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  1. #1
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    Aspheric owners help required

    I have had a go at turning my own acrylic aspheric lens, itís quite big at 32 MM diameter but so far it produces quite a good beam. But Iím not sure what to do with the back of the lens. I have just left it flat for now.

    My question for those who know more about aspheric lenses than I do is should the back be left flat or should it be convex or concave?
    Thanks in advance for any help.

    Aspheric owners help required-imag1121.jpg
    Aspheric owners help required-imag1124.jpg
    Aspheric owners help required-imag1125.jpg

  2. #2
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    I don't have squat for an answer, but that's looking really good for manual machining!

  3. #3
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    Flat for the win

    Ahortons are flat

    Saabluster on CPF amazing lights use flat based

    and I have some aspherics from Surplus shed with concave and convex bases and they are all poor compared to flat bottomed

    Cool but if turning and polishing there Yeti

  4. #4
    more carbon=more awesome
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    Flat back for sure.

    My turn:
    My bar lights running MTG-2s with no optics are okay, but I feel too much light is wasted, so I'm going to have a go at making some of these too. Do you reckon turning a lower profile pseudo-aspheric will work to give a floody beam? I can't really muck about with the depthing on these, so I'm thinking shallow convex at the front for the flood.
    Posting on the basis that ignorance shared is ignorance doubled.

  5. #5
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    damn, that's impressive, well done! You guys never cease to amaze me.

    BTW, I think I have that exact same chuck - direct mount screw on flat back, right?

  6. #6
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    Thanks for the help everyone, flat it will be then.

    Matt, it's easier to do than you would think especially when you have no real idea what shape it should be and you are doing it "freestyle".....any shape looks good. You'll never believe it started life as a flower vase from a junk shop. I just took a slug out of it with a hole saw.

    Yep screw on chuck.
    Aspheric owners help required-vase.jpg

  7. #7
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    how did you get the shape like that though? By setting the top slide angle in really small increments to shave of a bit at a time or by cutting a series of really narrow but increasing diameter circles?

    nice use of materials too, now you can wind people up by calling it a flower vase grade optic

  8. #8
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    Quote Originally Posted by mattthemuppet View Post
    how did you get the shape like that though? By setting the top slide angle in really small increments to shave of a bit at a time or by cutting a series of really narrow but increasing diameter circles?

    nice use of materials too, now you can wind people up by calling it a flower vase grade optic
    Nothing technical like that. I didn't have a compound/top slide fitted so just made the shape by turning the X and Y hand wheels at the same time.

    It's been finished off in the tiny Wizard lathe so now looks a bit better.

  9. #9
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    Thought that I would drag up this old thread to show that I did actually make this lens for a reason.

    Getting there slowly......
    Aspheric owners help required-010-800x450-.jpg
    Aspheric owners help required-002-800x450-.jpg
    Aspheric owners help required-001-800x450-.jpg
    Aspheric owners help required-004-800x450-.jpg

    Yes the LED is facing backwards. There will be one facing forward too. One for high and one for low.

    To be honest I took it for it's first ride tonight and it's a bit disappointing so will need more work but it sort of works....... just not as well as I had hoped
    Last edited by yetibetty; 02-19-2014 at 07:30 PM.

  10. #10
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    Well I did a bit more work on the lens and am now getting the result I was after. The low beam has a cut off at the top for the road.

    I only have one warm white XTE running @1A which I'm using for testing as it's all I have left, so only low beam at this time but it will be a lot brighter when I get the proper LEDs in.
    The rear facing LED fires into a forward facing reflector (see silly drawing)

    Aspheric owners help required-007-800x450-.jpg
    Aspheric owners help required-001-800x450-.jpg
    Aspheric owners help required-005-800x450-.jpg
    Aspheric owners help required-roadie-800x449-.jpg

  11. #11
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    Excellent! I've played with cut up reflectors trying to get a cut off type beam but was not pleased with the result. This is looking interesting.

  12. #12
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    ooh, that's a really neat idea. How did you work out the angle of the rear facing LED and reflector? Trial and error or that thing they call mathmatics? I'm guessing that the rear LED is individually switched and both on for high?

