Author Topic: MV lenses?  (Read 1196 times)

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peteski

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Re: MV lenses?
« Reply #15 on: March 11, 2019, 04:11:56 PM »
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Bob, all the lights you show are larger headlights. There you can drill a hole large enough for enough light to shine through (using fiber optic or whatever).  But that trick will be a bit tougher if trying to light up one of the dual headlight units used in more modern diesels. Those headlights are quite a bit smaller.  Like I said, one can try drilling a #80 hole, and use 0.010" optical fiber, but will that produce enough light to be viable?  With the advent of bright white LEDs, I like my headlights bright enough to illuminate the track in front of the locomotive.  :)
« Last Edit: March 11, 2019, 10:26:23 PM by peteski »
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central.vermont

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Re: MV lenses?
« Reply #16 on: March 11, 2019, 10:09:48 PM »
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Bob, are your models HO or N?
 Joe D

Those are N Joe!!!!  :o :o :o

Jon

robert3985

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Re: MV lenses?
« Reply #17 on: March 12, 2019, 12:38:19 AM »
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Bob, are your models HO or N?
 Joe D

@Joetrain59  Joe, yup...as has been emphatically stated by @central.vermont , they are N-scale.

It's kinda difficult to tell without seeing a big-ole Microtrains coupler with its dongle hanging down... :)

Thanks very much for the compliment!

Cheerio!
Bob Gilmore

robert3985

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Re: MV lenses?
« Reply #18 on: March 12, 2019, 12:58:18 AM »
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Bob, all the lights you show are larger headlights. There you can drill a hole large enough for enough light to shine through (using fiber optic or whatever).  But that trick will be a bit tougher if trying to light up one of the dual headlight units used in more modern diesels. Those headlights are quite a bit smaller.  Like I said, one can try drilling a #80 hole, and use 0.010" optical fiber, but will that produce enough light to be viable?  With the advent of bright white LEDs, I like my headlights bright enough to illuminate the track in front of the locomotive.  :)

@petski Peter, Unfortunately, I didn't have any photos of my brass modern diesels I put the drilled MV lenses in, 'cause I sold all of 'em several years ago.  Since I didn't have DCC at the time, I used a single 1.3V incandescent bulb hooked up to a diode matrix for constant lighting and it was plenty bright and exactly the right color.  I melted the ends of two appropriate diameter fiber optic strands together where my incandescent light was, with a thin aluminum foil light shield (and heat sink) on top and bottom of the light...the melted-together fiber optic strands entering the light shield and being crimped so that very little light leaks out.  I was doing brass models, so I had more room than plastic diesels, but using a properly colored bright LED, I am sure that not having enough light is not going to be a problem.

With the room lights out, the MV lens/fiber optic setup would cast a really great looking "beam" on the track, with sharp shadows on the layout room walls that were huge.  Me and the kids really enjoyed the effect, but I never operated the layout in the dark...just fooled around with the lights.

To represent lit headlights in daylight, the MV lens/ fiber optic setup did the job perfectly IMHO with my incandescent bulb as the light source.  I don't know why using an LED would change that prescription.

Cheerio!
Bob Gilmore

peteski

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Re: MV lenses?
« Reply #19 on: March 12, 2019, 01:20:07 AM »
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Bob, I guess the unanswered question here is what was the diameter of the hole you drilled and of the fiber optic you used.
If those were diesel locos with dual-beam headlights, then you likely had to use the smallest MV lenses available (which were the same size as the marker lights you use on that caboose).

I do some miniature work myself, and often work with plastic fiber optics, but I have a hard time imagining a small diameter fiber optic strand emitting enough light to "cast a really great looking "beam" on the track, with sharp shadows on the layout room walls that were huge".   Really?  All that light from a tiny 1.3V bulb shining just a small fraction of its already-minuscule light output though a tiny fiber optic?
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robert3985

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Re: MV lenses?
« Reply #20 on: March 12, 2019, 05:03:44 AM »
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Bob, I guess the unanswered question here is what was the diameter of the hole you drilled and of the fiber optic you used.
If those were diesel locos with dual-beam headlights, then you likely had to use the smallest MV lenses available (which were the same size as the marker lights you use on that caboose).

I do some miniature work myself, and often work with plastic fiber optics, but I have a hard time imagining a small diameter fiber optic strand emitting enough light to "cast a really great looking "beam" on the track, with sharp shadows on the layout room walls that were huge".   Really?  All that light from a tiny 1.3V bulb shining just a small fraction of its already-minuscule light output though a tiny fiber optic?

