Snapped Bolt ?

[bobm]

A 5/16 bolt has snapped off flush with motor. I would like to remove without damaging female threads,but I do not have a tap/die set. So I drilled a 1/8 hole through center. Is there a reverse thread self tapping bolt I could get or shold I try increasing drill bit sizes in order to get it out.

 

[Backlash]

Re: Snapped Bolt ?

Hey Bob,<br />You'll definately need to increase the size of the hole in the bolt before you try anything to get it out. If you think you've got problems now, just break off an easy out in that puppy. You must be absolutely sure you've got that first hole drilled dead center on the bolt. You can increase the drill sizes then re-tap. You'll need to buy a tap (don't need the whole set). Good luck. It can be pretty tricky. <br />Backlash

 

[icytek]

Re: Snapped Bolt ?

If you drilled the bolt already with a 1/8 you do need to go up in size of the bit. The easy way would be to go to a hardware storeand look for an extractor. The extractor will have which size drill bit to use to get the bolt out. Just make sure that the bolt is drilled dead center so that you have a lot less chance of twisting the extractor to the point of it breaking off in the bolt.

 

[norman158]

Re: Snapped Bolt ?

soak that broken bolt real good with a good penatrating oil not just w d 40 before you try to remove it

 

[kenthrussell]

Re: Snapped Bolt ?

the best idea would be to use a tap drill for 5/16 and retap providing you drilled the bolt dead center...

 

[Jomusky]

Re: Snapped Bolt ?

I always drill the easy out holes with left handed drill bits. Starting with 1/8" and stepping my way up. Many times the drill will catch and back the bolt right out. Drilling in the center of the bolt is very important and will take some practice to get good at it. An important tip is to make sure the broken face of the bolt is flat by grinding with small pencil girinder so the drill doesn't wander. Then if that doesn't work I try an easy out. Last resort is to drill and tap since this usually wrecks some of the existing threads.

 

[Jomusky]

Re: Snapped Bolt ?

One more thing is the best penetrating oil is called PB Blaster. It blows away all others.

 

[bobm]

Re: Snapped Bolt ?

Lesson learned the hard way ! Drilled out to 1/4" then tried an extrator,but I snapped it off flush ! GREAT spent next 2hrs using small cutoff wheel to grind out extrator, with slow sucess was able to remove rest of extrator tip.Then I drilled up to 7/64 for retapping,once there old threads fell out while tapping.<br />"I WILL STAY AWAY FROM EXTRACTORS IN FUTURE ATTEMPS ON THIS MOTOR"<br />THANKS FOR THE ADVISE!