Any tips for retrieving a snapped screw from my frame?

[bobbys beard]

Just managed to snap a screw head off when tightening my bike rack and wonder if anyone has any tips for retrieving it, (before I end up covered in various glues and swearing a lot....) 

[mbattisti]

is any of the screw protruding out the backside of the hole?  If so, you can try continuing to screw it all the way through and out with some vice grips.  First cleanly remove any remaining part of the head (grind, file, or dremel-cut off wheel).  What type of material is the frame?

[bobbys beard]

Unfortunately not, it's quite clean to the frame. (aluminium). I wonder if I have to find a strong glue and stick it to something that I can turn it out with....

[aggie]

Broken screws are "common" in auto repair so there are a few devices available that will allow you to retrieve it.  Most auto parts store will most likely have one you can purchase.  Sears may also have them in stock. 

[DaveB]

Broken screws are "common" in auto repair so there are a few devices available that will allow you to retrieve it.  Most auto parts store will most likely have one you can purchase.  Sears may also have them in stock.

They are called EZ-Outs but require drilling a pilot hole in the broken stub to let them work.  That's not easy with a typical M5 bolt. 

[bobbys beard]

Thanks. Yeah, I think drilling a hole would need the tiniest bit and a hand steadier than mine, but maybe a drill could turn it...  I live a long way from anywhere that might sell something like that, so if I can't get it out, I'll ask a car mechanic

[DarrenBnYYC]

I have broken a couple M5 bolts by over-tightening them. What worked for me is to drill out a small hole (start with the smallest drill bit you can find and then slowly go bigger to expand the hole). Then I used a 'poor-man's EZ-Out: I just gently tapped in a small Torx head with hammer to get the leverage to back out the broken bolt.

[paddleboy17]

Thanks. Yeah, I think drilling a hole would need the tiniest bit and a hand steadier than mine, but maybe a drill could turn it...  I live a long way from anywhere that might sell something like that, so if I can't get it out, I'll ask a car mechanic

Any decent hardware store should be able to sell you an easyout.  They are pretty common.

[sjstwrt]

first, toss a lil bit of tri-flow or some kind of anti seize around it.
try taking a pick and trying to catch the edge of the screw and scrape the outer diameter of the snapped bolt in the direction it turns out  (ccw i think).

try taking a screwdriver or something like that and screwing outwards while putting pressure forward on the bolt, like there head was still there.

other than that an ez out is the best solution. ive done a bunch of wrenching and i find a pick works fine unless the bolt is seized.

[PeteJack]

I've found it almost impossible to remove a broken screw and leave a threaded hole that you can use but by all means try screw extractors etc.  There are even drills with flutes going the wrong way that you run CCW just for extracting screws. The only ones Ive found are here. Remember to run your drill backwards with these.

There are devices known as Helicoils that require a hole bigger than the screw. Helicoils are inserted in the oversize hole to give you the original female thread. Drill out the screw very carefully using a center punch to mark the center of the screw.

Helicoils are very good and will be in fact stronger than the original. (Boeing use them for stronger fasteners on new parts). The only snags are expense and there's a smidgin of know how to inserting them, you may have luck finding a local auto repair place that will do the whole job for you for about the price of a kit that you are unlikely to need again

[staehpj1]

I have had good luck using an abrasive cutoff wheel on a dremel to cut a slot and then remove the screw with a screw driver.   I have done this successfully quite a few times.

[hon_cho]

If you are fortunate enough to have room to use a drill, you need to purchase a left-hand (reverse) drill bit and attempt to drill it out.  Left hand drill in reversible drill running in reverse.  It has been my experience that unless the broken fastener is seized in the hole,  the reverse bit will easily remove the fastener. 

Here's a link to a set that I have used with success on broken fasteners.

http://www.amazon.com/Irwin-Cobalt-64-Inch-Assortment-30520/dp/B0002NYBJG

If the link doesn't work,  it is an  Irwin 5 Piece Left Hand Cobalt 5/64-Inch to 19/64-Inch Cobalt Twist Drill Bit Assortment (30520)   

I believe that Harbor Freight Tools also carries a left hand drill bit set which is probably less expensive. 

Good luck. 

[misterflask]

My go-to approach is to use a finely-pointed center punch.  Angle it about 30-45 deg from vertical and start at a point about halfway between the center and edge of the screw.  Tap the punch lightly in the desired direction.  I have rarely had to fall back on a backup plan when using this method.

An important point is how the bolt broke off.  If it broke from inadvertent overtightening during installation, you will probably get it out one way or another.  If it broke off because it was corroded in place, you will not get it out and the solution will be along the lines of drilling and rethreading.

For the ridiculous high-tech approach, you can scout around for a machine shop with a portable EDM http://edmtechcenter.com/index.php/products/hole-drilling/portable-edm-tap-remover.  An EDM can burn out the body of the screw and the screw helix can then be picked out.