Help! Threaded a bolt on the head!

Help! Threaded a bolt on the head!

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Discussion

beanbag

Original Poster:

7,346 posts

248 months

Saturday 29th September 2007
quotequote all
I've been upgrading the disc rotors on my stumpy to a 203F and 185R combination, and I managed to thread the head of one of the rotor bolts while tightening it up. irked

It's not a huge deal to be honest as it's nice and tight and I have no plans in the near future to remove it, however at some point I'd like to replace the bolt with one that isn't threaded.

So my question is how do I remove it? I've got to be relatively fragile as I can warp the disc and that's the last thing I want!

Ideas I came up to remove it include:

1) Jamming a bigger head into the bolt but risk damaging the disc

2) Removing all the other bolts leaving the threaded one and shuffle the disc from side to side eventually loosening the bolt.

3) Doing what I did with my motorcycle and welding a bolt on top of the head of the threaded bolt and then removing. (Don't have a welder, and it's a bit extreme in IMHO).

So are any of these ideas worth trying or should I try something else?

Ta! smile

Rednut05

9,173 posts

220 months

Saturday 29th September 2007
quotequote all
A: Cut a line through the middle of it with a hacksaw. This then turns it into a flathead screwdriver job.

B: Drill it out.

C: Mole Grips.


GreenV8S

30,463 posts

291 months

Saturday 29th September 2007
quotequote all
When you say you've threaded the head, what exactly do you mean? Is the damage to the thread itself, or to the the bolt head machining that your spanner/screwdriver/key engages with?

mk1fan

10,648 posts

232 months

Saturday 29th September 2007
quotequote all
I'm with GV8. If you threaded the bolt it wouldn't be tight at all, it would be loose. When you thread a screw / bolt you shear off the spiral thread on either the bolt or in the nut / housing.

If you chewed up the head of the bolt then that is a different problem. If this is the case then you may find that you can remove the bolt quite easily as you've chewed the head in the clockwise (tightening) direction and so there maybe sufficient material left to undo it. Failing that cut a slot in it and use a flat bladed screwdriver to remove it. Following that a new bolt of the same size will screw back into the hub.

beanbag

Original Poster:

7,346 posts

248 months

Saturday 29th September 2007
quotequote all
GreenV8S said:
When you say you've threaded the head, what exactly do you mean? Is the damage to the thread itself, or to the the bolt head machining that your spanner/screwdriver/key engages with?
It's the head of the nut I've threaded. It uses a star shaped allen key style fitting and I just over did it.

I'll try rednut05's idea. Lucky a bought a hack-saw the other day! biggrin

Ta!

GreenV8S

30,463 posts

291 months

Saturday 29th September 2007
quotequote all
mk1fan said:
If you chewed up the head of the bolt then that is a different problem. If this is the case then you may find that you can remove the bolt quite easily as you've chewed the head in the clockwise (tightening) direction and so there maybe sufficient material left to undo it. Failing that cut a slot in it and use a flat bladed screwdriver to remove it. Following that a new bolt of the same size will screw back into the hub.
yes Also make sure you use a good quality hex drive bit not just any old cheap and nasty Allen key.

mk1fan

10,648 posts

232 months

Sunday 30th September 2007
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beanbag said:
It's the head of the nut I've threaded.
Pedant mode. You haven't 'threaded' the bolt. You've chewed up its head.

It's quite a common thing to do with both the Torx and Allen bolt heads. Disc bolts don't need a lot of force to remain tight - about 5Nmm irrc - litterally just a nipping when first tight. The bolts should have threadlock on them which will keep them in place.

Trooper2

6,676 posts

238 months

Sunday 30th September 2007
quotequote all
Stripped out the head, now I get it.






don't mind me it's 5:27 AM and I'm an icky American.