I don't have my workbench up.  My modern engines are sold.  My materials are somewhere (I think).  I did this over a decade ago.  It's not exactly technical, and yes Peter..."Really"

Just because the small bulbs I have are tiny does not mean their output is tiny.  I would suppose that a light source for the same thing today would be a high-output LED...so what I used is beside the point.   Doesn't cost much to try it out...and yes, the shadows of the passing buildings, trees and signal bridges on the wall were "huge".  I don't have to imagine it, since it was a significant experience for me and my kids because it was so cool.

If ya don't believe me...tough.  I did it, and I lived it.  Try it yourself to prove me wrong...then you'll have more than merely your assumptions.  AND...what possible reason would I have to mislead anyone here??????   HUH???  :trollface:

My first efforts were to form a lens by melting the fiber optic strand over an alcohol flame until it was the right size to cover the hole in the light housing.  I didn't like the omni-directional quality of the light...the beams from the top and bottom lenses were going to different places and you could see it with your naked eye in a room with normal lighting.  It was much easier to get the MV lenses pointed in somewhat the same direction...but the quantity of light was never an issue, as the subminiature bulbs were very bright, and also long-lasting...I never had one burn out.

Here's a photo of my brass Centennials with just the fiber-optic strand melted lenses in the headlight holes.  Brightness isn't the problem here, it's that the beams are not going in the same direction as you can see because the top light is much brighter than the bottom light in this photo...but PLENTY BRIGHT...

Photo (1) - Overland Models Centennials with fiber-optic lenses in the headlights, illuminated with my 1.3V subminiature incandescent cylindrical light-bulb:


Photo (2) - Overland Models Centennial with fiber-optic lenses in the headlight, no power:


Needless to say, with the lights off, plain old MV lenses without being drilled out and lit look much better.  But, there's PLENTY of light, as the photo clearly shows.

Cheerio!
Bob Gilmore

peteski

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Re: MV lenses?
« Reply #21 on: March 12, 2019, 05:39:16 AM »
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Well Bob, now you're showing me models with no MV lenses, but just a much thicker mushroomed fiber optic. That I can easily believe will emit the amount of light needed to create shadows in a very dark room.  And you don't recall the diameter of the fibers you used in the MV-Lens/hole install?  Oh well.

I guess there is no need to keep this going. My mind won't change (and I'm not about to run my own test - way too many projects ion my bench already).
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johnb

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Re: MV lenses?
« Reply #22 on: March 12, 2019, 08:56:12 AM »
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Bob, I guess the unanswered question here is what was the diameter of the hole you drilled and of the fiber optic you used.
If those were diesel locos with dual-beam headlights, then you likely had to use the smallest MV lenses available (which were the same size as the marker lights you use on that caboose).

I do some miniature work myself, and often work with plastic fiber optics, but I have a hard time imagining a small diameter fiber optic strand emitting enough light to "cast a really great looking "beam" on the track, with sharp shadows on the layout room walls that were huge".   Really?  All that light from a tiny 1.3V bulb shining just a small fraction of its already-minuscule light output though a tiny fiber optic?
about 8 years ago when I was just getting back into active modeling, I added MV Lenses and NSN details to this Kato U30C, I did not light them.

SP-Wolf

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Re: MV lenses?
« Reply #23 on: March 12, 2019, 10:21:21 AM »
+3
I don't use MV lenses -- I went straight for fiber optic.
I use .030 and .020 -



Thanks,
Wolf

robert3985

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Re: MV lenses?
« Reply #24 on: March 12, 2019, 11:08:37 AM »
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Well Bob, now you're showing me models with no MV lenses, but just a much thicker mushroomed fiber optic. That I can easily believe will emit the amount of light needed to create shadows in a very dark room.  And you don't recall the diameter of the fibers you used in the MV-Lens/hole install?  Oh well.

I guess there is no need to keep this going. My mind won't change (and I'm not about to run my own test - way too many projects ion my bench already).

Well Peter, I find it interesting that you assume the fiber optic strand I used for the mushroomed ends, was "much thicker"....since nowhere in what I wrote did I state that.  I used the same fiber optic strands in all of my MV lens light installs, as well as my non-MV lens light installs.  I only have one size on hand because it works for both larger N-scale headlights and small ones.

As for shadows on the wall, they're there...even if your mind hasn't been changed, which makes your opinion totally irrelevant to the facts.  :trollface:

Cheerio!
Bob Gilmore

peteski

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Re: MV lenses?
« Reply #25 on: March 12, 2019, 03:10:12 PM »
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Well Peter, I find it interesting that you assume the fiber optic strand I used for the mushroomed ends, was "much thicker"....since nowhere in what I wrote did I state that.  I used the same fiber optic strands in all of my MV lens light installs, as well as my non-MV lens light installs.  I only have one size on hand because it works for both larger N-scale headlights and small ones.

