Paging those good with rounded bolts - advice needed.

Honda CB400T oil filter cover bolt. Done up by previous owner - Hercules. It
was a bit rounded, now it's a bit more rounded. I've tried smacking it with
an impact driver but it's under the engine so I only have a few inches to
move the hammer. The bolt head is sunk into the finning so needs a socket.
It's a 12mm but a 7/16 won't tap on.

Any ideas on how to get the bolt undone?

John

 

To get more hammer swinging room:

1. fasten a strap to the bars and hang the bike from a tree or the rafters
of your shed

2. lay the bike on its side.

In a more serious vein, I would cut a slot in the bolt head with a cutoff wheel
in an angle grinder, and get it out with a large flat bladed hex shank screwdriver
bit.

 

I've got a set of these...
http://cgi.ebay.co.uk/290463114744

They kick arse at exactly this job.

 

Are you using a 6 sided socket or 12. If the latter, I suggest sourcing
and trying the former. ICBW but I don't think the impact driver will add
much if it's already rounded off. Different kettle of seafood of course
if it were a gouged screw.

 

<twitch> they look quite good.

 

WUN will be along soon to suggest a left-handed drill.

I first discovered the efficacy of arc welding something onto the bolt
head (assuming it's steel) when I couldn't remove the seriously rounded
and Mole-gripped oil filter cover bolt on my old XS750. This also assumes
that there's nothing delicate or flammable nearby. Kind of a last resort,
though.

 

Weld a socket head to the bolt, if there's enough clearance.

 

What a fantastic gadget. I'm going to order one. Thanks.

 

You arsehole.

*twitch*

 

Picture it. Bolt head, made apparently of furry brown cheese. Goes into a
steel threaded insert into a plastic thermostat housing. No resistance
even to a 6pt socket. Mole grips, no joy.

Got these suckers, put one on - no joy. Went down one size - and it just
unscrewed.

I was seriously thinking I was going to be breaking out the angle grinder
to get the head off, then praying the stub would wind out.

 

I wish I was on commission...

 

Even better a 6 sided "surface drive" socket. Halfords have them. I have
three in the most common sizes I encounter on SO Italian stuff 10,13 and
17mm. Good they are.

--
+-------------------------------------------------------------------+
| Pete Fisher at Home: |
| Aprilia Shiver Yamaha WR250Z/Supermoto "Old Gimmer's Hillclimber" |
| Gilera GFR * 2 Moto Morini 2C/375 |
+-------------------------------------------------------------------+

 

Jolly tempting but I wonder how often they simply allow you to shear the
head off the bolt. The Snap-On 6 sided flank drive sockets manage most
things.

Drilling down through the centre of the bolt first helps of course.

 

Haha. If I hadn't just spent £300 on tyres and batteries I would have
bought them too.

 

No...
Oh OK then....

 

Is that what I think it is: a self tapping socket?


And it covers some whitworth sizes too. Neat trick.

 

Indeed.

<fires up Amazon>

$39.98 shipped to me, ordered.

 

Oh, I wonder if they do a similar thing for allen bolts...

 

Can't see why they wouldn't work, if you get 'em snug enough - the
spirals taper, so as the socket's pulled in, it bites harder.

I'm _hoping_ they work, because I've got some furry brown cheese allen
bolts which are rounded out...

 

I think you've hit the nail on the head quite firmly there. You run the
risk of shearing the hex off and then having to resort to butchery to
remove the offending item. I wouldn't touch them with a shitty stick.