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Cylindrial lens cutting - is it possible?

RA_pierce

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I've done some lens shaping with a fine diamond file and water. It's a tedious process but it does work. Just be sure to mask the optical surfaces you want to keep... optical.

I've made round lenses rectangular and even reduced the diameter of a wedge prism so it would fit one of my projects.
Just pay attention and be careful.

I'd probably go for a very small diamond coated needle file for splitting a cylindrical lens. Power tools run the risk of grabbing the lens and launching it into orbit.

Maybe practice or experiment on a similar but less valuable item first.
 



CDBEAM777

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Hmmmmm....????? SO....Shaping B7 glass is doable....but has issues. The biggest issue is that you may end up scratching the optic....then you have junk.)
Let me take a guess here....You may have a round host....and have a set of C-Lenses that are 23mm x 18mm....SO....problem is....you want to use this lens pair...in a host....that is too compact to set up the C-Lenses....MMMMmmmm...AKA a " Blivitz"....10 lbs of SH$T....in a 8 lbs SH$T bag !!!.....What to do. ??????
1) Get a larger host
2) Buy a round pair of C-Lenses ( at about 150 bucks !!!hahahaha)
3) "Grind yer own " lenses

SO....if you DO wanna try " Door #3 ".........Some thoughts...

1) Make an Octagon vs a Circle.

2) Protecting the Optic from scratches is critical. I would get use masking tape and draw a Octagon shape on the tape B4 you apply. This would protect the optic while you are grinding away.

3) I think....maybe a Dremmel tool...clamped in a vice....with a 3" Diamond blade would " Slice'n'dice your glass.

4) Have some arrangement where a supply of fresh water would be flowing atop your blade ( Messy....but necessary !!!)

5) So...maybe yer lucky....and need to slice off only four (4) corners.....AND the top = and Octagon which is 18mm x18mm !!! An Octagon which you have cut FIVE (5) sides.....and left the bottom untouched !!!! SO....you end up with an Octogon shape.....18mm x 18mm !!! With one (1) side original.

6) Last step would be to Epoxy the lenses to an Aluminum mount (strip....to set the distance between lenses and also deliver the correct Pitch and Yaw ........Remember....you have ONE untouched surface.....and THIS should allow you to position and fix the correct Pitch and yaw !!!

7) Now,.....THIS Lens+ Lens + Mount MAY be small enough to fit in the Host tube.

If it were me....I would go to my local Glass shop....and buy a few scrap pcs of 1/4" thick glass ....maybe 5/8" wide x 12"....and have the score and sell you 1" long pcs.....to practice on.....should be really cheap !!!......and after some practice.....try out on the lenses !!!

Just some thoughts.....NO EXTRA CHARGE. I have cut C-lenses this way..( Just in half )..some have chipped slightly !! A risk.....yes....well..... then you have other more $$$ options

CDBeam
 

Shotgundrums

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Thanks for all the replies and infos. You guessed it... round host. Not critical though. I can work this into a bigger host. I may try to load the lens pair against a rounded base to fit a tube.
SGD🥃
 

RedCowboy

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The c-lens sets techhood sells are very small, I have some but have only done a quick test with them. 7mm x 8mm



 

CDBEAM777

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Yea...I like this tiny diamond saw. Hmmmm...betcha one could just buy blade.... mount it on a good scroll saw.....and " Cut the Cheese "....er that way HHAHA !! or get the 7mm x 8mm Techood lenses. BUT..........IF you think....trying to get the fair size 6X in near perfect alignment is a BITCH....wait till'ya try those little tiny units.....!!!!!!!!!!!!! It will be like pushing a raisin around !!! My speculation....if the lens is smaller...the optical "Sweet Spot " will be smaller....and therefore....much more tedious to find !!!!!!!!! IIRC...I used a small set in the Red Dragon build....and getting the alignment good was a real hoot !!! One can do it....just a real PITA !!

