Headley Posted July 23, 2008 Report Share Posted July 23, 2008 (edited) The other day I was tightening up a maggy bolt and it snapped, and part of it has been left inside the hole (I wasn't over tightening it). The problem I have is that the top of the bolt is below the top of the threads. I know it will have to be drilled out but I'm unsure of which size drill bit to use? I'm planning on helicoiling the hole afterwards. Edited July 23, 2008 by Headley Quote Link to comment Share on other sites More sharing options...
Z o o !! Posted July 23, 2008 Report Share Posted July 23, 2008 start with a tiny drill bit just to give you a pilot hole, it will have to be dead centre though then once you have the pilot hole just go up on drill sizes until its out, id imagine itl be 4 mm or 5mm Quote Link to comment Share on other sites More sharing options...
Headley Posted July 23, 2008 Author Report Share Posted July 23, 2008 start with a tiny drill bit just to give you a pilot hole, it will have to be dead centre though then once you have the pilot hole just go up on drill sizes until its out, id imagine itl be 4 mm or 5mmcheers for that Quote Link to comment Share on other sites More sharing options...
Jitters Posted July 23, 2008 Report Share Posted July 23, 2008 Another option is buy (or borrow) a bolt extractor. Looks somewhat like a tapered drill bit - and the grooves go opposite. Not very expensive, I'd say. Start with your small pilot hole like zoo!! suggested and get it as close to center as possible. No need to drill much. Put the tip of the extractor in there and twist it back out. If the extractor doesn't bite, you may have to drill a bit bigger pilot hole and try again.If the bolt isn't in there really snug, you can sometimes get away with drilling the pilot hole and getting a small Phillips head screwdriver in there and backing it out.You shouldn't have to retap the threads or helicoil anything if you go this route. I use bolt extractors all the time on rusty engine and auto bolts with great success. Good luck! Quote Link to comment Share on other sites More sharing options...
tris Posted July 23, 2008 Report Share Posted July 23, 2008 (edited) There's nothing holding the bolt tight. So drill it with a small dril piece, and then if you shove a small screwdriver or something into the hole it should just unwind. I did this with the fly bolts in the front of my bike wheel.Oh and don't bother helicoiling it because there's no need. The threads are still good, right?? Hope this helps Edited July 23, 2008 by tris Quote Link to comment Share on other sites More sharing options...
Headley Posted July 23, 2008 Author Report Share Posted July 23, 2008 Ok i'll try what tris and tappets have said tomorrow. I think the threads will still be alrite. Quote Link to comment Share on other sites More sharing options...
Jake Beach Posted July 28, 2008 Report Share Posted July 28, 2008 Yer start with a tiny one and biuld it up to a bigger one. Or if your frame has a disc mount put a disc on Quote Link to comment Share on other sites More sharing options...
austen Posted July 28, 2008 Report Share Posted July 28, 2008 Or if your frame has a disc mount put a disc onFor a start he woud have to have a disc hub aswell, and then he'd have to go buy a disc, so why bother with that when you could do a 5 minute drilling job?Yeah what tappets said sounds spot on Quote Link to comment Share on other sites More sharing options...
BenLeacock™ Posted July 28, 2008 Report Share Posted July 28, 2008 Danny did this a while ago, he had to cut abit of the mount and then use washers, pritty sure there was no other way it was coming out easy !Also sure he snapped a dimond drill piece trying! Quote Link to comment Share on other sites More sharing options...
grant_hundley Posted July 28, 2008 Report Share Posted July 28, 2008 just drill and helicoil it, probably easiest apart from the extractors Quote Link to comment Share on other sites More sharing options...
StevenJJ Posted July 28, 2008 Report Share Posted July 28, 2008 When this happened to me i just filed away a small bit off the top of the mount and then turned the bolt out with a pair of pliers. The mount was still fine to use after. Quote Link to comment Share on other sites More sharing options...
forteh Posted July 29, 2008 Report Share Posted July 29, 2008 Whats the screw made from? If its a decent high tensile allen screw then good luck trying to drill it, if its a normal steel cheese screw used on bikes then you should be ok. If its an aluminium screw that magura used to use then you can probably fart it out of that hole Remember if you do decide to drill it, centre punch the snapped end of the screw first, use a small drill (about 2mm) and steadily drill the bolt out, its vital you get the hole bang in the middle otherwise you will bugger the threads and definitely need a helicoil - it is possible to reclaim the threads without helicoiling The moral of the story is you need to learn how to use an allen key Quote Link to comment Share on other sites More sharing options...
Headley Posted July 29, 2008 Author Report Share Posted July 29, 2008 The moral of the story is you need to learn how to use an allen key Quote Link to comment Share on other sites More sharing options...
steve-winder Posted July 30, 2008 Report Share Posted July 30, 2008 Danny did this a while ago, he had to cut abit of the mount and then use washers, pritty sure there was no other way it was coming out easy !Also sure he snapped a dimond drill piece trying!I'm not suprised he snapped a diamond drill piece, diamond doesn't cut metal.The best drill pieces to use are either tin or titanium nitrate coated bits. Hard as hell and make light work of even the hardest stainless steels.when it comes to removing bolts i have used the same technique every time. Drill a small hole in the centre of the bolt, then tap a tight fitting torx bit into the hole. the bolt will usually then unscrew. If not, there are tools available for the job called stud removers. Yet again you need to drill a hole in the centre of the bolt but stud removers use a left handed thread to screw into and remove the bolt/stud.steve Quote Link to comment Share on other sites More sharing options...
Jitters Posted July 30, 2008 Report Share Posted July 30, 2008 Where is all this about drilling it out and helicoiling it coming from? sure it works, but for me, that would be my NEXT to last resort for a simple snapped off bolt. The LAST resort would be the filing around the perch to get some pliers on the bolt. Wow... Guess I'm making too much of it.Steve's advice about proper drill bits is spot on too. Remember to drill slowly into metal also, adding oil for long jobs.So how did the bolt removal go? Any news yet?Now off to change that burned out lightbulb with a hammer... Quote Link to comment Share on other sites More sharing options...
StevenJJ Posted July 30, 2008 Report Share Posted July 30, 2008 Where is all this about drilling it out and helicoiling it coming from? sure it works, but for me, that would be my NEXT to last resort for a simple snapped off bolt. The LAST resort would be the filing around the perch to get some pliers on the bolt. Wow... Guess I'm making too much of it.Steve's advice about proper drill bits is spot on too. Remember to drill slowly into metal also, adding oil for long jobs.So how did the bolt removal go? Any news yet?Now off to change that burned out lightbulb with a hammer... Worked for me haha but i tend to bodge everything on my bike. :$ Quote Link to comment Share on other sites More sharing options...
Headley Posted July 30, 2008 Author Report Share Posted July 30, 2008 (edited) So how did the bolt removal go? Any news yet? Edited July 30, 2008 by Headley Quote Link to comment Share on other sites More sharing options...
Jitters Posted July 31, 2008 Report Share Posted July 31, 2008 (edited) It was nice and easy to get it out and the threads havn't been damaged so no helicoiling need Great to hear!I'm gonna try steve's trick of the torx head next time I run into this problem and I don't have any extractors handy. Sounds pretty good to me. Thanks! Edited July 31, 2008 by Tappets Quote Link to comment Share on other sites More sharing options...
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