G8 Solutions

[RedCowboy]

I believe Jordan went out and found a usable longer FL lens AR coated for the entire visible range and a threaded barrel that would work then assembles them himself for us hobbyist to enjoy, I don't think they are designed by a corporation, some fine tuning will likely follow in time if things go well, if not there are a lot of Chinese lenses to experiment with.
Luckily this is just a hobby and not so serious like so much we have going on today, that said if you build a better mousetrap they will come.


---edit---

You could add length to your module by drilling out the ends of the cheap silver 12mm modules or have Lifetime17 make you some threaded 12mm tubes and put your module and the extension in something like this >

You will want 2 set screws one for the module and one for the extension, I like using 8/32 setscrews as they hold up well and the larger taps are stronger and easier to use than the smaller sizes.

https://www.ebay.com/itm/5x-Aluminum-Heatsink-for-12mm-Laser-Module-Laser-Heat-Dispensation-Dvice/251044685895?_trkparms=aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=225074&meid=d9a6b88d411a492e9455d0fa0b3c753b&pid=100005&rk=1&rkt=12&mehot=sb&sd=261113766519&itm=251044685895&pmt=1&noa=0&pg=2047675&algv=SimplAMLv5PairwiseWebWithBBEV2bDemotion&_trksid=p2047675.c100005.m1851

 

[icecruncher]

I seem to remember in the back of my head a longer lens assembly that worked for some particular lenses. They were available from Ebay for a short while. It might have been the g8 but I can't remember for sure.

I bought a dozen or so and mounted the lenses I bought from Jordan for super cheap at the time. He was selling ones that needed to be cleaned up and mounted. Anyone remember if this was the G8 or what it was?

 

[RedCowboy]

I think that was the G9 which was a G2 doppelganger from projectors or it could have been something else but I don't know what.

 

[snakeyes]

@FireMyLaser Very, very cool array! Can we see a pic of your brass spacers in action?

@RA_pierce Is it difficult to "flip" the lens around and run a G8 backwards? Any tutorials anywhere, or advice? I'd like to give that the ole college try.

@Lifetime17 is it not possible to just machine a lens tube 4-6 mm longer then the usual?

What about one of Lifetimes focus wheels threaded all the way through with an empty tube on one side and the lens on the other?

Not trying to push the anyone's buttons, or any limits of the group. I'm mostly here to learn but when i ran into an issue i just assumed LPF as a community had a solution already..
Now that i know a little more about the G8 i'm just here to brainstorm and pick everyone's brain a little.

@RedCowboy When i hear "compromise" there is just something in me that goes crazy! Especially when its something mechanical or fabricated. There has to be some type of solution that i can do and there is a yearning in me to figure it out lol.

@ All -- Where does Jordan sell his goods? or how can i find what you speak of..

i mentioned earlier that i somehow cracked my G8... well i figured it out and it got worse.....

....

Not only did i crush my first G8 lens with less then 4 mins of combined usage, i crushed my first NDG7475 diode slightly.
not sure how i tightened the lens tube so tight or what exactly happened...
i am disappointed in myself. i'm hoping the diode casing just got a little bent and scratched, and that the actual diode isn't damaged at all. but i wont know anything until my next lens get here Wednesday and i can test it.. it lights up green but i don't know what its suppose to look like without a lens.

i ordered a bunch of back ups this time mostly from Lifetime17 -- 2E, 3E, G8, G2, G3, 3x Beam Expander

-- michael

 

[RA_pierce]

Its not hard to flip the lens.
It is easy to get the lens dirty, though.
The optic is held in place by a locking nut slotted for a small screwdriver or needle nose pliers. Be careful not to slip and stab the glass with a tool. The nut is held with an adhesive in some lenses so requires a bit of force or heat to break free. I have had good results with setting the lens on a ceramic heat lamp for one of my reptiles for a couple minutes.
If I recall correctly there is also a spacer. Keep a clean microfiber cloth handy as well as clean cotton swabs. I wear clean nitrile gloves and carefully use fine tip forceps when I handle optics. avoid touching the important surfaces of the lens by handling only the sides. A clean glove (cotton and uncoated latex or nitrile) is good enough if you dont have forceps.
Once you break the nut free, you can remove it and dump everything onto the cloth and reinstall the whole assembly but with the convex surface going in first. This can be tricky because if you just drop the lens in, it may flip around and reverse the desired orientation. Use dry cotton swabs to gently pick off any dust particles before reinstallation. Don't use your breath to "clean" a lens.
Just be careful and clean.

Install the lens in the module with the plano surface of the lens facing the diode.
Addendum: for short wavelength diodes, it may be necessary to shorten the lens assembly by filing down the threaded side of the tube. If this is necessary it should be done before the optics go back in the tube and any metal filings should be removed to prevent abrasion or particles getting onto the diode.

Its a pain in the ass but its a simple solution that works.

 

[RedCowboy]

Yes lenses get dirty easy, the natural oil on our skin will make a big difference, I had some G2's that were hazy and losing half the power until I cleaned the lenses and VIOLA full output and no haze, I use ZEISS microfiber lens wipes from wal-mart, they are inexpensive and work well.

