Replies

1. 
   Sphere | Jul 21, 2007 01:22am | #1

   Uni bit is perfect for that.

   Just stay away from Harbor Freight brand, Irwin is good, Greenlee better but more $$$$.

    

2. 
   JTC1 | Jul 21, 2007 01:25am | #2

   Ditto to Sphere. Good excuse for you to buy a new tool!

   Jim

   Never underestimate the value of a sharp pencil or good light.

3. 
   DanH | Jul 21, 2007 02:00am | #3

   I've actually done this with a good quality "repairman's reamer". A little tough on steel, but works real well on aluminum.

   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
1. 
   Yersmay | Jul 21, 2007 02:40am | #4

   Thank you for your responses!

1. 
   brownbagg | Jul 21, 2007 02:51am | #5

   you need one of those step drill bits. they alway used them on american chopper. I have one but they are not cheap

4. 
   WayneL5 | Jul 21, 2007 05:24am | #6

   You can use twist bits if you can use a drill press and clamp the work down.  Otherwise the Unibit is the way to do.  A cheap one will probably suffice for the few holes you need.

   They are common among electricians, so an electrical supply house will have them.

5. 
   JasonD | Jul 22, 2007 05:04pm | #7

   I'd 2nd (or 3rd) the use of the step drill. I never use a twist drill bit in thin metal anymore.

   -- and spin it SLOW - maybe use the geared down speed of a cordless drill.

   A drill press would work the best, just because you can get a better, straighter pressure on the step bit.

6. 
   Dunc1 | Jul 31, 2007 06:01pm | #8

   I agree with the cone drill.

   Twist drill bits can be used if they have the correct tip grind. I bought some years ago but when I want them to refresh my memory they are nowhere to be found. If you want to go this route Have a look at specialty drill bit suppliers, for eg:
   http://www.milwaukeeconnect.com/webapp/wcs/stores/servlet/product_27_40028_-1_683840_192622_192327

1. 
   DanH | Jul 31, 2007 06:08pm | #9

   I believe that you can occasionally find twist drills with a triple spiral. These (I've heard) are more stable when drilling thin materials.
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

1. 
   TJK | Jul 31, 2007 06:26pm | #10

   It doesn't matter how many flutes they have, spiral bits are never good in thin metal. Previous posters are right - use the step drill. As a general rule of thumb (especially if you want to keep both of yours) never use a twist drill bit larger in diameter than your little finger unless the work piece is clamped and on a drill press.

1. 
   DanH | Jul 31, 2007 06:33pm | #11

   With more flutes there is less "chatter". There is still the tendency to "suck" the workpiece, of course, but that's controllable by controlling feed rate.
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

1. 
   TJK | Jul 31, 2007 06:46pm | #12

   Chatter isn't the issue. Fluted drills do not make round holes. Since the hole is not round, the bit catches on the "corners" as it revolves. With a 1/8" bit that's not a problem. But take a 3/4" bit attached to a 1 HP motor and suddenly the torque transmitted back to the guy trying to hold it steady is more that most people can handle.

2. 
   DanH | Jul 31, 2007 07:02pm | #13

   The drills don't make round holes because they chatter.
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

7. 
   rwjiudice | Jul 31, 2007 07:18pm | #14

   My projects include drilling lots of holes in metal. After ruining several metal units using a twist drill in a drill press, I purchase a step bit (uni-bit) and havn't looked back yet.

   Ever watch OCC (Orange County Choppers) ??? They use nuthin BUT UniBits. That was my clue.

1. 
   sapwood | Jul 31, 2007 08:42pm | #15

   The Unibit is good but I've enlarged many holes in 1/8 steel from 3/8 to 1/2". Go slow, use slight feed pressure, and use a large drill motor with plenty of torque.