Drill Bits or Maybe Advice

[bnau267]

Attach your link to the drill bits I should be using for drilling out bolts, through sheet metal, etc, etc. Explain when to use cutting oil if ever when drilling.

[Hawaiiysr]

Cobalt bits. Steady hard pressure. Not to fast or you'll burn the tip. Use oil to keep the tip cool. I'm sure others will have more to say.

http://home.howstuffworks.com/cobalt-drill-bits.htm

[rk88r]

You know it's going well when the material curls out into spirals.

[bnau267]

You know it's going well when the material curls out into spirals.

I will take that into account.  No big curls means something is going wrong....lol.

[Hawaiiysr]

If you can hit the broken bolt with a pointed punch. It will help the bit bite. Last thing you want it the bit to wonder. If the bit wonders then your hole will be off center or crooked. Chips are good to but a nice curly shavings are best.

[Pumashine]

No big curls means something is going wrong....lol.

They don't have to be big. If the bit is taller on one side then only one side may be cutting. Happens if you do not resharpen the bit evenly. Then you get lots of little chips coming out instead of one spiral curl on each side. Always use cutting fluid on steel and stainless. On aluminum wd-40 works fine or an oil and kerosine mix for tapping aluminum.

[bnau267]

Do you guys buy bits from Grainger, etc or Home Depot?

[Pumashine]

If you can hit the broken bolt with a pointed punch. It will help the bit bite. Last thing you want it the bit to wonder. If the bit wonders then your hole will be off center or crooked. Chips are good to but a nice curly shavings are best.

In the shop there is a item called a center drill. It is a stout drill with a small tip. Center punch where the hole you want. The center drill does not wonder like a regular bit because it has a very small tip but does not flex like a 1/8" drill bit. You only start the hole with a center drill and go 1/4" deep. I grew up with the craftsman drill bit set cause my dad only went to Sears for anything.

[C-Leigh Racing]

Theres a reverse set type of bits that are good to use & sometimes just the drilling process, will back what is left of the bolt out.
Once you get the broken bolt out, just remember real good all you had to go through to get it out & put some anti-seize on the new bolt or stud. Not every bolt or stud needs locktite, cause long as the threads in the hole & those on the bolt or stud are clean it will hold.
Neil

[Hawaiiysr]

I get my bits from both Grainger or home depot. Just depends. Company account ya know...

[bnau267]

Alright I'm gonna study and practice and study.  I fry bits like no other.

[C-Leigh Racing]

Good sharp bit & real low speed, will last you awhile. With slow rotation speed, you could take an old cheap Globe master drill bit & get the job done.
Neil

[Rupp250]

For broken bolts, left hand drill bits.

http://www.northerntool.com/shop/tools/product_34761_34761

[havinnoj]

When drilling bolts out, it's always good to have a rethreading/thread restorer kit around.  These are made to help existing threads and not remove as much material as a true tap and die set (although they function the same).  The Kastar 971 set (now renamed Lang Tools 971 and made in the USA) is the OEM for Snap-On (Snap-On RTD48) and Matco (Matco TDK51).

[ytman]

I just watched a video on you tube about Artu drill bits that goes against everything I have ever been taught about drilling steel.