  13. #13
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    Quote Originally Posted by Vancbiker View Post
    Excellent! I've played with cut up reflectors trying to get a cut off type beam but was not pleased with the result. This is looking interesting.
    Thanks, I have tried all sorts over the years to get a road beam but none of them worked. Chopped up reflectors, making reflectors, apple pie dishes.... none of them worked. In the end I looked at car projector head lights and came up with a way to do away with the flap thing to get high and low.

  14. #14
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    Quote Originally Posted by mattthemuppet View Post
    ooh, that's a really neat idea. How did you work out the angle of the rear facing LED and reflector? Trial and error or that thing they call mathmatics? I'm guessing that the rear LED is individually switched and both on for high?
    A bit of both really. I made a test bed and just messed about with angles and stuff till it worked. You'll notice in one of the pics that the main body has a short slot and this is to allow some focus adjustment. So far so good as it's all going quite well.

    It will be left hand drive for the low beam as we drive on the left over here but I can't decide which of the two excepted beam patterns I prefer.

    Any thoughts on either of these?

    Aspheric owners help required-euro.jpgAspheric owners help required-british.jpg

  15. #15
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    I found an old XPG laying around so was able to test the high beam. It's raining again so just indoors but this thing is going to be nuts when it gets XMLs in.

    Makes the low beam look very yellow with the warm white LED
    Aspheric owners help required-low.jpg
    Aspheric owners help required-mentalone.jpg

    It projects everything including the solder pads
    Aspheric owners help required-mental.jpg

    Can't wait to get the new LEDs

  16. #16
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    Quote Originally Posted by yetibetty View Post
    Can't wait to get the new LEDs
    When do you want them by?

  17. #17
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    Now!

  18. #18
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    Can't do now, will tomorrow do instead?

  19. #19
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    Thanks for those OTH, If it was to ever stop raining I could go for a ride to test them out.

    It does look like a have a problem though. I don't think my strange design will ever allow me to get the high and low beams aligned with each other. Might end up as just the road beam with cut-off. I haven't given up yet but can't go riding in the rain with an open back light.

    Thanks again.

  20. #20
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    Let's hope you put those LEDs to better use than I did!

    Can't wait to see how it turns out.

  21. #21
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    Well, I have to admit that what was meant to be simple has turned out to be a real pain in the arse.

    I can get the low beam just how I want it with a razor sharp cut-off for either left or right hand drive and I can get the high beam just like a helicopter search light and switch from either with just a click of a remote switch that is right next to my thumb. But(why is there always a But)they donít align with each other.

    If I aim the light so that the low beam is just right then what happens when I hit high is that the high beam aims at the tops of trees. If I aim the light so that the high beam is just right then when I hit low, the low beam only lights the front tire. Sorry but I have to admit defeat on the idea of an all in one and decide what I want from this thing.

    It will be a road beam with cut-off for riding on the left and Iíll have to use a separate light for high. You canít win them all and I certainly didnít win this one.

    Still a good light for road use in traffic and a bit like driving a BMW so far as beams go.

    Iíll add some beam shots latter(for riding on the left).
    Last edited by yetibetty; 03-03-2014 at 06:09 PM.

  22. #22
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    I am all done with this light now and just have to make the screw on back. Shame I can't have the high beam incorporated into the same light but I'm happy with it and will add a small high beam pod to the side of this light.

    Beam shots are a bit strange as I couldn't take photos where it will actually be used as it's in very heavy traffic on the road so just found some darkish places for photos. The sky is very orange due to the tons of street lights around here.

    It's not the brightest thing in the world but it is great on the road.

    My front door!
    Aspheric owners help required-008.jpg

    Aspheric owners help required-012.jpg

    Aspheric owners help required-021.jpg

    The light without a yet to be made back
    Aspheric owners help required-010.jpg

    What's behind the lens
    Aspheric owners help required-004-1024x576-.jpg

    This could possibly be my last DIY light as I only needed a road light to complete my set.

    Once again thanks to Over The Hill for the XML.

  23. #23
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    What's interesting is now that you have shaped the mask you can see what effect it has on the beam pattern.

    I know you have put a lot of thought and effort in to this light. Hopefully it will inspire others to do something similar so that road lights will move forwards from just having more lumens to dazzle oncoming drivers to actually putting them somewhere that benefits us.

    Top job mate.

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