DIY Laser aligner

Discussion in 'Darkroom Equipment' started by Greg Davis, Apr 11, 2012.

  1. Greg Davis

    Greg Davis Member

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    I cannot justify paying $200 for a laser aligner for my enlarger, yet I cannot justify not having one at all. To that end, I decided to build my own. I admit I was inspired by the chapter in Way Beyond Monochrome showing a homemade one, but I made mine a little differently. First I needed a laser pointer. Radio Shack has one for $30, but my father-in-law said he had an ultrasound measuring tape he has never even taken out of the box that had a laser pointer in it. We cracked it open and took out the diode. We tested the battery power needed to turn it on and found it needed 3v, so I looked around and found a Christmas tea light that used a 3v watch battery and had an on/off switch. Next I needed a body to put it in, so I looked around my shop and found a 2 1/2 inch diameter chunk of acetal plastic, so I used that.

    I machined the plastic to the right length and faced the surfaces on my mini lathe, then drilled a small hole for the laser to shine through. I used an end mill to make the hole bigger for the actual diode to fit in, then bored the hole bigger for the battery holder and switch. Finally, I drilled and tapped three holes around the sides to accept set screws to make it possible to adjust the laser to perfect perpendicularity to the base rather than screws on the bottom as Ralph's book describes. I used some rubber cement to adhere the front of the diode to the hole and provide a flexible pivot point that the set screws could work against. The entire project took me 3 hours and cost $1.49.
     

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  2. Robert Hall

    Robert Hall Subscriber

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    Well done! that cost $298.49 less than mine did.
     
  3. Arkasha

    Arkasha Member

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    Interesting! Silly question - how do you plan on using it?
     
  4. pjbc

    pjbc Member

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    Hi,

    How do you know that the laser is perpendicular?

    Thank you,
    Paulo Cabrita
     
  5. paul ron

    paul ron Member

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    Nice job. I built one using a laser from a cheap pointer. Mounted it all in a nice metal chassis box with adjustable feet I carefully calibrated.

    To do my enlarger I put a first surface mirror in the neg holder n shoot through the lens opening. After that, I put a mirror in the lens board n adjust that. I do all this off the base board. Then after everything is perfectly aligned, I check to see that my easel is adjusted to my lens mirror.

    Oh BTW... check to see that when you raise n lower the head the unit stays aligned, that can cause havoc if the rack is out as you raise n lower. I wound up rebuilding all my bushings, fine tuning glide springs, squaring up the frame, bolting the enlarger to the table n wall, n making adjustments to the entire enlarger before I ever made a single picture. It's worth the trouble though.



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  6. Moopheus

    Moopheus Subscriber

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    Hmmm . . . I wonder if my cats will miss their laser pointer toy . . . .
     
  7. Greg Davis

    Greg Davis Member

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    Similar to the Versalab laser tool, it reflects back onto itself. When the dot reflects back into the hole it shines out of, then the enlarger is aligned. I am in charge of aligning all 30 enlargers at my university each semester, so I do a lot of this and love these tools. I wanted my own for home.
     
    Last edited by a moderator: Apr 12, 2012
  8. Greg Davis

    Greg Davis Member

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    If you reflect the dot off center (enlarger intentionally off axis), the the dot will be to the side of the original aperture. By turning the laser device you can watch if the dot wobbles or is stationary. If it wobbles as the unit is turned, it is not perpendicular. I adjusted the set screws until the dot remains stationary when the unit is turned in place (I used a block of wood with a v notch cut into it to turn the unit against without it sliding around the table), so now it is vertical and will give accurate alignment.
     
  9. outwest

    outwest Subscriber

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    I took the bottom of a plastic 35mm film can and put a short cheap Radio Shack laser in it. The dimple on the bottom of the can held the bottom of the laser and 3 nylon machine screws poked through the sides of the top of the can and bearing on the laser provided adjustment. Putting the can against a square on the floor and rotating it while making adjustments until the dot on the ceiling stayed put aligned it.
     
  10. pjbc

    pjbc Member

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    Greg Davis and outwest, tanks for the explanation..... it's 100% perpendicular in my mind! ;-)