As for shadows on the wall, they're there...even if your mind hasn't been changed, which makes your opinion totally irrelevant to the facts.  :trollface:

Cheerio!
Bob Gilmore

Bob, we are now getting into a pissin' contest.  The photos and descriptions in you previous post indicate that on those particular models you just used fiber optics (mushroomed) without the MV lens.  The photo shows that the mushroomed fiber fills the entire headlight opening. 

I guess the misunderstanding is due to me thinking that when you were using a fiber optics with the MV lenses, the fiber (and the hole drilled in the lens) was much smaller in diameter than the lens itself (so a large part of that mirrored reflector was still there, and a very thin optical fiber was inserted into that hole.   If that was the case then the optical fibers would have to been much smaller diameter than the lens (and than the headlight opening in the shell).   But I think that now I'm beginning to see the error in my thinking. 

Let me see if I now I understand your installs:  You did drill a small hole in the MV lens, then you places a fiber optic (of a  diameter about the same as the MV lens) and placed it right against the mirrored part of the MV lens and the hole drilled in it.  So the light coming from the end of the optical fiber would mostly shine against the mirrored back, with some small amount passing through the hole, and then out of the MV lens.  Did I get that right?
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robert3985

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Re: MV lenses?
« Reply #26 on: March 13, 2019, 04:26:10 PM »
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Bob, we are now getting into a pissin' contest.  The photos and descriptions in you previous post indicate that on those particular models you just used fiber optics (mushroomed) without the MV lens.  The photo shows that the mushroomed fiber fills the entire headlight opening. 

I guess the misunderstanding is due to me thinking that when you were using a fiber optics with the MV lenses, the fiber (and the hole drilled in the lens) was much smaller in diameter than the lens itself (so a large part of that mirrored reflector was still there, and a very thin optical fiber was inserted into that hole.   If that was the case then the optical fibers would have to been much smaller diameter than the lens (and than the headlight opening in the shell).   But I think that now I'm beginning to see the error in my thinking. 

Let me see if I now I understand your installs:  You did drill a small hole in the MV lens, then you places a fiber optic (of a  diameter about the same as the MV lens) and placed it right against the mirrored part of the MV lens and the hole drilled in it.  So the light coming from the end of the optical fiber would mostly shine against the mirrored back, with some small amount passing through the hole, and then out of the MV lens.  Did I get that right?

I don't think it's a "pissin'" contest.  The problem is twofold (1) You are making assumptions that have no evidence in anything I've written, and (2) I am not providing exact details...aka "measurements" of my drilling and fiber optic installs.

Naturally, you are going to harvest your own experiences to draw conclusions, but...in this case...your experiences are not my experiences.

So, putting away the "pissin'" contest accusation,  here are some finer details about what I did, and I'm even going to provide at least two measurements.  Maybe they'll help clear things up.

Since the viability of larger MV lens/fiber optic installs is not in question, and since I'm using the same fiber optic strand diameter in ALL of my headlights, I'll say that in my case, the diameter of the fiber optic wasn't a factor in the success of the install.  I also used the same light source and electronics to get the voltage to the bulb from DC rails to be both directional (the light goes off when the engine goes backwards) and the lighting is constant ( the light comes on after cranking up the throttle a bit...before the engine starts to move...most of the time).

The diameter of the fiber optic strand I used was .020"

The diameter of the MV lens I used was their smallest, which is .046", or in some instances their second smallest which is .052"

I used a tool steel center punch made from a round bar of tool steel, ground to a sharp point to make the divot in the aluminum back and acts as a "start" for drilling...centering the point if the tool by grinding the punch while spinning in my lathe.

I held the MV lenses in my lathe's 3-jaw self-centering chuck, with a backing plate made from a birch dowel that had been turned to the same diameter as the MV lens.  This allowed the wood dowel to compress slightly, and the jaws to hold the MV lens tightly without distorting it very much, or making the aluminum reflector pop off.

I chucked the round tool steel punch in my lathe's tailstock chuck and ran it in so that it punched a divot exactly in the center of the backside of the MV lens...but gently and just enough so that my drill bit wouldn't wander.

I then drilled a .020" hole in the back of the MV lens by turning my lathe on, then running the tailstock in with a fresh #76 bit chucked in the tailstock's chuck so the hole intruded halfway into the dome of the MV lens.

I then cut the tip of a piece of my .020" diameter fiber optic strand with my NWSL Chopper to get a clean cut on the end

Next, I slightly melted the tip, so that the flat tip of the fiber optic goes slightly domed and clear using my laboratory alcohol burner...I want a relatively cool flame for added control.

