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Thread: DIY Handheld Laser Cylindrical Lens Pair Mount How To !

  1. #1
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    Default DIY Handheld Laser Cylindrical Lens Pair Mount How To !

    PART 1




    So you've decided to use a Cylindrical Lens Pair with your handheld laser to tame the wild fast axis seen with a lot of the higher power multi-mode diodes, Great but the next thing is what lens pair should you get ?


    Well the two most popular makers of lens pairs are OPT Lasers and LSP and this is what you will get when you order a set...


    First is OPT lasers measuring at 12mm x 12mm....





    Next up is LSP with the only important measurement being it's height and as it turns out it's also 12mm !





    So here is both pairs side by side with both standing tall at 12mm but more on that later...





    Now the next and much more difficult question is how do i mount them to my laser and what is needed in a mount to use the lens pair correctly ?


    Cylindrical lens pair mounts used with handheld lasers are typically rather bulky and heavy relatively speaking not to mention some mounts require you to make a mount to mount the mount on in order to put the lenses where they need to be, In front of the diode ! like these....









    And to be honest they aren't very user friendly to add to your handheld unless you can make or have someone make a mount from those mounts like this....





    But i've came up with a small, light weight cylindrical lens pair mount that is much more easy to make and use compared to those other mounts and best of all if you use parts that a lot of us already use when doing a handheld laser build this mount is very easy to add to a handheld laser build !


    Let's start with the laser diode module that is needed to make this mount..


    A DTR 25mm copper diode module is needed with the diode of your choice intalled, More on that later.....





    Next you'll need to get two sizes of aluminum tube stock in any length you want but it wouldn't require very much of each length, The first size is 30mm OD x 25mm ID.....





    And the next is 25mm OD x 22.50mm ID which is a typical ID size for 25mm OD tubing......





    The DTR 25mm will in most cases slide right into the 30mm OD tube stock without any work to either of them.....





    But for the 25mm OD tubing to slide into the 30mm OD tubing a bit of sanding will most likely be needed....


    Because the typical length of "30mm" OD aluminum tube stock is approx 30.25mm OD and 25.10mm ID.


    And the typical length of "25mm" OD aluminum tube stock is approx 25.15mm OD and 22.50mm ID


    So some sanding to either the ID of the 30mm tubing OR some sanding to the OD of the 25mm tubing OR a little bit to both...


    And when you sand enough they will slide together like this !





    But be careful because aluminum can very easily seize to each other when rubbed together so use a touch of anti-seize compound between them !


    Now let me explain something that just happens to make this type of mount work well with lenses that happen to be 12mm tall !


    Here are some serendipitous facts that come together to make this all work !


    The 12.0mm cyl lens height + the shelf height of 5.50mm when using chunks of a typical machinist's 6 inch steel ruler as the shelf which is approx between 19.05 to 19.15mm wide with the chunks laid down inside the 25mm tube = 17.50mm subtracted from the tube ID of 22.50mm and will look something like this.....





    As you can see when using a cylindrical lens pair that is 12mm tall this cylindrical lens pair mount places the cylindrical lens pair nearly in the center of the 25mm tube because the space above the shelf + the 12mm tall cyl lenses is only 5.0mm which = the amount of cyl lens off set of 0.50mm which is very small and really not important because it will have no effect on how well the mount will work or interfere with the alignment of the lens pair but more on than later.....


    Another convenient fact is a typical machinist's 6 inch steel ruler (which you will need to get) is approx between 19.05 to 19.15mm wide for what reasons unknown to me, And they are very tough and fairly rigid and can be cut into small sections which you will need later....






    The next thing you need to do is cut down the length of the 30mm tubing approx 44mm which give enough room for the DTR 25mm module to slide into it at 32mm long and leave enough tubing for the 25mm tubing to also slide into it like this....





    Next cut the 25mm tubing down to appox 52mm which will give you enough space to slide any pair of lenses you choice to use together or away from each other to focus them VERY IMPORTANT DON"T CUT OFF THE END OF THE 25MM TUBE YOU ALREADY SANDED WHICH ALLOWS THE 25MM TUBE TO SLIDE INTO THE 30MM TUBE, MAKE SURE YOU CUT OFF THE UN-SANDED SIDE OF THE 25MM TUBE !!!