Note: There IS another way. Many, many years ago...I was a member of the Toledo Glass Blowers Guild. The final piece prep involved grinding the work bottom flat and perpendicular to the work axis. It was a process that used a large diameter spinning steel platter...about 1" x 18" in diameter. We used fine Diamond paste....and the grinding work went fairly quick....in the end....the piece had a really flat bottom. The platter had a water drip and spun about 60 RPM. Basically a Lapidary Gem cutters wheel...with the work done free hand. You could check for any local Gem Cutter groups !!! They would do it for real low $$....and you would have fun watching the process....Might take 1/2 hour to do In THIS method...protecting the optics working area would become even more critical !!!...Any tiny scratches will give you junk !!
I am not surprised a Eyeglass shop said no way...Their units are all automated....no hand work at all....NOT set up for anything...other than eyeglasses !! Have Fun !!! As with most projects...there is typically a workaround !!
 
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paul1598419

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Back in the late 1960s those lapidary wheels were at least $400 as I was into that. I imagine they are very expensive now.
 

Shotgundrums

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The c-lens sets techhood sells are very small, I have some but have only done a quick test with them. 7mm x 8mm



I have some of these in red spectrum. I tried to correct an Oclaro 700mW 638nm with them, they did ok with correcting the divergence. Not terrific. Correcting lower divergent diodes like m140, and NDG7475 is pretty good though.
SGD🥃
 

CDBEAM777

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Back in the late 1960s those lapidary wheels were at least $400 as I was into that. I imagine they are very expensive now.
Yea....Gem Cutting equipment t IS expensive....Sigh....That is why would be best to look for local group to do the grinding....if one went that way !!
I have found....typically....they are most pleased to help !!! Many of these groups have been around for decades....and have accumulated much equipment and practical experience in how to use it !! Optical B7 glass is nothing special....when it comes to grinding a flat/unpolished surface.
I predict.....the easiest and least expensive path....is to get with the local Artesian Guild....They are passionate, sharing, have tools and experience....and usual inexpensive !!! Seems to me....partner with them for such a small....and novel project. I bet they will be a pleasure to work with !! Just my take. A Grinding wheel ...as I described is a very basic tool in any Glass Workshop. Diamond paste is expensive....but....likely the use would be extremely small.... Bob

Added thought...For protection of the optic during the grinding operation....coat both sides with the product called " First Contact ".... See here...


This forms a peel off mask....would protect and be easy to remove !! There....I have provided ALL the answers !!! HAHAHAHAHA !!! Ahhhh I am your .....

Arne Saknussemm

guide !!!
 
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RA_pierce

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I have some of these in red spectrum. I tried to correct an Oclaro 700mW 638nm with them, they did ok with correcting the divergence. Not terrific. Correcting lower divergent diodes like m140, and NDG7475 is pretty good though.
SGD🥃
That's odd. I was able to get divergence close to single-mode diodes with a pair of cylindrical lenses and a 1.2 W 638, which likely has a much larger emitting area.
Instead of expanding and then collimating the slow axis, I opted to collimate both the fast and slow axis individually with convex lenses.
This method eliminates the need for a separate aspheric collimator so that losses are minimized and the result is a much more compact correction setup. Edmund optics sells these lenses in circular format. You will have to determine the ideal focal lengths based on your diode and desired application, and then select the closest options from their stock. Occasionally some of their stock selection goes on sale.
My crude attempt did not achieve perfect alignment so the beam was ugly but I intend to give it another shot now that I've improved my skills in the shop, have gained some experience, and have better tools to work with.
See here: https://laserpointerforums.com/threads/optically-corrected-pen-mm-638-v1.102900/
 

Shotgundrums

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That's odd. I was able to get divergence close to single-mode diodes with a pair of cylindrical lenses and a 1.2 W 638, which likely has a much larger emitting area.
Instead of expanding and then collimating the slow axis, I opted to collimate both the fast and slow axis individually with convex lenses.
This method eliminates the need for a separate aspheric collimator so that losses are minimized and the result is a much more compact correction setup. Edmund optics sells these lenses in circular format. You will have to determine the ideal focal lengths based on your diode and desired application, and then select the closest options from their stock. Occasionally some of their stock selection goes on sale.
My crude attempt did not achieve perfect alignment so the beam was ugly but I intend to give it another shot now that I've improved my skills in the shop, have gained some experience, and have better tools to work with.
See here: https://laserpointerforums.com/threads/optically-corrected-pen-mm-638-v1.102900/
I’ll have to try that. I set the lens, diode module w/ G2, driver, switch, and battery all on a flat, long wood base. The lenses I used were the techhood pair shown above. The set came with two convex, and one concave. Perhaps I’ll try without the G2.
SGD🥃
 
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