[bxr140]

For whatever dumbass reason, I cross threaded one of the screws that secure my tank in the front (by the steering head--its an '01 F4i). To further ensure dumbass status, I snapped the screw while trying to remove it. Of course, it didn't break with much of anything sticking out of the frame--it was virtually flush with the frame.

I hit the raised nub that was there with an angle grinder to try and make it as flat as possible, but I can't make it completely flush with the frame, as the screw broke such that part of it that was below the "plane" of the frame came out too. So now when I try to drill a hole for an extractor, the bit just falls into that little depression (which of course is on the edge of the screw, not right down the center axis), then because the screw is harder than the frame, the bit wants to wander over and take out the frame.

Thoughts on what to do next? What I'm worried about is that if I even GET an extractor in there that it might not be able to remove the rest of the cross-threaded screw.

 

[erik996]

If you have a Dremel, use it. There are a multitude of attachments that will allow you to grind the top of the bolt however you want.

If you don't have a Dremel, GET ONE! It's an incredibly versatile tool.

 

[Pacifico]

Dremmel is a good call.

You'll prolly have to drill it out but check to see if EZ-out has a size to fit your screw. They work well.

Soak with penetrating oil if you have any. WD40 does little here but silicon does work somewhat.

To help keep the bit centered first drill through a 1X1 pc of wood and guide the bit with the wood while it's turning.

Perhaps you can cut a slot in the remaining screw end and get a slotted screwdriver in there - prolly too much torque to overcome given you broke the head off but I'm having trouble visualizing the exact situation.

Or any combination of the above. Good luck to ya.

Pacifico

PS; This ranks about a 2 on the Pacifico Dumbass scale. I've had 11's so keep trying :waytogo:

PPS: You guys have the same avatar? WTF? :crazy:

 

[wargame1]

I think you should take it to a local shop.. have them drill the screw out and re-tapp the hole.. It might cost you a little cash.. but its more than likely better than most ill-equipped home jobs. Just my $.02.

 

[NegativeGs]

How bad did you mangle the end of the bolt when you tried to drill it out? If it isn't too bad, use a sharp center punch to dimple the end of the broken bolt so you have a small spot to hold the bit while it gets started.

Get a couple of LEFT hand drill bits. Start with a small one until you have drilled into the bolt a small amount so a larger bit will have a guide. Usually the drill bit will walk out the bolt once it generates some heat. Go easy with the smaller bits so you don't break one off. Take your time and go slow.

 

[TravellinJones]

This screw, does it go into the aluminum frame? If so, there's probably a welded or captive nut there which will need repair. Or maybe the whole thing is replaceable without removing the broken screw.

Just thought you'd want something else to worry about while you work. :laugh:

 

[south]

I second Negative G's approach. Dimple the center of the remains of the bolt with a punch and start with a small bit to ensure that it doesn't wander. The left-turn bits are also a good idea, but if unavailable, use standard bits--don't put too much pressure on them when drilling--and an easy-out. Judicious application of heat DIRECTLY onto the broken bolt can work very well.

I don't know how much success you'll have, considering the bolt was cross-threaded/jammed in there tight enough to snap the head instead of backing out, so:

Worst case, if the bolt won't come out, as long as you've got a centered hole, you can carefully drill out the body of the bolt until the width of the hole is just inside of the threads, and then run a properly sized tap into the hole to ream out the remains of the bolt while saving (and repairing) the threads in the frame. Just be patient, make sure you punch a good dimple in the exact center of the bolt, start with a small bit and gradually move up in size, and good luck. :waytogo:

 

[Dunno]

Lots of good advice so far.

To add to what has already been said, if you center-punch the broken screw, consider using a spring loaded "automatic" center punch. That way you can just put the point on center, and push down. There's been times when I've used a hammer and punch and just made more problems for myself, if you know what I mean.

Once you start drilling, be sure to go easy on the drill bit. That means going slowly on the drill's speed and resisting the temptation to push down too hard. Lower the "feed and speed", as my sheet metal instructor once said. You'd be surprised how well a drill bit can cut through steel at a very low r.p.m. Also, put some kind of cutting lubricant on the drill bit before you start. That will help prolong its life. There's lubricants made for this purpose, but I've used engine oil and it worked just fine too.

In my experience, once you see the first wisp of smoke from a drill bit, it's done. Get another and keep going.

Starting off with a smaller diameter bit and working your way up is a good idea, too. I find it all depends on the diameter of the broken fastener. If it's something small, say like a #10 (around 3/16"), I'll just go straight to a 1/8" bit, drill the hole, and use the extractor from there.

