Drill Hole Fractures

**judyseyes** · 02-19-2004, 10:01 PM

My Optician friend is using one lab for all his drill mounts. He has tried Poly, 1.6, and now the lab is telling him to switch to plastic material. The fractures show up 60 to 120 days after delivery to the patient. What's really going on? Is it the material, drill operator, equipment or all of the above?? Thanks.

**Clive Noble** · 02-20-2004, 12:00 AM

I think.... Switch labs or start doing it yourself properly. I had lab probs all the time 'till I bought the equipment and taught myself what to do

CR39 is just great material.... the best, but not for screwed rimlesses....OK it can be done, but you're more likely to see it back broken than if it were Poly.

Phoenix is proving itself with us, no cracking, no splits, and hardly any rejections as with Poly.

Final thoughts, the lab might be drilling with blunt drill bits, or at too high a speed, or simply screwing up too tight. Are they using all the correct washers and spacers?

**Pete Hanlin** · 02-20-2004, 07:57 AM

Final thoughts, the lab might be drilling with blunt drill bits, or at too high a speed, or simply screwing up too tight. Are they using all the correct washers and spacers?
Clive has hit on nearly every pertinent issue in this one sentence. If polycarbonate lenses- or 1.60 / 1.67- are cracking, there is something wrong with the drilling process or mounting.

For polycarbonate (and Trivex), a sharp bit or reamer must be used at slow speeds. For these materials, the enemy is heat. For all materials, the holes must be chamfered (a bevel should be placed on the edge of the hole which will eliminate the micro cracks in the SRC and ARC around the hole periphery).

Also, it is very important that holes are created the exact right size and in precisely the correct location. Any wobble in the mounting will eventually lead to breakage.

Finally, it is absolutely crucial that bushings- where indicated- are used. Mate metal with any resin and the metal will win over time. Any material (yes, even Trivex) can fail over time if improperly mounted. If you are limiting yourself on material selection simply because your drill mounts are failing, you are needlessly limiting your options in how to best meet your patient's needs and desires. Poly, 1.60, 1.67, and Trivex can all be drill-mounted with very high degrees of success if the drill and mount processes are done correctly.

**igirl** · 02-20-2004, 08:52 AM

I would absolutely, never ever, use plastic in a drill mount. It is a recipe for disaster and an unhappy patient. Clive and Pete covered it all and are right.

My final suggestion would be having your friend contact other labs and question them about their drilling procedures. If they mention the procedures in Pete's post, he will probably be on the right track. There is a new Rimless Council being formed and soon you will see which labs are Rimless Certified by Colts in several of the major optical mags.

**Laurie** · 02-20-2004, 09:45 AM

I completely agree on not using CR-39 for drillmounts...

Even though I insisted on CR-39 for one of my own pair (I am not comfortable with my vision through poly) it broke shortly after. Now that I have remade them with TRIVEX material, I am very happy with them.

I would stick to TRIVEX for all rimless. It has the strength of poly, with far superior optics. As much as some opticians think that ABBE value and Chromatic Aberrations don't matter, science has proven otherwise. The slightly dulled image that I can detect with polycarb is due to chromatic aberration inherent in the material. And, my Rx is simple (-1.00 sphere OU). Imagine the differences in higher powered lenses! I would give TRIVEX a try whenever you would consider poly...your patients will love the difference.

Have a fun day,

: )

Laurie

**Pete Hanlin** · 02-20-2004, 11:43 AM

Actually, although there are certainly better materials for drill mounts available, I have worn a drill mounted pair of CR-39 sunglasses for some time with no lens failure. This pair of glasses gets sat on, clipped to the sunvisor of my car (in Florida heat, no less), and basically exposed to all sorts of ungodly wear and tear.

My point is not that we should all go out and drill CR-39. Rather, I believe we need to all step back and note that the skill level for processing drill mounts has fallen dramatically. Working in Lancaster, PA, I saw dozens of glass drill mounts worn by Amish people (who may be gentle in demeanor but are by no means gentle with their eyewear). Very few were chipped or cracked lenses. (Note, I didn't provide these lenses- I merely adjusted, tightened the occasional screw, etc.) Point being, even glass will be durable when properly drilled and mounted.

Is Trivex a material with very good drill mount properties? Sure. However, if you are having lens failures with polycarbonate or high index lenses, Trivex will only be hiding what must be poor drilling technique (and even Trivex will not hide these faults forever). It seems to me there is a choice- improve the quality of the mounting (which will result in sturdier and safer eyewear), or "mask" the problem by limiting yourself to a marginal material (marginal from an availability standpoint, that is).

PS- Since the optical quality theme has been brought up, if you can actually tell a qualitative difference between Trivex and other lower abbe thin products (1.67, 1.60, polycarbonate), by all means wear it in whatever designs it is available in. Of course, if chromatic dispersion effects you that much, you might want to stick with CR-39, which is available in virtually all PAL designs and has a considerably higher abbe value than Trivex.

