Improving the Appearance of Stewart FT/F3/F7 Headlights


IronBeltKen

Lazy Daydreamer
I’ve had a small fleet of Stewart/Kato F7s since they came on the market in the mid-1990’s, and they are still among my favorite locos – they run smoother and pull more than any of my other engines of comparable size. However, there is one major shortcoming that can not be easily hidden - the headlight:

01_F7_4650_before_headlight_upgrade.jpg


If I ever wanted to shoot photos of these models to look “real”, that searchlight-sized headlight would be a dead giveaway. Since I don’t have the budget to go out and replace all the Stewarts with Genesis models, I had to do my own corrective surgery on them. This thread will describe the approach that finally worked for me after a few failed attempts.

The concept is actually quite simple: I just needed something to mask-out everything that does NOT look like a sealed twin-beam headlight. Since the lens used in Stewart body shells is cylindrical in shape, the mask would have to go directly in front of it – with an additional piece of clear sheet styrene to simulate the outer glass cover.

First, I needed to determine the correct size discs to cut out. The headlight lens diameter measured out at exactly 3/16ths of an inch; luckily, a local friend of mine had a collection of paper hole punchers of different diameters, including 3/16", which he kindly let me borrow. Starting with a sheet of Evergreen .040”-thick black sheet styrene, I drilled out several pairs of holes using a home-made template:

003_DrillingLensHoles.jpg


Once the light beam holes were drilled, all I needed to do was align them in the hole puncher and make the cut:

004_LiningUpThePuncher.jpg


…and that gave me perfectly-sized masking discs. I also took a sheet of Evergreen clear sheet styrene and punched-out a few “glass” covers as well:

006_LensFiltersAndGlassCovers.jpg


By recessing the front surface of the lens cylinder roughly 0.080” from the headlight opening, I was able to press-fit both the mask and the clear cover in front of it. But I ran into a problem when I tried to put the body shell back on the chassis: the rear of the headlight lens wasn't clearing the frame. I needed to cut some of it away [to the left of the red line]:

02_Headlight_lens_before_trimming.jpg


This introduced yet another problem: The back of the lens was no longer smooth as glass, but frosted - which might potentially dull the brightness of the LED:

04_Chopped_lens_frosty_surface.jpg


…luckily, a single drop of PlasticWeld was all I needed to restore the clear finish:

05_Chopped_lens_after_PlasticWeld_treatment.jpg


** HINT: Don’t try to cut away material from the FRONT end of the lens – I tried that and found that I could no longer fit it into the headlight cavity. Luckily I had a spare lens in my scrapbox!

My next step was to attach the mask to the front of the lens. This was important, because I would need to be able to twist the lens cylinder inside the headlight cavity in order to properly align the two light holes. I also had to avoid using too much cement, which could cause it to leak onto the outside surface of the lens cylinder or into the light holes. I used Testors Model Master plastic cement for this, since it would dry slowly enough for me fine-tune the position of the mask:

07_Lens_surface_dabbed_with_ModelMasters_cement.jpg


Since the prototype B&O F7s I was modeling had their headlight beams horizontally oriented, I lined up the light holes to form a "T" shape with the stem of the lens:

08_Mask_positioned_on_lens.jpg


I allowed 20 minutes for the cement to cure before re-inserting the lens in the body shell. Since the unmodified lens reaches all the way to the front of the headlight cavity, I had to avoid pushing it all the way back in if I wanted adequate space to fit in the mask and cover:

09_Lens_positioned_in_shell.jpg


As soon as I got the lens re-inserted, I was able to get the light holes aligned by gently nudging on the lens cylinder's stem. Once I was satisfied with the alignment, I placed a tiny dab of Testors cement to the lens inside the body so it wouldn’t be accidentally knocked out of alignment later on. I made sure to leave enough space for the glass cover:

11_Lens_with_mask_in_shell.jpg


To keep the outside [cut] surface of the glass cover from catching light and thereby being too visible, I traced over it with a black permanent marker. After allowing enough time for the cement inside the shell to cure, I pressed-on the clear styrene disk...

13_Glass_cover_applied.jpg


…and, voila: I now had a Stewart F-unit with a more believable-looking headlight!

14_F7_4650_with_new_headlight_mask.jpg


Also, the clear inside surfaces of the lens allow the smaller beams of light to still appear bright when viewed from a distance of 6 feet or more:

15_F7_4650_from_afar.jpg


If I want to get decent-looking photos, all I need to do now is apply some natural-looking scenery (e.g. trees, grass, and terrain) to the layout - a skill I have not yet mastered. That will be my New Years Resolution for 2017!
 
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A masterful piece of work Ken, you should have no problem with scenery once you put your mind to it. Only one observation.(Quote)I lined up the light holes to be perpendicular to the “stem” of the lens:(Quote). in actual fact they are at right angles to the perpendicular, a better description might be that they form a letter "T" configuration with the stem.
 
[There I go confirming my ignorance again!] Thanks Toot, I've made the correction...
 
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A masterful piece of work Ken, you should have no problem with scenery once you put your mind to it. Only one observation.(Quote)I lined up the light holes to be perpendicular to the “stem” of the lens:(Quote). in actual fact they are at right angles to the perpendicular, a better description might be that they form a letter "T" configuration with the stem.

By definition "perpendicular" means to be at right angles to a given line whether that line is vertical, horizontal or any angle in between. So he was correct in his first statement.
 
Ken- you did a great job of explaining your procedures and warned of possible problems
As one who has a habit of trying every wrong way to do something, I really appreciate the heads up. And the correct way to do it the first time!
Mikey
 
Ken- you did a great job of explaining your procedures and warned of possible problems
As one who has a habit of trying every wrong way to do something, I really appreciate the heads up. And the correct way to do it the first time!
Thanks Mikey, glad I was able to help!
 
Now that's modelling at its finest Ken!
You should seriously submit this for publication to MRH or MR!
 
Brilliant Ken, simply brilliant on so many levels.

We would be hard pressed to find a better "how to" article in any magazine.

This particular project is something I most likely will never attempt, but it was an interesting and enjoyable read, thank you Ken!
 
Now that's modelling at its finest Ken!
You should seriously submit this for publication to MRH or MR!

Thank you Rick! Of course if I were to do that, I'd have to use a my DSLR camera and shoot better-quality photos (these were all done from my cell phone).
 
Brilliant Ken, simply brilliant on so many levels.

We would be hard pressed to find a better "how to" article in any magazine.

This particular project is something I most likely will never attempt, but it was an interesting and enjoyable read, thank you Ken!

Thank you Louis, always appreciate your encouraging words!
 
Great! Having the right headlight can make all the difference, if you're a real fan of a certain time, or road.

Not sure who used to make brass or plastic headlight casing. I had a similar problem many years ago, regarding Stewart RS-3s for the Reading.
 



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