I was tightening the rear axle of my MTB with a torque wrench (1/4" bits) and accidentally cranked past the click without noticing. That left the axle seized extremely tight and snapped the 5mm bit off inside the axle head. It's a Newmen thru-axle.
That first broken piece was sitting loose enough that I could pull it out with a magnet. I then grabbed another 5mm bit (apparently a lower quality one, from a discount store) to try to loosen the axle, and that one snapped off too. This second piece is jammed absolutely solid and won't come out with anything.
As far as I can tell there is nothing to loosen on the other side. Just a smooth cone shaped tip, no hex, no flats, nothing to grip. The only place you can turn this axle is the hex socket where the broken piece is now stuck.
What I've tried so far:
- Magnet. Worked on the first piece, this one won't budge.
- Center punch and small taps to walk it counterclockwise. Nothing.
- Tapping directly on the broken piece with a hammer, trying to drive it further in. The axle is hollow so in theory that should be possible. Nothing.
- Cutting a small slot into the piece with an angle grinder so I could tap it around. Nothing.
- Trying to pop it loose with an awl. Nothing.
- Drilling it out. The broken piece is hardened steel and my HSS drills just skate off without biting.
I've called three different bike shops and none of them really saw any options over the phone. One of them did say I could bring it in and that they like a challenge, but I suspect that could get expensive fast.
I've seen diamond drill bits exist and I'm wondering if that's worth a shot before I go any further. Has anyone dealt with this before? Photos attached of the axle head with the stuck piece in it and the smooth cone shaped end on the other side.
I couldn't get the cap on the cone side off either, I have the impression it holds something of the derailleur in place.
by Ok-Echo-8213
26 Comments
Flat screwdriver hammered into the remainder of the hole would be my first try.
sorry i have no advice and i wish you the best but that is impressive.
if you want another DIY option search for ” Hex Key Wrench Set for Damaged Fasteners” or epoxy something in there that you can turn [https://youtu.be/jmvIsJwOVMo?t=257](https://youtu.be/jmvIsJwOVMo?t=257)
or take it into a shop.
Drill it out. Just make sure your drill bit size is smaller than the 6mm hex so you don’t damage the axle.
Well you are right the cap on the cone side holda the derailleur in place.The little screw doesn’t look beat up so just use a bit or screwdriver that fits exactly and turn it slowly with force inwards. If you remove the cap you could get a better look and grip at the axle (I’m sorry I don’t really get where an how its stuck) Looks like a cube isn’t it?
It’s time to drill. And then plan on using an EZ Out
Cobalt drill bit, drill out Allen key, and use an easy out. Start with a smaller bit, with a bit of luck the heat from the drill might loosen the stub of the Allen key and you don’t need to ruin the axle, if not, drill it to say 8mm and use a big easy out to get the axle out.
If the allen socket on the axle is still kind of not fucked, get some Vessel Brand Rainbow Allen Keys.
They’re the best keys I’ve ever used by a big margin.
so your options here are grim. my absolute top advice would be to take it to the bike shop that likes a challenge youve got a carbon frame and its better for them to have ago at it then you. That being said, here are your options:
-hammer a flat head into whats there and turn it out *BRACE THE OTHER SIDE OF THE AXEL AGAINST SOMETHING SO YOU DONT STRESS THE REAR TRIANGLE AND CRACK CARBON*
– punch a small dint into the head of the bolt, off to the side, drill a small recess into that and use a drift or punch to drive the both round slightly and then go back to the above option because it will stress the carbon less.
– set of locking vise grips on the cone end locked tight and maybe file some small flats on to grip onto, turn it back ever so slightly and then go back to option one again one its not locked down as bad.
-buy some better drill bits, drill through the snapped hex, start with a small bit and work up, and then get some bolt extractors and turn one in and turn the bolt out.
-last one is pretty grim, get a reciprocating saw and very carefull cut the axel frim the inside of the drop outs, maybe even sacrificing the cones for the hub. but thats a grim option as a last resort because after that youve still got to get the head out, but you may be able to then unbolt what it bolts into and just replace them
Get a cobalt drill bit on the job
Drill and an ez out. A good bike shop should do that for you no problem.
The hex driver is stuck? Thats the hardened bit? If so getting that out is job 1. A carbide burr on a rotary tool (dremel, die grinder, etc) could do the trick in combination with a punch.
Once out I’d first try a bolt extractor like the Milwaukee M2 set. They have a drill on one side to size a hole and the other side has the removal part. If this doesn’t work, try a left hand drill bit to drill it out.
Wtf 3 Bike shops and no one can drill that out for you? A real bike mechanic shouldn’t have a problem with that at all. I assure you, you’re not the first person to have this problem.
It’s a long shot but you could try this – Easy Out Bolt Extractor Set, 6Pcs Water Pipe Remover Damaged Screw Bolt Extractors Set, HSS Damaged Screw Extractor Bolt Stud Remover Set Thread Broken Stud with Storage Box for Household https://amzn.eu/d/0cVm1Kk2
How about drill a couple of pin holes into the axle head and use a pin spanner to remove? If the axle is very very stuck it’s unlikely to work, but it’s another alternative.
I was able to use an angle grinder to create a recess for a fat flat head screwdriver, it worked really well.
The extractor bits were eating the bolt and nearly chewed on the carbon.
Bring the bike to a local machine shop. They’ll be able to remove it.
Try to drill out just the broken hex piece, then hammer in torx head. I had the same problem and that was the solution.
(Carefully) drive a quality torx bit in there and try to get it to catch.
Stop using cheap tools and bits. They are too malleable and these issues are the result.
You know what might work? Drill two holes for a pin spanner. You may have to make your own pin spanner because the Park one likely wont fit.
Head to YouTube. See what others have tried.
How did you manage to do so? Thru axles only need a certain amount of torque…
Alternate idea, hacksaw between the hub and dropout. Basically cut through the end caps on both sides. The thru axle will be ruined but it already is. Then get new end caps for the wheel and hopefully without tension it’s easier to remove the bad thru axle.
Grind, file or saw off the cone on the Drive Side, then center punch it and drill out the threads on the drive side. Go up in drill size in small increments. Maybe you’ll get lucky and the drill will unscrew the axle. If not, drill until the threads are gone, then tap it out with a hammer
Nice bike shops…
Happy new bike day! (anticipated)
Use a stripped screw removal bit. If that doesn’t work, use a high speed rotary tool and a diamond wheel to carve a slot for a screwdriver.
Take it to an auto shop. They’re actually mechanics. Lol. Alternatively, a machine shop would have that out just as easy, but the turn around time would probably be greater.