Ok fellow opticians,
When should I use a 1/3 to 2/3 bevel versus at 50/50 or a layover.
For the most part I use hide-a-bevel .
Thanks
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Ok fellow opticians,
When should I use a 1/3 to 2/3 bevel versus at 50/50 or a layover.
For the most part I use hide-a-bevel .
Thanks
hide on most. only only high myopes do we do 1/3 (-4.00) in metal. satin polish, baby.
Autumn Eyes,Quote:
Originally Posted by autumneyes
It depends on the frame and patient, its just a matter of preference. Labs usually bevel minus lenses on the front of the lens, but edge plus lenses on center as a common standard.
The numbers refer to where the bevel is edged in relation to the front and back of the lens.
A 1/3-2/3 bevel will push the lens out the front to lessen the amount showing out the back. So it will create the ILLUSION the lens is not as thick (I will actually order a 20/80). Its a poor man's way around using high index lenses. Some of the lens (1/3) will show out of the front of the frame so polish is recommended.
In high minus lenses I will sometimes order 10/90 to lessen backside a little and move front edge of the lens to line up with the frame. It can shave 1 mm off the back without decreasing the front cosmetics at all.
I only order 50/50 when its really high minus and the lens would actually be too close to the patient (vertex distance causing RX issues) if it was hide-a-beveled. Have not done one in years.
I actually have no idea what a layover bevel is...
Sharpstick
To ensure proper fit and cosmetics, we just match the frame and lens curve to ensure a front bevel is possible and keeps the shape of the frame as natural as possible.Quote:
Originally Posted by autumneyes
We compensate the optics for each pair of glasses to ensure a 4 base frame gets a 4 base lens.
It works for us.
Craig
Quote:
Originally Posted by Craig
I can only assume you also only allow certain rxs to go into 4bc frames.
What if I'm a +4.00? Would you really make my lenses on a 4 bc?
HMMM
Anyone here ever heard of bending and arcing the chassis to fit the base of the lens instead of the other way around?
Chip
That's waaay beyond some people.Quote:
Originally Posted by chip anderson
Lotta younguns here....Quote:
Originally Posted by chip anderson
Us oldtimers had no choice but to manipulate the frame.:D
I was under impression that this was standard procedure..........at least that what I had learned.Quote:
Originally Posted by chip anderson
For best cosmetic appearance in plastic frame with no reflectance from the bevel on thick minus lens edges we made a flat bevel, then did a did a double groove. First with the nylon groover then enlarged it a bit with the Balgrip edging stone ............and you had the best looking mount you can get on thick edges.
I don't see an answer to the question - what is a layover bevel?
Welcome to Optiboard.Quote:
Originally Posted by Turtle3777
I've heard it described as a lay-over or lay-back bevel, similar to a very heavy edge roll, maybe as severe as a V bevel, on the backside only. From a birds-eye view, looking at the left lens, like this \ temporally, and this / nasally. It looks terrible from the front so avoid at all costs, but might be required if blank thickness is insufficient, or if you need the lens to clear the pad or pad arms, or to allow the temples to close.
Hope this helps,
Robert Martellaro
Wish more labs used a 10/90 as a standard, and used much smaller and *sharper* bevels. Ironically, the best lab I've seen for bevel work like this is VSP Folsom/Sacramento. Although the rest of their service ranges from sketchy to five alarm dumpster fire. :)
Depends on your edger and the RX of the lens and the curvature of the frame. All must be taken into account.Quote:
Originally Posted by autumneyes
1/3 bevel is for higher minuses. I would consider a 1/3 when the RX starts to approach -3.00 and up. What this will do is minimize the thickness on the back side while allowing some of that thickness to show in the front. Below a -6.00 that added bit in the front looks fine.
50/50 is good for low minuses and pluses between +1.00&-1.00. I sometimes use it for safety specs regardless of RX. I was told that it increases the impact resistance, but that might be an old benchman's tale.
Never heard of a 2/3 or layover. My understanding is hide-a-bevel is a type of finishing wheel in use by most edging systems now that allows the bevel to be relatively flat across the sides of the lens except for where the bevel v is.