 

[Lifetime17]

I like the G3 for single mode diodes as the G2 ( which has many uses and is a great lens ) makes a wider beam far field and a much bigger box artifact near field......the G8 is useful for many MM diodes and I use a drilled out module end to lock in my infinity focus but this is a hobby and sometimes we have to improvise, a longer module cavity may be needed for some diodes or just use a different lens.......I suppose a note that some diodes will need a longer threaded lens cavity than the " standard " would be a good inclusion in the G8 advert.

I have long wanted to see wider lenses and wider modules with wider and longer threaded cavities but we can make or have made what ever we want, however taking advantage of what's easily available and very affordable means knowing emitter geometry is different from diode to diode and divergence varies so not every lens available will work perfectly with every diode in the standard module.

Another thing I have done is to use a drilled out module end in my heat sink after the module, I have done this to use the sanwu G7 with some diodes in the past.

View attachment 69962

Hi Red,
Send me one of your famous CAD type drawings for this to follow please.
Rich

 

[snakeyes]

@RedCowboy I would like to see one of these CAD's too! What are you using to create these CAD's your famous for?

@RA_pierce thank you for the detail.. i appreciate all of it, i will take lots of photos with my attempt! the diode is NDG7475

 

[icecruncher]

I think that was the G9 which was a G2 doppelganger from projectors or it could have been something else but I don't know what.

Yeah that sounds familiar. G9 sounds right. I have a bunch buried with the longer lens assemblies.

And definitely agree on the Zeiss cleaners. Also work good on almost everything else.

 

[FireMyLaser]

The tube I got is not the right diameter so I made a split and expanded it to match the inside diameter of the threaded housing. I found that 4mm length made it work well with all single mode wavelengths. Making it longer makes it close to bottom out too soon for blues and violet, and making it shorter doesn't give as much thread engagement.

 

[RedCowboy]

Maybe a couple different length spacers with the right taper to fit against the lens and a longer lens barrel would be an easier way to go ?

There's also the width of the diodes output and getting all the light into the lens, so we kind of want the lens at the back of the barrel......this makes a longer module the right answer and it's why using a module extension in your heat sink is a easy fix for most as people usually put their modules into some kind of heat sink, this also means you can change it up later without pressing a diode in/out of different length modules or messing around with spacers and contaminating your lens, a module extension maybe 5-7mm long held in your heat sink by a 2nd set screw will work without changing everything else which could present other issues........I would still like to see wider/longer modules and wider longer FL lenses readily available someday however I am thankful we have what we do at prices we can afford.

 

[snakeyes]

The tube I got is not the right diameter so I made a split and expanded it to match the inside diameter of the threaded housing. I found that 4mm length made it work well with all single mode wavelengths. Making it longer makes it close to bottom out too soon for blues and violet, and making it shorter doesn't give as much thread engagement.

The G8 I got from dtr is the glued style, where can I purchase that style of G8

 

[RedCowboy]

My G8's unscrew and the lens is flat on one side which goes flat side towards the laser diode....the lens seat and the retainer face appear to both be flat.

If the lens barrel was longer and had no seat, just threaded all the way through, then a 2nd flat face retainer could be used on each side......simple......however I would use a shallow/short retainer for the input side and you can use a small wooden stick that fits through the hole ( tapered ) to screw them in easily until your desired position and use the longer/thicker retainer on the output side.

 

[snakeyes]

My G8's unscrew and the lens is flat on one side which goes flat side towards the laser diode....the lens seat and the retainer face appear to both be flat.

If the lens barrel was longer and had no seat, just threaded all the way through, then a 2nd flat face retainer could be used on each side......simple......however I would use a shallow/short retainer for the input side and you can use a small wooden stick that fits through the hole ( tapered ) to screw them in easily until your desired position and use the longer/thicker retainer on the output side.

oh Jeeze.. I feel dumb. Red your photos taught me a lot. I was confused and uneducated, I appreciate your posts per usual. That’s exactly how my G8 is, I just didn’t see that the inside was threaded. But this new info brings new ideas. What about using one of the inner retainers as a male to male coupler for two g8 tubes with only one lens.

 

[RedCowboy]

It's likely going to work out better to find some 9mm inner and outer threaded brass barrels, I know it's M9 x 0.5 on the outside and I suspect M8 or M7 @ 0.5 pitch on the inside and simply use 2 retainers to hold the lens at your desired position, because rather than buying a 2nd barrel to join and having the seat restriction, just buy one threaded all the way through and use thin retainers as wide open ( widest hole ) as is possible.

 

[FireMyLaser]

There's also the width of the diodes output and getting all the light into the lens, so we kind of want the lens at the back of the barrel......this makes a longer module the right answer

That's not how this work. Whether you extend the housing or move the lens further inside the lens holder with a spacer does not affect how much light it catches. It's just two different ways of placing the lens the exact same distance from the diode.