What's your favorite "stuck bolt" removal process?

Snap-On makes a nice drill guide set; used it for years. Of course, you don't really need it. Grind the broken fastener flush. The center
drill point isn't the apparent center of the fastener, but the center of the major diameter of the threaded hole, apparent when you grind it properly. Center punch by eye; a light one. Move the punch mark as req to get it on center. For your 1/4" bolts, use 1/8"drill, drill just to the flute edge, and visually check the index. If no, angle the drill bit and adjust. When satisfied, drill all the way through the fastener, on axis. Usually, there is some open space under it. Squirt some penatrant in, and let it sit. I use the Snap-On straight flute extractor set; excellent quality. But note: extractors are intended to remove only fasteners broken off from vibration or over-torque. They are NOT for removing seized, thread-welded fasteners. Tap the 1/8" Snap-On extractor in about 1/4" . Apply only moderate torque. If the extractor starts to twist, pull it out with Vise Grips, and drill the fastener to the minor thread diameter. Chase the threads with a tap, and on to the next one. If you break off an extractor, delete last step.... JR Dweller in the cellar
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Thank you. I usually avoid easy outs, because the possibility of having to remove a broken one was such a negative thought. I see now when using one is appropriate.
Pete Stanaitis --------------------
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For getting a drill centered on a section of a bolt that's a bit higher than the surrounding metal, one could make up a set of drill bushings on a lathe, that would center a pilot drill. The bushings should get the drill started in the center, but won't help a lot with axial pitch. Not so simple when the bolt breaks off flush, though.
Managing a Dremel-type tool can be easier than trying to use a moderately large drill motor to get a center start on a broken fastener.
Having a magnetic base drill for steel/iron base material would definitely be helpful with keeping the drill on the axial center. Mag base drills are generally large and expensive, but the recent shop-built magnetic chucks made with high strength hard drive magnets shows that it may be possible to make a smaller version for pilot drilling broken fasteners.
Another tool that would help get a drill centered and keep the drill on the axial center would be a Cole drill. The foot/base that comes with the Cole allows for easy attachment to an adjacent fastener hole (head surface on a vehicle engine block, for example). Again, this example isn't very compact, but an inspired HSM could make some brackets to support a spindle and chuck, that would hold a drill perpendicular to a surface.
I remember seeing a drill motor with bubble vials on it a number of years ago, I don't remember the brand, or how long ago it was.
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WB
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Drill motors are made with bubbles, but bubbles are easily added with double-stick tape (and shims if needed) to other drill motors.
A carbide burr in a dremel-type (die grinder for the well equipped folks) tool is good for making a starting hole (and grinding out broken drills/extractors/taps, if need be - though it goes faster if you don't have to deal with those hard obstructions). Roto-zip tile cutters are a convenient hardware store source for carbide burrs, and they side-cut enough that you won't likely get that stuck if you manage to break it off in the hole.
The "candle wax trick" was lauded at anther place I frequent dealing with old machinery. I haven't tried it much yet. In thinking about it, it also offers the ability to do something about fasteners you may not plan to take out now, but which may not have been put in with anti-size - fill 'em up with wax now, and at least they won't be full of water and rusting (more) between now and when you get to them.
As for putting things back in, antiseize or loc-tite (depending on the fastener) will pay large dividends the next time you need to take it apart. Guy I sold my dead chevy to (for parts) was amazed when he took the springs (I'd replaced a decade or so earlier) off, since I had put them in with anti-sieze and silicone grease. Came right apart, no fuss.
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That is truly a problem, especially if the screw is broken off right at the surface. The threads make it awfully tough to tell where the true center is. And even if you locate it exactly, it's not easy to punch and start a drill there.
If the fastener is broken so that threads are showing above the hole or in it, things are easier.
I made up some screws drilled in the lathe right down their centers. If your screw is broken down in the hole, screw in one of your drilled scrrews as a guide for your drill. If the screw is broken above the surface, screw a long nut such as a coupling nut on it, then screw a drilled screw into the coupling nut.
John Martin
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When you are lucky, you can look at other features and determine a bolt pattern, spacing from another hole, measure the mating item, ect.
May designers that use dimensions like 1.37 burn in hell.
Wes -- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller
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A semi flat surface is key. Using a ball type carb burr will get down inside to take away the jagged broken off bolt end. After lightly punching, use a stubby center drill to start a point. Just like center punching, you can "walk" it around till it looks good. A lot of imagination is required as stated because the thread runs out on one side making the center visually look shifted.

Yep, but is it inch 3/8 or metric 10mm"? - 1/4" or 6mm? 5/16or 8mm? 1/2"or 12mm? Thats my biggest problem. Even comparing the pitch/dia. is a painstaking task since most bolts, when measured, are slightly under from their nominal. Some metric sizes have 3or4 pitchs! in each size, not even listed on most drill/tap charts. Dont even want to think about British Witworth - I feel sorry for you MG owners.

they are too lazy/forget to change their decimal place setting on the CAD? Unless configured, most CAD systems default are 2plc- like metric, or thinking 2place dec. will make it easier for the machinist - according to the 2plc tolerance print spec. IE: center punch & drill press?

Still gotta get that portable EDM attachment invented<g>
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<snip>

A friend of mine is a pilot for the airlines and he tells me "The aircraft mechanics have some stuff they call "Mouse milk" that they swear by, but despite requests from me they have never gave me any, so I don't know what it is." I DAGS and the first hit was http://www.mousemilk.com / Does anybody have any experience with this stuff? Art
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wrote:

It works.
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spaco wrote:

No one has mentioned my favorite for capscrews with twisted off heads. If the stub is at all proud of the surfcae, set a new grade 8 nut over it, start on the threads if any. Then MIG, TIG or braze the inside of that nut onto the stubb. Presumably you have applied penetrant before reaching this point. Let it cool (or wait a bit then hit it with some ice or refrigerant spray). Remove with hand tools on the nut.
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spaco wrote:

Good. If its actually a problem of the bolt head getting rounded off by a bad socket or wrench, they work great.
If the bolt is seized and the head got rounded off fighting with it, these extractor sockets will just allow you to get a good grip on the bolt head so you can snap it off. Methods for freeing the stuck threads must still be employed to prevent this.
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Paul Hovnanian snipped-for-privacy@hovnanian.com
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