Using A Step-bit Drill

Have any of you used a step-bit drill to make a relatively large hole in a jeep body? I ask because I want to put in a cut-off switch in the fender well on my '66 CJ-5 F4, locating it approximately where the battery is inside the hood. There is already a hole in the fender well about 1/4" diameter that was likely ''stock", as I don't remember ever drilling it, and I want to enlarge it to about 5/8" to get one end of the cut-off switch thru the hole and lock it in place with the nut that came with the switch. Some Googling revealed that a step-bit drill may be the answer for enlarging holes (it's cone shaped, continually providing a larger and larger hole during drilling), and it is relatively low in cost.

Is this the tool to use to create a 5/8" hole in the jeep tub? If so, any pointers to offer?..... or maybe an alternative method? -- thanks

 

Use a Sharpie to highlight the step you want to stop at. Like Howard says, you don't want to over-run the step.

Step-drills are specifically designed for sheet metal. The only better way is with a chassis punch, and each punch only makes one size hole.

 

Excellent , everyone! I appreciate all your comments and suggestions. I'll buy a step-bit this weekend and get to work.

 

I only use regular drill bits to start a hole these days... Step bits rock

 

I've had pretty good success using a small step bit for drilling out spot welds.

 

My advice for making sure you get the right hole size is to wrap masking tape around the step above what you need... just drill up to the tape.

 

These Rotobroach cutters really work well in sheet metal and even up to 3/8" plate...........not distortion at all on sheet metal.

Rotabroach Cutter Kit - Metric

 

Agree, these make nice holes, but boy has the price gone up. $54 for one small die. I think my old set that goes up to 6-1/4" with the hydraulic ram was only about $150 when I bought it a long long time ago.

 

X2 on the Blair cutters for spotwelds. They are the only thing I have found that cuts only one side of the spotweld, leaving the second layer with only a nub to grind off. I didn't know they had metric sets, and my SAE set was less than $40 a few years back. These, and step drills can accomplish the same job, but each has its own application.
-Donny

 

Do use tape as a stopper to NOT oversize the hole