With the exception of two people, all of our lab techs have come from other labs. We are experiencing a difference in training techniques. Some techs say that only the back side of a lens should be beveled. Some say that front and back should be beveled to help prevent chipping. Some say that beveling has no effect at all on chipping.
Another difference of opinion is whether to completely unscrew the eyewire to mount the lens, or loosen to where it is barely engaged.
Any comments?
On glass and all rimless I safety both front and back of the lens and the rest just the back side.
I know there are plenty of different training techniques in the optical world, as for taking a screw completely out or just opening the barrel, I'd say use whatever is most successfull for you.
Rich R
I could not find any specific reference in ANSI regarding 'safety bevels'.
However, most places I see do NOT safety the front of beveled non-glass lenses. They safety both side on all glass, and both sides on any groove/rimless lenses - any material.
I believe the intent of the safety bevel was to remove chips/spurs and sharp edges from glass lenses after edging - to smooth the edge. Plastic lenses do not normally have a sharp edge on the front.
Darryl may have other information. If I recall, he is on the ANSI board.
Among other things, the safety bevel is put on the back for.....safety. The back edge is sharp and left untouched could be a cutting hazard to a persons face if their glasses get bumped hard enough. I have seen it happen(not with my product thank goodness) but with my competitions. So, be sure to safety bevel the back!
My few years in the business (30+) and my lack of "formal" education have lead me down the path to train new opticians to bevel / chamfer both edges. It annoys me to feel the sharp front edge on any organic (plastic) lenses - it feels quite unfinished. While we did put safety bevels on glass lenses it had as much to do with technology at that point as it did with safety - the finishing wheels left "stared" and chipped edges that needed to be smoothed out. However safety is a critical issue.
BTW I have a habit of putting on two or three angles (very lightly) and the higher the minus the more so. I also take off the hide-a-bevel(put on a standard "V" bevel) in the nasal area and the pad arm area for safety and adjustment purposes.
Glad someone brought this up - it is an important feature to a well finished pair of lenses - details, details, details
Don't do any inhouse glass anymore, but when I did, obviously safety beveled both front and back.
Rimless, I also do front and back.
As far as other types, I don't go heavy on the front, but do touch it off. I believe it makes a more finished product. I also believe that on any finished lens with AR coating, a light touch helps to resist any coating problem on the edge.
Just my two cents worth.
Diane
Yes, front side is a hold over from when we did glass. With the advent of new generation edgers, you should not have to safety bevel the front side anymore.
I always safety bevel the "back" side, and "never safety bevel the "front" side, except on glass, and we have that done out.
Hey Al, ya'll would need to change your ways to work in may office !!! That's OK, I'm kinda hard to work with anyway so you'll probably stay in Texas.
BTW are you planning on Anaheim?
Richard
For the most part I practice the same technique as Homer. Back bevel at three angles, kind of a miniature roll, but it is a pin bevel. I use a little heavier hand for higher minuses. Very light bevel on the front. In the case of plus lenses I use a very light hand; too heavy and it makes the lens look boxed off and bad. I bevel rimless jobs front, back and center. Those three angles, again, give you that miniature roll effect, smooth at any angle. Like Homer said "details," kind of like a dove tail joint holding together a drawer. You don't see the joint when the drawer is closed but it makes a big difference in the quality and durability of a piece of furniture. (Sorry, I have watched American Masters on Home and Garden Television a little too much.) ;)
I am with Jo and Homer. It takes less than one minute on a hand edger to properly finish the lens on the front and back surface. After 20 years in my shop, I can always identify a lens that walks in my door (on a person's face, of course) that we did not finish. I will always make mention to someone that theirs was not finished as it could have been and show them the difference.
Detail, detail, detail.
Jackie O
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Still a Maina for now
I bevel front and back on rimless and very high rx when you can really feel the sharp edge. I also use a very light touch on the front bevel. Other than that I usually just bevel the back side.
Have a great day!!
Steph
Thanks to all for answering my question. I feel better about beveling both sides now. We send lenses to our other stores, and they do their own tinting. I feel that a light bevel on the front helps to keep them from chipping the lenses.
I pin (safety) bevel front, back and the apex of the bevel.
Original theory was that force and stress vectors go in a straight line. Lenses under compression (IE a frame) are more apt to chip/crack/split etc. with no pin bevel, Pin bevel redirects the stress force internally (around the curve of the bevel).
It also allows lens to pop into frame without opening barrels completely and without changing the size of the lens.
Theory two is: blunt edges don't cut!
Duh!!!
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