    Next you will need to get some JB Weld or equivalent epoxy and two ink pen refills like these....






    You could use the plastic if you had to but i highly suggest you get two of the metal refills because they are rigid and stay very straight when you do what is next, Glue them into place by laying your 6 inch machinist's steel ruler that i told you to get earlier inside the 25mm tubing and use two rubber bands to hold each ink pen refill down on both the tubing wall and the sides of the machinist's steel ruler which will look something like this.....




    This design places the


    Then mix up some of your epoxy of choice and epoxy the two pen refills to the tubing wall like these cross section pics shows how and where to put the epoxy.....






    After the epoxy has had plenty of time to cure remove the rubber bands....





    And trim the ink pen refills flush with the tube like this...






    BUT CAUTION if you are using new refills they of course will be full of ink so take precautions to contain any ink that may escape during the trimming and have a bit of acetone or equivalent handy to wash the ink out of the cut off refills !


    Part 2 Coming soon !
    Last edited by Wavelength; 09-21-2017 at 16:52.

  2. #2
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    To save messing about with inky pen refills, go to a craft or model store and look for the K&S Metals rack, you'll find an array of different size tubing in useful lengths (I think it comes in 13" but also available in 36" IIRC).
    Useful thread BTW

  3. #3
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    Quote Originally Posted by NobleGas View Post
    To save messing about with inky pen refills, go to a craft or model store and look for the K&S Metals rack, you'll find an array of different size tubing in useful lengths (I think it comes in 13" but also available in 36" IIRC).
    Useful thread BTW
    Thank you, Good tip !

  4. #4
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    Nice write up. One thing I found was the distance from the diode to the first cyl lens can make a difference in the final beam and most import to me cuz I do graphics the near field beam. Also the focus of the diode one the first lens is important. Nothing anyone doesn't know but important to remember. Nice machine work Alot of good engineering skills.
    Thank you for sharing. We don't see nearly the number of builds we use to see.

  5. #5

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    The guy does have some skills as a builder. A pity his lack of social skills keeps getting him booted from forum after forum. I watched his career over @ LPF with some amusement and hoped he would learn to get along but...he was never able to accept criticism of any kind. No matter how well-intentioned or kindly offered. I worry a bit about what he'll do in the future (accidentally or intentionally) with his beam corrected 8 watt handheld that starts fires @ 50'.

    Oh well, back to my status as a lurker here. I'm finding this forum much more useful and enjoyable than I used to. My handhelds are fun but they get a bit boring after a while. I really enjoy lumia, and I'm just starting to play with scanners. I'll contribute more in the future when I've learned enough to ask questions I can't find answers to using the search bar.

  6. #6
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    This was an informative post and good job. I have a cyndrilical lens pair from op lasers too but it may be easier to just buy parts from thor labs if you are designing this for a handheld laser.

    Example part list.
    IMG_20171112_164247_9543.jpg

    While being said, I wouldn't mind making something like this to mount my lens. Thanks for ideas. From what I've seen playing with the 12mm lens pair from op lasers, at least for a hand held laser it would be easier to make adjustments with a lens tube from thorlabs but...and I combed the entire internet, you can't find any source for 12mm x 12mm lens mounts. The problem is that the lens may have to be turned and aligned inside the tube.
    Ok you're dealing with a rectangular beam - and want a dot .
    So you would have to adjust the foucus at the diode - in addition to aligning the lens.

    When I build my beam correction, I will only use an arbor press to press the diodes into the can. I got no complaints on my sources but I noticed some are just off centered enough to make a difference. In some cases diode manufacturer defects.
    Personal notes holy ********* that little baby will burn!

    I'm questioning another option on beam correction for lower powered diodes by inverting the standard lens and putting an adapter from 12mm to a sanwu 3x beam expander. It may not be as professional but may work.
    Last edited by Bradford7175; 11-12-2017 at 15:23.

  7. Default

    Great tutorial, thanks a lot. Looks like I'll need to buy a few more things before assembling my own kinda handheldy laser.
    "Hey, Mr. Cat, could you bring me some padded envelopes?" - Postman Pat

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