**For-Life** · 02-20-2004, 11:56 AM

Try using OMS Edgit.

It is a solution that you drop in the holes that will seal up all of the tiny fractures; therefore, they will not spread. We had that problem and that is what we are now using (or our lab is using).

Of course, I have no affliation to OMS.

**EyeManFla** · 02-20-2004, 02:17 PM

I currently have three drilled rimless eyeglasses that I switch around, depending on the day. One is a Neostyle and two of them are Cazals.

All three are Panamics in CR-39. (If I had an old Unichuck drill, I'd do em in glass).

I have generally found is that the biggest problem with mounting 3-piece rimless is that labs go out, spend $20,000 for a machine and get some $5.00 an hour tech to drill them!

Yes, believe it or not, there still is some skill involved in this process. I do not carry Revolution Airs because the BIG Essilor lab up the street from me couldn't drill them right if you held a gun to their heads.

Most of the time, most lab tech just forget, or were not trained, to reem out the drill holes before they mount the lens.

**Jedi** · 02-20-2004, 02:26 PM

I agree with Pete, If you have a skilled lab tech you should have any problems in any material. With that being said, looking at the type of drill mounts you are selling will affect the durabilty of the lens. Hands down the Silhouette Minimal Art is the best mounting system for a rimless frame. We are happy with the lenses that come from our lab whether it is CR-39 mid or high index, we rarely use poly (too many bad experiences in the past) and trivex doesn't fill a niche for us yet. If anyone in the Calgary area is having problems with rimless frame call Philip Tram @ Doctor's Optical 403-250-1314. He is such a perfectionist it make my life so
easy.

**Chris Ryser** · 02-20-2004, 03:42 PM

For polycarbonate (and Trivex), a sharp bit or reamer must be used at slow speeds. For these materials, the enemy is heat. For all materials, the holes must be chamfered (a bevel should be placed on the edge of the hole which will eliminate the micro cracks in the SRC and ARC around the hole periphery).

Pete,

Talking about drilling, "they must have drilled you at ESSILOR" to just about come out with the right answers.

In my time I have drilled holes in lenses from the old German style Nose Clippers (see in old movies) to Newmounts, Wilsedge and Balgrips before grooving Nylor frames.

The drilling was done withan optical drill which contained a diamond and we used linseed oil to cool the diamond and glass while slowly drilling otherwise the lens would crack or the diamond burn up. It used to be quite a job to drill a -8.oo D lens in flint for a 2 or 4 hole Newmount.

It was a must to safety bevel the edes of the hole and see that there was no tension from the screws and the top bar of the frame.

Doing rimless mountings is a precision job and should be looked at as such.

Pete has given a perfect description how to do it, but there are many in the field that do it their own way like with everything else.

For-Life has given one of my products a nice recommendation and I thank you for it. I usually do not use the Optiboard to push any of my products. The product mentioned by For-Life post is one of ours and will seal any microscopic cracks occuring during drilling polycarbonate. It also comes in clear or very light colours so you get a clear or pastel coloured hole that won't crack.

**chip anderson** · 02-20-2004, 08:47 PM

igirl:

If you don't use plastic, what do you use? Glass is illegal and quartz isn''t available any more. Note: CR-39, Poly, Trivex, Polyurathane, and almost anything else used for lenses is plastic.

Different plastics to be sure, but all plastics.

Chip

**judyseyes** · 02-22-2004, 09:17 PM

Chris

Can the lab use your solution as a "preventative" to cracks??
Thanks to all responses!! Judy

**Chris Ryser** · 02-23-2004, 04:18 AM

judyseyes said:
Chris

Can the lab use your solution as a "preventative" to cracks??
Thanks to all responses!! Judy

Judyseyes,

Anybody who drills and does mountings can use it if they know it exist's.
After drilling apply onedrop into the hole will seal all microscopic cracks and dry in seconds. It's really no big deal and easily available from my company. Go on my website scroll down the home page to Edgit and click on the link for full details.

**Livy** · 03-03-2004, 06:18 PM

Just a final thought, no amount of care and attention or top hats (As we call them this side of the pond) will stop a poly from cracking if some one at the optician's uses liberal amounts of solvent to clean them.

You can literally see the cracks move before your eyes ! Have you also noticed how people think it's cool to remove a rimless with one hand ?

**Eddie G's** · 03-04-2004, 07:46 AM

I always use CR-39 on rimless frames and I've had no problems!

Actually I just received a broken TL16 lens in an Oakley rimless (after 2 years) but the patient stepped on them.

Still NO poly's/ trivex for me!

But I did notice that our Zeiss lab is now carrying trivex.

