OK lets say you've screwed up and busted off a EASY-OUT hardened steel bit during the bolt removal process, now what?
obviously you'll quickly find out that standard drill bits won,t touch a l EASY-OUT hardened steel bit style bit as its far harder than most standard drill bits
you should know that hardened steel requires a slow drill speed (UNDER 300rpm in most cases) AND REQUIREs a constant flow of cooling oil, or a hardened drill bit will very quickly loose its edge, in seconds in some cases, YES IM WELL AWARE,that the tendency is to lean on the drill bit and spin it as fast as you can, which is exactly the wrong approach here, you need to apply steady pressure and low drill speeds and frequent lubrication, Ive used marvel mystery oil mixed with about 30% acetone as a lubricant for years with good results, but its very important to lube frequently,and drill slowly WD40 works as does CRC spray lube.
a hardened center punch helps center the bit and keep it from wandering off center.
http://www.ehow.com/video_4950955_drill ... steel.htmlhttp://www.youtube.com/watch?v=D4q8UhbpaG0When to Use a Carbide Drill Bit
By: Gene Rodriguez, III
Drill bits undergo a lot of stress when drilling a hole. The high-speed rotation of drill bits generates friction that, in turn, generates heat. The friction between drill bit and material leaves drill bits slightly duller after each use. The heating and cooling of the drill bit material can weaken the internal structure of the bit over time.
The Common Drill Bit
Common home repair drill bits are made of steel or High Speed Steel (HSS). Although inexpensive, common steel drill bits tend to wear out or break very quickly. HSS drill bits last longer than steel, but are more expensive. These types of drill bits are most effective when used on wood, drywall or plastics.
A Bit Stronger
Coated drill bits use another, harder material to coat steel or HSS drill bits. Titanium carbide or titanium nitride coatings can increase the lifespan of a drill bit by two to three times. These types of drill bits are useful when drilling hardwoods or thin metals.
When The Going Gets Tough
Carbide drill bits are among the strongest drill bits available for home use. Carbide drill bits are more expensive than steel or titanium coated drill bits, but will last longer and stay sharper.
Carbide drill bits are absolutely necessary when drilling stainless steel or other high-density materials. No other drill bit can handle the job.
Regardless of the material that you usually drill, a carbide drill bit will last up to 25 times longer than a common steel bit. This can make carbide drill bits an economical choice for woodworking, furniture building or other large-scale projects.
When cutting dense material, use a cutting lubricant to avoid generating excessive heat. Overheating a carbide drill bit will shorten its lifespan. Always let the drill bit do the work. Applying too much pressure will quickly dull your drill bit.
http://www.ncprogramming.com/drill_size_chart.htmlhttp://www.thetoolhut.com/tap-drill-sizes.htmlhttp://www.drillbitwarehouse.com/home?p ... egory_id=9titanium drill bits, better than high speed steel but may not be hard enough
Carbide drill bits,very good but fairly expensive
diamond drill bits--best, very expensive