Like this: __/\__ as opposed to a v bevel which was a hand finishing technique where the bevel slope started at the front sloped up to the apex and then sloped down to the back of the lens so there were no flats on the side of the lens like this: ./\. So everyone with a modern patterned or patternless edger gets hide-a-bevel unless you're hand finishing your lenses.
My 2¢. Generally 10/90 is only good for finished lenses with a high base curve (Gentex) and Sunglasses. If you use it all over on clear lenses it makes the lenses look sunken into the frame and off somehow. Your edgers auto setting is better in most cases excepting the instances I mentioned above.Quote:
Originally Posted by Uilleann
I'm having difficulty determining if you are being facetious or genuine in your question. Follow this link.Quote:
Originally Posted by chip anderson
Not a fan of 50/50.Quote:
Originally Posted by Kujiradesu
Much of the edger settings are based on the frame and RX.
Most of the auto settings on our edgers produce great results. To balance front/back cosmetics, we use 25% or 33% bevel depending on the frame. Polarized, of course, get a front bevel, normally at 1mm. Sport frames and some sun frames get a front bevel with a step back to clear the back bezel.
The rest is up to optician based on the order notes.
I think that the most important thing here is not from the bench side, but starts with the proper RX/Frame match. A -8.00 in 58mm/7 base sun frame is not a particularly wise choice, yet we see this often in our labs. And please don't return a -6 1.67 with a +7 OC in a nylor saying that the ET is too thick.
Or use the pan hard rod to control the bevel.........Quote:
Originally Posted by OpticLabRat
Absolutely!!! "Why do my sunglasses look like that? They didnt look like that when I bought them!" Its the RX stupid. If youre good, you can make the 1 in 100 that you cant talk them out of look good (putting what you can on a 6bc).Quote:
Originally Posted by lensmanmd
Lenses should almost NEVER project out the front of a frame. Nor should they be ringed with such a horrifically large bevel, as to cause the front of the lens to look like a beveled edge mirror. There should NOT be a bevel ring visible from the front of the glasses on 95% of SRx's that pass across our desks. That's where the 10/90 can be helpful. And lest face it, most larger offices who are using various wholesale labs cannot count on those labs to understand even basic cosmetics, or to be bothered to so much as read any special instructions. The breakdown in communication between the dispensing desk and the surfacer/edger is staggering. And sadly, only getting worse.Quote:
Originally Posted by Kujiradesu
Just a vent on my end of course - nothing will change, unless it's to just keep getting more and more cosmetically poor due to quantity over quality.
As much as I want to agree with you, keep in mind that wholesale labs are under a lot of pressure to stay competitive, and stay in business. Automation is a fact of life in most large labs, as it reduces labor and processing costs. It's about viability and staying alive in this new business environment. Gone are the days of manual processing.Quote:
Originally Posted by Uilleann
We do understand cosmetics, and we also understand best fit. Sell a high + in a 4BC frame and we will do our best to make sure that 8BC lens will fit the frame. Sell a high - in 6BC frame, we will do our best to fit that flat base in it. It may take custom bevel, and it may cost you a bit more. Realistically, it won't matter. You won't like it. I'm sure that you wouldn't do this, but we see it all day long.
We are more than willing to process special requests, but if you don't communicate your needs with us, you will get auto bevels in most cases. It really is up to the ordering opticians to specify BCs and bevel requests, along with any other special requests. Outside of that, it is up to you to order uncuts and finish them yourself if you are that particular.
In a perfect world, all of the RXs and frames will properly match. PDs and OCs will be properly centered. We won't see +10 vert on PALs. We won't see 10mm hor decentrations. We won't see +4 w/+3 add FF requesting a 4bc lens.
Just a vent from the lab end, of course. We are here to provide the best possible service to you. At least, my lab is.
In many of these ZYL or rigid flat metal styles of which the there is no adjustable part of the hinge, I will definitely edge a high minus lens with some of it poking out the front, in order to maintain the curve of the frame front. There is no otherway, and I think it looks fine, I've never had a patient complain, except for the lady with the -9.00 -4.75 cyl who wanted to know why part of the lens was sticking out on only one corner of her sunglass frame. In her case I wish my employee had put their foot down and forced her to choose a different frame, but alas...