Removing a broke off thread

[Frank S]

A mechanic friend of mine dropped off a part that had the Dutchman thread of a horizontal boring bit broke off deep in the part
Asked me if I could get it out for him because he knew how tight those things get.
So I torched a couple holes in one end of my work table bolted and clamped the part down then proceeded to weld down inside until I had the weld built up high enough to weld a 1" nut to it. Once it had cooled I put a 1 /12" box end wrench on the nut and whacked the side of the wrench a couple times with a 10 lb sledge hammer, the Dutchman screwed right out.

[WmRMeyers]

Nice combination of Blue Wrench and Percussive Maintenance!

Bill

[Frank S]

Nice combination of Blue Wrench and Percussive Maintenance!

Bill

Yes, in this case the blue wrench was in the form of duel shield flux cored wire. When something is broken off as deep as that one was, on top of being a tapered thread hydraulically torqued, welding them out is usually the fastest option. Not only does the welding allow you to build up to surface so you can attach a means of twisting it, but the heat from the welding causes expansion and the gradual cooling contraction. You never want to quench or rapid cool because it will make things brittle . The filler wire I use has nearly 90,000 lb tensile strength, but for times when that is not enough I have some stick electrodes that have a 250,000 PSI yield

[DIYer]

Thanks Frank S! We've added your Broken Thread Removal Method to our Metalworking category,
as well as to your builder page: Frank S's Homemade Tools. Your receipt:

Broken Thread Removal Method by Frank S

tags: extractor

[mwmkravchenko]

Nice one Frank. Must have been glowing red hot by the time you were up high enough to weld on the nut!