**igirl** · 03-04-2004, 10:32 PM

chip anderson said:
igirl:

If you don't use plastic, what do you use? Glass is illegal and quartz isn''t available any more. Note: CR-39, Poly, Trivex, Polyurathane, and almost anything else used for lenses is plastic.

Different plastics to be sure, but all plastics.

Chip

Point taken, however, most that I deal with in the industry find the term plastic to be interchangable with CR-39.

I recommend poly, mid-index or higher. For everyone who has had good luck with plastic (CR-39), great! But I've only experianced heartache.:(

**For-Life** · 06-23-2004, 03:08 PM

Originally Posted by Chris Ryser

For polycarbonate (and Trivex), a sharp bit or reamer must be used at slow speeds. For these materials, the enemy is heat. For all materials, the holes must be chamfered (a bevel should be placed on the edge of the hole which will eliminate the micro cracks in the SRC and ARC around the hole periphery).

Pete,

Talking about drilling, "they must have drilled you at ESSILOR" to just about come out with the right answers.

In my time I have drilled holes in lenses from the old German style Nose Clippers (see in old movies) to Newmounts, Wilsedge and Balgrips before grooving Nylor frames.

The drilling was done withan optical drill which contained a diamond and we used linseed oil to cool the diamond and glass while slowly drilling otherwise the lens would crack or the diamond burn up. It used to be quite a job to drill a -8.oo D lens in flint for a 2 or 4 hole Newmount.

It was a must to safety bevel the edes of the hole and see that there was no tension from the screws and the top bar of the frame.

Doing rimless mountings is a precision job and should be looked at as such.

Pete has given a perfect description how to do it, but there are many in the field that do it their own way like with everything else.

For-Life has given one of my products a nice recommendation and I thank you for it. I usually do not use the Optiboard to push any of my products. The product mentioned by For-Life post is one of ours and will seal any microscopic cracks occuring during drilling polycarbonate. It also comes in clear or very light colours so you get a clear or pastel coloured hole that won't crack.

Bump!

Just giving an update. My lab and I have been using this product since the beginning of the year and the cracking has stopped. Everyone I had troubles with and have used this product have not had a problem since.

**Pete Hanlin** · 06-25-2004, 07:40 AM

Thanks for the info on Chris' product, For-Life. Being in Technical Services, I get a lot of inquiries regarding cracked drill mounts. Although proper technique is still what I consider paramount, any product that can improve the performance of even less-than-optimally processed DMEs is certainly welcome!

Given that you've had real life dispensing experience with the product, that's a pretty strong testimonial. Can you tell me what materials you have used the product on so far?

**harry a saake** · 06-25-2004, 03:58 PM

Chris Ryser, how do you drill a balgrip

**mrba** · 06-25-2004, 04:17 PM

For polycarbonate (and Trivex), a sharp bit or reamer must be used at slow speeds. For these materials, the enemy is heat.

Actually this is for if you are drilling in the dark ages.

What manufacturers do not want you to know is that the polycarbonate itself can be defective in that it will crack, sometimes in a full frame!

Labs should also stop using old fashoned drill bits, and motors that have too much vibration. Use the spacers and washers. Use carbide drills at any speed you want!

Also in our expirience we have had trouble irregardless of technique with Gentex poly (owned by you guessed it, Essilor). It cracks all every time.
If you do a lot of drill mounts in Poly Essilor product and have problems, try another brand and prove my opinion wrong.

**Chris Ryser** · 06-26-2004, 03:30 AM

Originally Posted by harry a saake

Chris Ryser, how do you drill a balgrip

Harry,

I just love this question, and here is my answer for all you guy's that are too young to know it.

You Can Not Drill An Old Balgrip Unless You Drill The Holes For The Temple Screws

Bausch & Lombs "Balgrip frames were the most popular rimless frames worldwide in the 1950's and early 1960's until the Nylor frames made by Essilor took over.

As long as you followed the eyebrow curved on the Balgrip you could make any shape lens you wanted. The grips were soldered to the bar, one close to the temple and the other close to the nose pads.

You would notch the lens for the grips, and then bend the grips to fit the edge thickness of the lens and cut off the excess lenght of the grips. And that was all done with good old (mineral) glass lenses.

**Chris Ryser** · 06-26-2004, 03:42 AM

Originally Posted by mrba

Also in our expirience we have had trouble irregardless of technique with Gentex poly (owned by you guessed it, Essilor). It cracks all every time.

If you do a lot of drill mounts in Poly Essilor product and have problems, try another brand and prove my opinion wrong.

mrbs,

If you would have read all the postings you would at least have to admit that you should use or try every technique available, before making above statements.

One single drop of "OMS Polycarbonate Edge" into a drill hole, and never mind which type drill made the hole, will seal all the cracks that occur while drilling and will start to craze later on.

Therefore there is a simple solution available that does not cost a fortune and solves the problem once and for all.