Ultra Palm Optical's Cazal style 1151

PROBLEM: Regular grooves don't work in new designs
SOLUTION: Some new frames require larger grooves. A thicker groove-really a reverse bevel-is needed in order to fit the lens into the frame. You need a groove that's about double the width of a regular one.

With some edgers, you can choose a wider width for the groove and cut it automatically. But with a hand groover, it can be difficult to get that wide width.

-Clark Smith, Santinelli International

PROBLEM: Semi-rimless lenses chip 
SOLUTION: If the groove is placed too far to the front of the lens, you run the risk of chipping the lens when you mount it. Aside from making sure that the groove is placed closer to the center, be sure to safety bevel the edges immediately to protect them from chipping. You want to put a safety bevel inside the groove itself also, especially with the new, larger grooves that are being used. You can use a square ceramic stone with a 90-degree edge to bevel inside the groove, or use a ceramic block to do it manually.

-Matt Vulich, AIT Industries

PROBLEM: High minus lenses don't lend themselves to semi-rimless frames 
SOLUTION: On most edging equipment, rimless jobs are the simplest to do. Normally, with a frame that requires a regular bevel, you have to be concerned with the bevel placement. With rimless, it's just a flat cut, then you can polish the edges, either on the edger or by hand.

But with heavy minus lenses, such as a -8 or -10, a straight bevel won't look nice. You should roll the edges to give them a thinner appearance, and polish them clear as well.

-Bill Galindo, ODI/Topcon

PROBLEM: Screw holes are too large
SOLUTION: In order to find the correct location for drilling or notching a lens, you need to lay out the lens correctly. Once you've done that, drill the holes at a right angle (straight on).

Also, drill from both sides. Mark the locations for the holes on the front and back of the lens, and drill through to the middle. Drilling from both sides reduces chipping and also helps to get a better fit with less stress on the hole.

-Michael Urban, Gerber Coburn

PROBLEM: Screw holes are too large
SOLUTION: In order to find the correct location for drilling or notching a lens, you need to lay out the lens correctly. Once you've done that, drill the holes at a right angle (straight on).

Also, drill from both sides. Mark the locations for the holes on the front and back of the lens, and drill through to the middle. Drilling from both sides reduces chipping and also helps to get a better fit with less stress on the hole.

-Michael Urban, Gerber Coburn

PROBLEM: Holes are drilled in the wrong place on the lens
SOLUTION: If you have an edger that can automatically drill holes for mounted frames, it simplifies getting them placed correctly. You choose where the holes belong during the blocking process by moving a cursor to the right spot on an image of the lens. You just put an "X" on top of where the holes are in the demo or glazed lens, and the edger drills them automatically. It's much easier to get the holes in the right place beforehand than having to figure it out and do the drilling by hand afterwards.

-Jeff Wallish, WECO

PROBLEM: Rookie lab techs have trouble faceting
SOLUTION: Facets are done by hand on a handstone or on a facet machine with a flat round plate that spins while the lens is held in place in a second operation following edging. Some edgers have an optional, special-order cutter that puts the facet on the lens during the edging process. But even using this method, the facet must be polished out afterwards.

When polishing, there is an opportunity to scuff the front or back surface of the lens. It takes practice and good technique as well as a light hand to be able to polish facets well by hand.

The alternative to hand polishing is to use a liquid edge polish, which is like a clear fingernail polish. It works on CR 39, high-index and poly, but in some cases it deteriorates over time. You have to decide whether it's worth it to take the shortcut and use the polish.

-Stuart Watson, National Optronics EB

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