Drilling Polycarbonate

[Pete Hanlin]

While reading my latest issue of Lenses & Technology, I noticed a comment about drilling polycarbonate...

<FONT COLOR=#FF0000>"Polycarbonate cuts best with a sharp burr operated at low speeds of 20 to 60 revolutions per second and minimal to moderate pressure. Twist style drills, cutting less agressively, often leave subsurface damage."</FONT>

Can anyone elaborate on this? For example, where can I find a burr that is a specific diameter (say, 1.4mm, for Titan jobs)? Also, can a burr even be used with metal drilling guides (like those used for Marchon's rimless Autoflex and Silhouette's Titans)?

Thanks,
Pete

[Darris Chambless]

Howdy Pete,

You can get the same effect with a variable speed Dremel and your regular drill bit. I use a variable speed drill press for most of my poly. The slower the bit turns the cooler it stays and will bore through the material much better with less damage to the bit as well as the lens. The same holds true with mid and high index materials, but the bit must be good and sharp ;-)

I have used burrs before and don't like them as well for drilling. Burrs tend to pop out what I call a plastic divit at the end of the drilling process and it is always larger than the hole being drilled. I use them for etching and other art work on the lenses and frames. As to where to get them ask your dentist to save the old ones for you. That's what I do. Or you can go to Wal Mart or any other store that will carry Dremel accesories and get the burrs for this system.

Hope this helps.

Darris C.

[chip anderson]

If you have a local dental supply they will have burrs of every imaginable diameter. If you can't find a local go on the webb. If all that fails E. Mail me, I will send you some addresses. Also note: You really need burrs held or mounted firmly, it's real easy to go al the way across the lens leaving little track marks. Also if you have a dentist friend, he can probably help and will have suppliers and catalogues.

Chip