Getting snapped off bolt out of hole

[andrewj]

Hi folks - I bought a used Kubota, the last owner somehow snapped off a bolt shaft inside the area where the ROPS is mounted. It now has 5 bolts instead of 6 holding it on. I feel it is secure, but I want it fixed.

How do I get the threaded shaft out of the hole without boring it larger? Thanks.

 

[carpenter383]

You can try an easy out, you drill a hole in the center of the bolt, then use the tapered drill bit looking thing which has left handed threads to back it out. Or you can try this...drill a hole in a peice of flat steel a little smaller than the broken bolt hold the hole over the broken bolt and weld the flat peice to the broken bolt through the hole. If possible make the flat piece of steel long enough to leave a handle for turning the bolt. The heat from the weld will help break the bolt loose. I have heated rusty bolts up with atorch, then quicly pour cold water on them too, this helps break up the rust.

 

[Willl]

If I have to drill it, I use a LH drill bit and sometimes don't even need the easy-out.

 

[gc2310]

Do yourself a big favour and don't use a tapered easyout. If you are going to try that method, use splined extractors made by Rigid [ also available from Snap-On]. Best way is to drill out to tap size and then run a reverse spiral tap in to pick out what's left. NOTE; you have to drill dead centre. Good luck.

 

[2manyrocks]

Look at the remaining bolts to see what hardness grade you are dealing with. My guess is that this is a pretty hard bolt.

If you want to try the welding method suggested, you may want to apply a good quality penetrating oil to the bolt after you've made a solid weld.

 

[Sherweld]

You can try an easy out, you drill a hole in the center of the bolt, then use the tapered drill bit looking thing which has left handed threads to back it out. Or you can try this...drill a hole in a peice of flat steel a little smaller than the broken bolt hold the hole over the broken bolt and weld the flat peice to the broken bolt through the hole. If possible make the flat piece of steel long enough to leave a handle for turning the bolt. The heat from the weld will help break the bolt loose. I have heated rusty bolts up with atorch, then quicly pour cold water on them too, this helps break up the rust.

The above solution works very well for me, although instead of a flat with a hole, I weld the largest nut whose hole is smaller than the broken part. This allows a choice of wrenches, plus the heat of welding usually does a pretty good job of loosening the broken part.

Sherweld

 

[JoeL4330]

if there is the least bit of bolt exposed, before I tried anything else, I would use a small cold chisel and hit it counter-clockwiseat the periphery ...penetrating oil/liquid wrench, etc. too ...The chisel blade has to be quite small (bolt radius or smaller) and or tilted slightly to only engage a corner of the chisel. Lots of little, persistent taps.

 

[zzvyb6]

Try removing a few of the other bolts in the mount to see how snug they are. If they are loose, then the chisel or star bit will work fastest(best). If snug, the a small drill and an easy out is best (cheapest). The end of a file or concrete nail works too, depending what you have laying around the garage. The problem you will have is that the boken stub will not lend itself to a centered pilot and a regular drill will try to move it inward. However, some of the stuff being posted that you need to buy will NEVER be needed again, so keep your purchase tactics in mind for this. Another method I've used is to stuff a live welding rod in there and have it fuse to the bolt. The heat and the steel is enough to back it out. Oh yeah, there will be some sputter in there, but its faster that fixturing your tractor up in a mill, lathe or drill press, boring out the bolt .0001" undersize and chasing the threads with a 17mm metric tap. As I read it, this is a cosmetic issue more than a safety issue. If this was a cylinder head bolt, maybe a more serious problem. The probability of you actually laying the tractor over on its roof times the side you choose to roll with, divided by the remaining bolt attachment strength is a pretty small number.

 

[Travelover]

If I have to drill it, I use a LH drill bit and sometimes don't even need the easy-out.

I'd second the left hand drill. Harbor Freight has a set that is pretty inexpensive. As noted, often the heat and vibration of drilling makes the bolt come out by itself.

 

[JoeL4330]

Try removing a few of the other bolts in the mount to see how snug they are. If they are loose, then the chisel or star bit will work fastest(best). .

never thought about star drill ...mounted in drill, in reverse?

those who advocate drill bit (reverse or otherwise) are certainly better machinists than I, unless it is somthing I can bring to the drill press or mill ...a portable drill has never worked for me on a hard bolt ... now, maybe if I had a magnetic drill, hmmmm