LCGB Forums

Morning all,

Was stripping the mag flange, and had not done one for many years, and put bolts in the wrong holes to extract (doh) and tightened one too much that it snapped.
Yes, what an absolute fanny I hear you all say.
Tried to get the broken bolt out (once the housing was correctly removed), but no way. Tried drilling it out to then use a stud extractor but the drill bit snapped in the bolt, so that is now stuck!
Only way it seems that I can get this out is to weld a nut to the broken bit and get it out that way.

Therefore my question is to you all - Can I get away without one of the stator bolts or do I need to ge it sorted?

Your help is most appreciated.

John

Why not drill and tap a new fixing near to the damaged one but watch what's behind it. You're never gonna get the broken drill out unless you take it to an engineering company to spark erode broken drill out. Just my opinion mind.

May I presume two things from your description?

The first is that the bolt that is broken is in your crankcase, not the magneto housing.

The second is that perhaps you are not an engineer. That sounds patronising, but it’s not meant to.

Personally, I don’t have a lot of faith in stud extractors as I’ve seen them break, too.

The advice you’ve already received is sound. A spark eroder will do the job. Finding somewhere to do the job on a complete crankcase might prove difficult....

However, if it were me, as a reasonably competent engineer, I would try, or get somebody confident enough to try, to ‘break’ up the remnants of the broken drill in situ. That is, with a hardened punch small enough attack the drill remnants such that they break up more into little bits to then be extracted piece by piece using air blasts, magnets et cetera.

Then, once removed, carefully drill the hole bigger & bigger a little at a time, remaining concentric & square.

Then, when the hole you have in the bolt (concentric & square) is about Ø 4.5 mm maximum, take your remaining stud extractors & throw them over the nearest hedge.

Using copious amounts of penetrating oil, possibly heat & cut up hexagon keys/screwdrivers force something into the hole &, if you are lucky, it should unwind.

I hope that helps. It’s worked for me more than once.

You will also have an air/oil leak if you run with only two. I know as I have just done the very same thing!
Simon

like monument 7 said, if you dont want to srip your engine fully down, dont have any engineering facilities, then speaking from an engineering perspective drill & tap a hole close to the original one & fettle your stator to suit, but you do realise that this would only be a temporary measure as it could lead to future problems.....

Thank you for your responses.
Correct, I am no enginneer.
I shall take all on board and get the offending broken stud/drillbit removed.

I will let you know how I get on.
And yes, I will read my Sticky book in future before starting anything again.

Regards

John

Hi again.

Surely, the suggestions to drill & tap 'alongside' must mean that the crankcase (because that is where the broken fastener/drill has to be) would be compromised, or am I missing something? The six stud positions are all dictated by the geometry of the stator & mag flange which align with the crankcase holes. The M6 crankcase holes are central within little cast bumps, aren't they? There isn't really an 'alongside' to use, is there?

Am I being thick again? Most likely!

Warkton Tornado No.1 wrote:Hi again.

Surely, the suggestions to drill & tap 'alongside' must mean that the crankcase (because that is where the broken fastener/drill has to be) would be compromised, or am I missing something? The six stud positions are all dictated by the geometry of the stator & mag flange which align with the crankcase holes. The M6 crankcase holes are central within little cast bumps, aren't they? There isn't really an 'alongside' to use, is there?

Am I being thick again? Most likely!

Read the part of my post where I said watch what's behind it. It's a quick fix to get him going but could possibly be long term if there's enough meat to tap in.

Hi.

The mag flange is effectively sandwiched between the crankcase & the stator. IMHO, to do as suggested would result in the ovalising of the hole in the mag flange & a hole in the crankcase that would break out @ one side of the cast 'bump' which would take a fair bit of welding & dressing to repair.

If my interpretation is correct & that is what was meant as a last resort, then I was being thick in not visualising this bodge properly, sooner.

Let's hope that the broken screw/drill bit comes out easily, eh?

Hi

My advice would be, in all honesty if you've snapped a stud off & you've then snapped a drill off trying to get it out then perhaps your best, cheapest & easiest option would be to get someone else with engineering skills to get it out/ repair it for you. Have you contacted any scooter shops or engineers for a price? Better to get it sorted now before any more expensive damage is done.
Not having a go, we all make mistakes, I know I do...

Mark.

I have to agree with the other posters.
It might sound harsh but given the mess you have managed to make of it so far ...how much more damage to your crankcase are you willing to risk before it becomes unusable ?
I don't understand peoples reluctance to use an engineering shop to do this work .Whats the most it could cost ? £15 to £20

There is only one tool that is capable of removing a stuck or sheared stud or bolt providing there is still 1/4" or more of the stud showing and that is a pair of Stilsons.
If you can get Stilsons to grip the stud then the more pressure you put on the stilsons the tighter it will grip the stud or bolt.
You'll need to use a 12" or possibly 8" pair of Record Stilsons .

The other option is to weld a nut to the top of the stud and then use a spanner to remove the broken stud

The method needed to drill out a sheared stud or bolt is to start with a 1/16! drill bit to drill a carefully positioned pilot hole in the exact centre ,which will guide the next size drill bit .This is best done with a pillar drill .

Agree with the machine shop option but drilling isn't as he says he's broke a drill in it.

monument7 wrote:Agree with the machine shop option but drilling isn't as he says he's broke a drill in it.

I was not suggesting that the po attempts to drill out a drill bit simply relating the correct method for his and others future reference