broken spoke).

To check this, look at any hole where a spoke is broken.  If the two sides the hole are different, the side with the smooth rounded countersunk shape should be matched with the bend in the spoke, and the head should be on the other side.

Another possibility is that machine spokes were used.  These spokes have a longer distance between the head and the bend, to simplify things for lacing machines.  But these are bad for hand lacing, as there is too much "lever arm" unsupported by the spoke hole, and the heads will tend to pop off.  If such spokes are used one must use small spacer washers on the head side to pull the bend tightly to the curve of the spoke hole.

Or, of course, they could be lousy spokes.

(If they were breaking at the rim end this would be due to the way the rim is drilled and possible missassembly placing left-facing drilled holes with a right-facing spoke, or simply spokes that aren't strong enough to stand up to the stress of being slightly bent at the nipple.)

Spokes keep breaking - bad hub or bad build?
When I click "add comment" on an answer on the Stack Exchange Android app, I get a comment box, but the "add comment" button doesn't go away. Instead, the "post" button comes up in another place.

Android 4.3 on Nexus 7 (2012 version) with Stack Exchange Android app v. 39.


