Looking to Print a Caboose...

[cjp53]

finished model...

I would like one in N scale,very nice work.

[GimpLizard]

So the flat portion of the boards is actually 0.014" (not 0.020") wide?  I wonder if it would be better if you made the flat part of the boards 0.020"? I don't know how wide were the 1:1 boards.

Yes, correct. .014"

I'm not sure how wide the boards are either. But, like I mentioned, I counted approximately 90 boards. Which works out to 3.20" over 24 feet. 3.20/160 = .020

Hmmm. I jst got to thinkin'. (Which is always a bit risky...) I wonder of the pit-knickers would get upset if I went with 60 boards, rather than 90? That would make them .030" (scale 4.80") wide.

[peteski]

Yes, correct. .014"

I'm not sure how wide the boards are either. But, like I mentioned, I counted approximately 90 boards. Which works out to 3.20" over 24 feet. 3.20/160 = .020

Hmmm. I jst got to thinkin'. (Which is always a bit risky...) I wonder of the pit-knickers would get upset if I went with 60 boards, rather than 90? That would make them .030" (scale 4.80") wide.

This is where the "art" part of model design comes in.  Making a model look "right" sometimes involves straying from being 100% true to the prototype.

I don't have a MTL woooden caboose handy, but the boards on MTL 40' wooden reefers are about 0.030" wide.  They look "right" in my eyes.




The MTL 36' wooden reefer seem to have narrower boards.  They are about 0.020" wide.

[SkipGear]

.02" = 3.2"

Common tongue and groove boards are 3 11/16 so you are not far off. I think groove center to groove center should be 3 1/2".

[Maletrain]

When I scaled the boards off a picture, using the axle spacing of a truck for the scale, I got 3.23 scale inches.

When I measured the boards on a MicroTrains caboose,  I got 3.1 scale inches (to my eye averaged over 33 boards)

So, basically 0.020" in N scale.

Not so clear how to measure a groove in N scale.  To my eye, comparing a groove to a slightly separated caliper jaws spacing with a 10x loupe, that 0.006" looks substantailly too wide.  It looks more like 0.003" to me.  Considering that 0.006" is nearly an N scale inch, that seems too wide.  The 0.003" would still be nearly a half scale inch.

But wait, I took a picture of the caboose (crappy with my cell phone), and here it is:
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Using that and assuming the board grooves are 0.020" apart, I measure a groove to be 0.055".  Hard to know what is exactly a groove edge on that photo, because I am using light vs dark on a blurry blow-up of a grainy surface.  But I don't have the time to haul out and set up a macro lens and lights to get a better image.

That MicroTrains caboose is unpainted, so the finished painted product probably would have less-visible lines.

Scaling off Peteski's Rath reefer picture, and assuming those boards are 0.030" wide, those grooves look like 0.003" to me. And Peteski says they look about right to him.

So, I am thinking try to print some 0.020 spaced grooves in two widths, 0.006" and 0.003", spray both with a decently thin paint application, and post the pictures here for opinions.  That would probably become a go-to archive thread for the future.

[GimpLizard]

A .003 wide groove looks about right to me also. But I think Peteski makes a good point about a printer being able to reliably print that fine. I don't have a printer so I can't experiment. But I could make some "test" slabs, of different widths & groove spacings, and send them out for others to try. If anyone is interested let me know.

[Chris333]

Yes the real board gap makes no difference, you need to figure out what you'll be happy with after printing.

[Maletrain]

OK, with the sun up, I took some ambient light photos:

Here is the MicroTrains caboose with my dial caliper set to 0.100"
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Now those grooves seem to scale to 0.003 or even less. It depends on what part of the rounded edges you include in the definition of "groove."

I tried to post some pictures of the real thing, but they are too many bytes for inclusion.  [Strangely, I am having trouble editing them to lower resolution.  But, thanks to Windows 10, I see that all of the images from the camera card were uploaded to the "cloud", but I am not allowed access to them there.  Look for them in an advertising pop-up coming to you soon.]

Anyway, the real things appear to have less groove width than the unpainted MicroTrains caboose.

