The drill whines to life!
A customer brought in a right crank from a SRAM Force crankset with a power meter attached.
They mentioned that they'd broken one of those bolts.
↑This one
The remaining 7 locations were already loosened, apparently.
When they applied the tool and broke it, they weren't tightening initially—
they were loosening when it snapped. At that point, anyone would have broken it,
like being the last peg in that "Trouble" game (the children's game where you pop pegs).
If the main cause was a sudden torque shift from galling at the thread,
then applying some penetrating oil like Laspene might reduce the probability of it happening.
But honestly, I don't think anyone can eliminate the possibility entirely.
Removed the 7 bolts and spider.
↑The break point
To prevent the drill from slipping,
I used a router made by Kiso Power Tools, sold under the Ryobi brand by Kyocera (→here)
to create a pilot hole for the guide.
Whirrrr!
The thread section didn't seem to have any seizing from rust or threadlocker,
so the broken bolt—now acting like a seized screw—rotated along with the drill bit
and drove further inside. Since it was already below flush anyway, the threads advancing wasn't a problem.
Either way, I can remove it with the seized screw extractor tool.
Recovered it.
Our shop normally sells individual bolts from this 8-bolt set,
but the distributor is currently out of stock and we don't have much spare inventory either.
However, we can manage a single bolt,
so I replaced the broken bolt with a substitute, re-tapped all 8 bolt holes,
applied grease, and torqued all 8 bolts home.
A customer brought in a right crank from a SRAM Force crankset with a power meter attached.
They mentioned that they'd broken one of those bolts.
↑This one
The remaining 7 locations were already loosened, apparently.
When they applied the tool and broke it, they weren't tightening initially—
they were loosening when it snapped. At that point, anyone would have broken it,
like being the last peg in that "Trouble" game (the children's game where you pop pegs).
If the main cause was a sudden torque shift from galling at the thread,
then applying some penetrating oil like Laspene might reduce the probability of it happening.
But honestly, I don't think anyone can eliminate the possibility entirely.
Removed the 7 bolts and spider.
↑The break point
To prevent the drill from slipping,
I used a router made by Kiso Power Tools, sold under the Ryobi brand by Kyocera (→here)
to create a pilot hole for the guide.
Whirrrr!
The thread section didn't seem to have any seizing from rust or threadlocker,
so the broken bolt—now acting like a seized screw—rotated along with the drill bit
and drove further inside. Since it was already below flush anyway, the threads advancing wasn't a problem.
Either way, I can remove it with the seized screw extractor tool.
Recovered it.
Our shop normally sells individual bolts from this 8-bolt set,
but the distributor is currently out of stock and we don't have much spare inventory either.
However, we can manage a single bolt,
so I replaced the broken bolt with a substitute, re-tapped all 8 bolt holes,
applied grease, and torqued all 8 bolts home.