Then, I check to make sure the newly domed fiber optic strand fits in the hole I've drilled in back of the MV lens...and if it's slightly too big, I'll mic it and enlarge the hole slightly using a pin-vice and an appropriately sized bit so that it's a precision fit...not tight, but not flopping around either.  If it's more than "slightly" too big, I'll do the melting step again to get it right.

I cement the fiber optic into the hole by coating it with clear 5 minute epoxy and inserting it into the hole until the dome of the slightly melted fiber optic strand bottoms out on the bottom of the hole.

The .020" fiber optic strand should stand relatively straight up from the back of the MV lens if the hole is drilled properly...if it isn't, then straighten it before the epoxy cures.

After I epoxied the lenses into the holes in the headlights and let it cure, I located where my light source was going to be, trimmed the two strands of fiber optic so that they were nearly the same length, held them with some tweezers so they were touching, and melted that end into a blob...and let it cool.

Those are the important parts of how I did, and will continue to do my MV lens headlights with fiber optic "bulbs" in them.

Cheerio!
Bob Gilmore

peteski

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Re: MV lenses?
« Reply #27 on: March 14, 2019, 01:24:23 AM »
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Thanks for the very thorough explanation Bob. You are correct, you only provided partial info and I was, filling in the unknowns from my own experience.  It's now all perfectly clear!

So if you took a 0.046" MV lens (which BTW, would be 7.4" in 1:1 loco, which is close in size for those more modern sealed-beam headlights), and drilled a 0.020" hole in the middle, the reflector ends up being just a ring, 0.013" wide.  Not much of a reflector.  I guess I would have to duplicate what you did, and judge it for myself if it would be worth the trouble of trying to make the headlight look realistic with the light shut off.

And if you use the 0.020" fiber without the MV lens, then you must be mushrooming it out to around 0.040 to fill the headlight opening, correct?
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robert3985

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Re: MV lenses?
« Reply #28 on: March 14, 2019, 01:39:04 PM »
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Thanks for the very thorough explanation Bob. You are correct, you only provided partial info and I was, filling in the unknowns from my own experience.  It's now all perfectly clear!

So if you took a 0.046" MV lens (which BTW, would be 7.4" in 1:1 loco, which is close in size for those more modern sealed-beam headlights), and drilled a 0.020" hole in the middle, the reflector ends up being just a ring, 0.013" wide.  Not much of a reflector.  I guess I would have to duplicate what you did, and judge it for myself if it would be worth the trouble of trying to make the headlight look realistic with the light shut off.

And if you use the 0.020" fiber without the MV lens, then you must be mushrooming it out to around 0.040 to fill the headlight opening, correct?

Peter, I mushroomed them so they would be an interference fit...whatever that measurement was/is.  The size of the headlight holes in both plastic and brass locomotives is not uniform, and the sizes of the brass castings and the cast-on plastic headlights also differ from model to model.  Sometimes, the headlight casting is so small, there's no way a scale-sized headlight reflector will fit INSIDE the model headlight's cylinders that represent the outside of the sealed beam housings.  I've found that if I taper the front surface of these with a larger, sharp drill bit...the curved backside of the MV lens will nestle down pretty good into this, even if the lens won't actually insert inside the tube...and this looks pretty good.  The same with the mushroomed fiber optic strands.  If the front edges of the headlight's housing cylinders are left "square"...both the MV lenses and the mushroomed fiber optic fiber noticeably protrude in front of the housing with a space between their backs and the front of the model's headlight housing.

Because of the much narrower band of reflector aluminum left on the small MV lenses rear after drilling as opposed to steam engine headlights, it was especially important to get the hole centered, which is the main reason I used my lathe to do the drilling, since the hole being off-center would be extremely evident with the narrow reflector material exacerbating any off-centeredness.    Also, since I have the tools....why not use 'em???

I also found that sometimes, maybe 25% of the time, the aluminum backing material would come off if I took the drilling too fast.  The secret was to drill only a few mils, then back the bit out and clean it off, then drill a few more mils...repeating the process until I was completely through the metal backing and into the clear plastic.  I never had the metal backing come off after drilling the lenses this way, but sharp bits are essential.

Now...maybe a smaller diameter fiber optic strand would work just as well to conduct light, but be better looking because there would be more reflector left in the MV lens.  I never tried it, but I can see the possibility of that being the case.  I think a smaller hole would also make the loosening of the metal backing on the MV lenses less likely too.

Cheerio!
Bob Gilmore

peteski

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Re: MV lenses?
« Reply #29 on: March 14, 2019, 05:30:55 PM »
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Again, thanks for the thorough explanation!
--- Peteski de Snarkski
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