I've broken a stainless steel bolt (0.31" Dia) almost flush in an aluminum housing. There is nothing to bite on and the bolt had red locktite on it from the previous owner or his mechanic.

ANy suggestions on removing the bolt without damaging the threads on the aluminum housing?

 

You need to center punch the bolt, drill it out for an easyout and use a low speed drill with lube, then a good soldering iron or a pencil torch for a heat source to soften the loctite BEFORE you try and take it out. Heat's about the only way with the red stuff in your situation.

 

Sounds like a 5/16" bolt, should be enough meat there to carefully drill and take out with an easy out. Stainless is relatively soft, should drill easy. If the broken end is too irregular and the drill bit wants to wander, try to grind or file a flat on the end and dimple the center with a pointed center punch to get the bit started. Here's a chart for sizes:

http://www.engineersedge.com/manufac...rill_13412.htm

I can almost guarantee it won't come out with an easy out if red loctite is in there without heating it first. Here's info about that:

http://us.henkel-adhesives-blog.com/...-Threadlocker/

I think a heat gun works better for this than a torch, less chance of damaging surrounding stuff. Probably the cheapest you'll find are on ebay or Harbor Freight, but I don't know if they'd last long. I probably put over 100 hours on a Sears heat gun that cost around $100, but I suspect a $15 or the better? $30 ones at HF would be good enough for removing a few bolts. When you have one, they come in handy for other things, too.

If you have to buy some tools, it might sound expensive for one broken bolt, but the right tools are for saving the expensive housing, not the bolt.

 

Hi Twizted, got in here while I was typing. Pencil torch sounds good, too, didn't think of that. Probably not thinking of a lot of things this late... Bet I easy outed over a 1000 busted or stripped head screws and bolts on airliners, only a few on motorcycles. Hated the ones under 1/4", not much there to work with.

 

or 8mm ...only ~.0025 diff

Not that any of that matters other than for drill selection and possible forthcoming thread insert selection

 

left hand drill bit

 

Not with red loctite, you'll just make the hole bigger and harder to use an easy out, would probably break the drill bit before the loctite lets go. Friction won't get the 500+ degree heat necessary to loosen the loctite, either. That's a good method when there's no loctite.

Worse case scenario, have to drill it all out, tap for a larger size or use a heli-coil; I've done both. Tapping a size up isn't an option in some situations. What can be a problem with either is metal shavings getting into the other side of the housing.

 

Drill the broken bolt (stainless is soft but use a cobalt bit), heat the area to liquefy the red loctite (heat gun or pencil torch) , use a high quality EZ-Out. Nothing else is likely to work.

 

"friction" ?

Why do you think a LH drill changes anything compared to using a RH?

You would still use the same process steps (particularly heating). LH drill bits can effectively become the "extractor", but while you may have to still resort to an "easy-out", no harm...no foul If one is available




EDIT: I just got it...You think he means running a RH drill bit BACKWARDS (in reverse)
.
.
.

 

"Sharpie" Screw Extractors are a great tool. There are different types. I've found that one made by Snap-On ( Rigid ) is a bit better and more forgiving ( it isn't as brittle so is less susceptible to breaking during use ). It's a "splined" type. http://www.testequipmentdepot.com/pr...FZaEaQodwdsOtQ

As mentioned earlier care and patience are valuable assets when drilling. A precisely placed center punch will keep you on the straight and narrow too. Always start with a small bit ( easier to control and require less pressure ... less pressure will keep the bit walking or going off course ) and work your way up to the size needed. Once you're ready to use the spline, drive it in AND THEN remove it. Now is the time to heat the broken bolt to break the bond. If you heat the broken bolt before doing so it can/will make it brittle and hard. Then re-insert the extractor and remove the bolt. In the event that you do need to do a thread repair ( oversize ) I would recommend a Time-Sert. They are much easier to use than a Heli-Coil for the novice. http://www.timesert.com/