Extracting Broken Bolts, Studs, Extractors, Drill bits, and Taps
 

Extracting Broken Bolts and Studs
http://www.dimebank.com/tech/BrokenBolt.html

The Art of Extraction
http://www.asashop.org/autoinc/may2003/techtotech.htm

Extracting A Broken Bolt Or Screw
http://www.amazines.com/Construction/article_detail.cfm/307403?articleid=307403

Removing broken bolts with stick welder
http://weldingweb.com/archive/index.php/t-7834.html

Here's a guide to un-sticking stuck fasteners.
http://www.motorcycle.com/how-to/how-to-extract-stuck-screws-3440.html

remove broken tap drill or stud
http://brokentap.blogspot.com/


Note:
In some areas there are specialty shops that do this for you.
Example:
http://www.brokentap.com/services.html

Good data
 

Knowing how to remove broken fasteners, extractors and/or drills, before it happens, can make this a none issue.

Loosening rusted bolts and nuts
 

In an email from my brother:
You guys may be interested in some interesting information that I found in the Studebaker Drivers Club rag. They gleaned it from another magazine, the Machinist's Workshop rag. It has to do with loosening of rusted bolts, and penetrants contribution to that effort. It was from an experiment repeated many times, them averaging the results for each penetrant. Every effort was made to ensure evenness in the rusting.
Penetrant Average Torque
None 516 lbs
WD40 238 lbs
PB Blaster 214 lbs
Liquid Wrench 127 lbs
Kano Kroil 106 lbs
ATF-Acetone mix 53 lbs

It would appear that WD40 and PB Blaster aren't nearly as effective as liquid wrench or Kano Kroil, but the home-brew mix of ATF and Acetone is a real winner.

from the source
 

Machinist's Workshop magazine actually tested penetrants for break out torque on rusted nuts.
Significant results! They are below, as forwarded by an ex-student and professional machinist, Bud Baker.
*Don't forget the April 2007 "Machinist's Workshop" magazine comparison test.*
**
*They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment. *
**

*Penetrating oil ..... Average load*

None ...................... 516 pounds
WD-40 ................... 238 pounds
PB Blaster .............. 214 pounds
Liquid Wrench ........ 127 pounds
Kano Kroil .............. 106 pounds
ATF-Acetone mix.......53 pounds

*The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone.*
*Note the "home brew" was better than any commercial product in this one particular test.
Our local machinist group mixed up a batch and we all now use it with equally good results.
Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price. *
**
*Your experience may vary, etc., etc.*

Can't wait for them to check Deep Creep.

I'll agree with the acetone, ATF (and old brake fluid) too
I knocked apart (removed pistons) an engine with this.

Left-Hand Drill Bit Set
 

Bump
 

for customer