[Maletrain]

I have cropped some images of real B&O cabooses I took at the B&O Museum, so that they are less than 2 MB, but I cannot get even one of them to post to TRW.  Does anybody know why?  The image selections show in the attachment box, but when I hit post, the TRW shows a rotating circle for a moment, and then the screen for TRW inside the browser window goes white and just stays that way for tens of minutes, with the browser address bar reading https://www.therailwire.net/forum/index.php?action=post2;start=45;board=1  So I don't think it is an upload issue.  The picture I succeeded in posting did not do that.

[GimpLizard]

What file format are those pictures in?

[GimpLizard]

Here is the MicroTrains caboose with my dial caliper set to 0.010"

.010"? Looks more like .100". If it was set at .010, that would make the boards about .002" wide.

[Maletrain]

.010"? Looks more like .100". If it was set at .010, that would make the boards about .002" wide.

Yep, fixed it.  I retyped that post so many times due to the failures from the pictures not posting that I wasn't paying much attention to the typing and proof reading by the time it actually succeeded with the picture. 

[Sokramiketes]

Ted Culotta's presentation on making HO Scale masters covers the board width question:

http://speedwitchmedia.com/wp-content/uploads/2017/04/Scratchbuilding-PR-012020.pdf

Most boards in single sheathed cars are 5-1/4” wide, although 5-1/8” wide is common as well as 3-1/4"

5-1/4” is ~.060 in HO and .033 in N scale
5-1/8” is .058 and .032 in N scale
3-1/4” is .037 and .020 in N scale

Side sills are typically 9” channel or .100 in HO (.056 N)
In HO, .040x.100 for side sills and .040x.060 for sheathing boards
In N scale .020x.056 and .020x.030

Now, besides the different board widths, there were also flush boards and boards with a 45 degree chamfer... one appears to have larger gaps that the other.

So, two things... what was the prototype?  And what is the ratio of board gap you need (for printing) to actual board width?

Let's say the visible board gap is 1/2" on the prototype 5-1/4" car siding.  That's just under 10% of the side of the car should be board gap compared to board width.

So if you have to draw it at .005" for the board gap to render, then the visually appealing answer for a 5-1/4" board width is .05" to get the same effect.

That is quite a bit wider than prototype.  But hits the proportions.  In actuality I would first try splitting the distance and do boards around .035 or .040 and see what it looks like.

The infamous Rapido reefer board gaps looked so big because they didn't widen the boards to compensate for the board gaps they tooled. 

[Maletrain]

What file format are those pictures in?

All are .jpg.  The one that succeeded is 1,792 KB, and the ones that have not succeeded are 1, 653 KB and 1,927 KB.  All 3 files were taken with the same camera and downloaded from the same camera card to the same computer at the same time, even into the same folder on my computer.  Then they were each edited with the same program to crop them from jpg files that were over 5 MB to new jpg files that are the sizes stated above. 

I did have some problems with the first post that eventually succeeded with the MicroTrains caboose picture. but apparently because I initially tried to put all 3 photos in that post (among other "relearning experiences").  Once I got the post with the MicroTrains macro photo to work, I thought I had figured things out.  But, attempts to post both of the other pictures together failed, as did follow-on attempts to post them separately in their own posts. 

[Maletrain]

Ted Culotta's presentation on making HO Scale masters covers the board width question:

Now, besides the different board widths, there were also flush boards and boards with a 45 degree chamfer... one appears to have larger gaps that the other.

So, two things... what was the prototype?  And what is the ratio of board gap you need (for printing) to actual board width?

Let's say the visible board gap is 1/2" on the prototype 5-1/4" car siding.  That's just under 10% of the side of the car should be board gap compared to board width.

So if you have to draw it at .005" for the board gap to render, then the visually appealing answer for a 5-1/4" board width is .05" to get the same effect.

That is quite a bit wider than prototype.  But hits the proportions.  In actuality I would first try splitting the distance and do boards around .035 or .040 and see what it looks like.

The infamous Rapido reefer board gaps looked so big because they didn't widen the boards to compensate for the board gaps they tooled.

For this particular project, the grooves for the board spacing should be 0.020", which is 3.2" in N scale and certainly close enough to the 3.25" that Ted Culotta's presentation stated.  Drawings and pictures of the I-5 prototype support the 3.25" board apparent width. (Remember, it is tongue in groove, so its apparent width may vary slightly.)