 

[blkduc]

Actually, heating the bolt directly is wrong. Always heat the area around the bolt. When you heat the area, you are exciting molecules and expanding them. You want the area around the bolt to expand not the bolt itself. If the bolt expands, it will be even harder to remove. Trust me on this. I've done this too many times.
Your best bet is, start with the dremmel. Whether you notch it(for screwdriver), grind it flat(to drill into), or just grind out so much bolt material that you can easily pick out the remaining threads(be careful not to grind too much or you will trash the threads). This is the best place to start. If you do damage threads beyond repair of a tap, you can use a helicoil or even better, a threaded insert(depending on the material you are going into)pm me for details on this if needed. One thing that I didn't catch, how many threads are remaining? What are you threading into, welded nut?

 

[south]

[ QUOTE ]
blkduc said:
Actually, heating the bolt directly is wrong.

[/ QUOTE ]

Generally speaking, I agree. But, as you can see from BXR's original post--and in answer to your question,

[ QUOTE ]
What are you threading into?

[/ QUOTE ]

--the broken bolt is stuck in the aluminum frame. Hence I recommended that he heat the (harder) bolt which will transfer the heat to the (faster/greater expanding) aluminum with less risk of damaging the frame at the point of heat application--i.e. the bolt will withstand the direct application of heat/flame better than the aluminum would, but, the aluminum will still expand sooner/more than the steel bolt. This thought, and the fact that the steel bolt will provide fair warning by showing it's relative temp. via a readily observable color change whereas aluminum remains visually unchanged until--too late--it turns shiny as it melts, is all part of my recommended "judicious" application of heat. :waytogo:

 

[f2benny]

I once snapped a mirror bolt off in an upper fairing with nothing exposed. I center punched the remains, drilled out the direct center to about 1/4 inch depth and used a screw extractor. Should work here. Worst case senario is to snap off the extractor since they are very hard steel. Use lots of penetrating oil on the bolt too help as well as some heat on the frame.

 

[bxr140]

Thanks for all the suggestion Guys (and Gals?).

Looks like I really just need to be a little more patient and a little more deliberate with my actions. I'm used to getting trashed bolts/nuts off from many years working on cars, but they're usually bigger. This one is also the most difficult and awkward. Its an M5, BTW. Probably .8 thread. About equivalent to a #10. Any reccomendations on drill bit size? How small is too small for a drill bit to be effective?

This is also the first time I'll have to pull a cross threaded screw out with nothing exposed to grab onto. I'm usually smart enough to stop before things get this bad. I actually went down almost all the way, decided it was cross threaded, and snapped it while tring to REMOVE the screw.

 

[Dunno]

The extractor I use for #10 screws requires a 1/8" hole. I've used #30 drill bits with these extractors, but #30 is actually a tad bigger than 1/8", so I only use them if it's a low stakes kind of situation.

If you can get a good, clean center punch on the broken screw shank, you could start right off with a good, sharp 1/8" bit. Drill a little, stop and check to make sure you're still on center, then drill a little more.

Like I said before, slow and sure does it. The drill bit should be able to do most of the work. If you find that you have to push fairly hard on the drill to get anything to happen, the drill bit is probably pooched.

I've noticed when everything is going my way, the drill bit cuts out long ribbons of metal from whatever I'm drilling. If it's cutting down the material in chips or a powder, then the bit is probably getting dull and won't be doing anything at all pretty soon.

 

[NegativeGs]

Is it possible to get a pic of the broken off screw? Is the threaded insert that this screw goes into exposed on the other end or is it a welded in insert that is enclosed in the frame? What is the thickness of the insert? If the diameter of the insert is large enough and thick enough, you may want to consider drilling though it with a drill bit a bit smaller than the screw and tapping it out for the next larger size. If the screw is steel and the insert is aluminum and the screw was cross threaded, the threads in the insert are probably mangled.

 

[south]

As far as drill bit size, start as small as you can, definitely < 1/8, so the bit will stay in the dimple you punch in the bolt shank. All you really have to do is get the small bit(s) to open the dimple/hole equivalent to their width before moving up to the next biggest bit; you don't need to worry about drilling very deep with the smallest bit(s).

As I mentioned, and as you hint, I don't think an extractor/easy-out will remove the bolt since it jammed tight enough to snap the head when you tried to remove it, so it's really important to drill in the exact center of the bolt shank, which will let you drill out all but the bolt threads and then run a same size and thread tap into the hole to ream out the last remains of the bolt and repair the bolt hole threads.

If things just aren't working out, you can always drill out the whole mess, take the bike to a (aluminum) welder and let him/them weld up the hole--fill it in completely--then you can just drill and tap a fresh hole, and it'll be good as new.