Hi,

I just purchased some strobe lights for my truck and was wondering what kind of drill bit was needed to drill out the lens of the foglight without it cracking on me? The hole needs to be 1" diameter.

Thanks for any help and will post video when finished.

 

Start small and work your way up, if you are working on a uneven surface i recomend using a scroll or sharp object and just "push" into the plastic giving you a location so your drill bit doesnt wander around.

 

why not use a 1" hole saw.

 

...you can try to run the bit in reverse also. It keeps the bit from grabbing and cracking the plastic. You'll need a fresh hole saw or bit.

 

High speed / Low pressure, when using a drill bit, dull the drill bit by putting it in concrete and spinning the drill. yes that wipes the drill bit but thats how its done for aircraft. Or use a unibit

 

Uh..for just drilling through plastic. Sharp bit is best.

 

For drilling through brittle plastic, use a drill bit designed for glass and tile. I used to use these every week when I installed powder coating systems and they were the only ones that wouldn't occasionally crack or fracture the plastic. Don't know if they come in 1" or not. Good luck.

 

(The drill used on acrylics must be carefully ground and free from nicks and burrs that would affect the surface finish. Grind the drill with a greater included angle than used for soft metal. The rake angle should be zero in order to scrape, not cut.) Drills for plastics should have an included angle of approxiately 90 degrees, lip relief angle 12 -15 degrees and a chisel angle between 125-135. Dept of Transportaion, Aircraft Repair & Alterations AC 43.13

So basically that means stick the thing in the cement and dull it. A sharp drill bit will grab the plastic like a screw and blow the back side out leaving it to crack and splinter.

 

Thanks to all for your help. Tomorrow I will go buy some bits and try to do this.

 

I reccomend a stepped bit like those put out by "Green". It cuts everything like butter.