An N-Possible journal

[Mark5]

The upcoming locomotive boxes are a very similar design, albeit in a slightly more generic form. But the concept is the same, fills the pilot hole. They have top lid rather then a bottom lid, but I need to do it that way to accommodate Kato use cases with the same base box part.

Everyone will have a readily available option very soon!

Fantastic! 

[thumpernickle]

I have a lot of freight cars to convert and find that they don't have a dimple to help locate a mounting hole for body mounted couplers. What tips do any of you have for locating the correct location for the screw hole for body mounting these couplers? Some sort of jig? Careful measurements for each car? All of the above?

[Maletrain]

How about just holding the assembled coupler box of choice on the car in the position you want, then using a drill bit that closely but not tightly fits inside the mounting screw hole, to mark the car floor by hand turning the bit point against it.  Then remove the coupler box and you can see a center mark showing where to drill the proper sized hole (with a different sized bit, of course).

A set of numbered drill bits works well for this tactic, because they are in small diameter steps.  Eg: https://www.amazon.com/COMOWARE-Number-60pcs-Indexed-Storage/dp/B07RQKXS98/ref=sr_1_3_sspa  (I did not comparative shop, so there might be a better price elsewhere.)

[Jimbo]

I have a lot of freight cars to convert and find that they don't have a dimple to help locate a mounting hole for body mounted couplers. What tips do any of you have for locating the correct location for the screw hole for body mounting these couplers? Some sort of jig? Careful measurements for each car? All of the above?

I was planning to design some sort of locating jig for such.  I’m no expert at 3D design, but I think I’m skilled enough to handle something that simple.

When I do, I’ll post the design.  But it’s not a priority for me right now, given that most of my rolling stock HAS a dimple or hole to drill/locate the hole.

Jim

[Jimbo]

How about just holding the assembled coupler box of choice on the car in the position you want, then using a drill bit that closely but not tightly fits inside the mounting screw hole, to mark the car floor by hand turning the bit point against it.  Then remove the coupler box and you can see a center mark showing where to drill the proper sized hole (with a different sized bit, of course).

A set of numbered drill bits works well for this tactic, because they are in small diameter steps.  Eg: https://www.amazon.com/COMOWARE-Number-60pcs-Indexed-Storage/dp/B07RQKXS98/ref=sr_1_3_sspa  (I did not comparative shop, so there might be a better price elsewhere.)

I think the question was not about how to make the hole, but rather about the best way to locate the correct location for the hole.  I presume the poster is interested in ensuring that it isn’t off-center.  Even if only a little, off-center would likely create a big problem.

Having said that, I think your suggestion on HOW to make the dimple is an excellent one.

Jim

[Maletrain]

I am not seeing the problem with getting the box in the right place to use the drill bit dimpling technique.  It doesn't seem that hard (to me?) to get the box centered side-to-side and appropriately aligned with the end of the car.  Maybe I just have better eyesight? 

If eyesight is the problem, and alignment with a jig that depends on "feel" is desired, wouldn't that need to be full-width for the car and have the spotting hole set back from the end in a manner appropriate for the right "look" for a specific car?  It seems like you would need different gauges for each of the wide variety of cars being discussed in this thread.  Unless you have a lot of cars of the same type, that doesn't seem (to me) to be worth the trouble.

But, if you have a large lot of something to convert, then maybe a jig is in order. 

How about carefully measuring for the location on one car, drill the pilot hole in the car and also a flat piece of scrap wood or plastic.  Then put a pin in the hole in the car and place the flat piece with its hole on the car with that pin going through its hole.  Then carefully glue 3 strips of scrap wood or plastic to the flat piece so that they fit around the end and the sides of the car such that, with the pin removed, the flat piece can be positioned identically on other identical cars to serve as a jig for hole alignment.  Remember to make those holes the diameter of the pilot hole for the tap, not the clearance hole for the screw.

Or, people with 3D printers and CAD programs can make engineering projects for jigs.

[Jimbo]

I am not seeing the problem with getting the box in the right place to use the drill bit dimpling technique.  It doesn't seem that hard (to me?) to get the box centered side-to-side and appropriately aligned with the end of the car.  Maybe I just have better eyesight? 

If eyesight is the problem, and alignment with a jig that depends on "feel" is desired, wouldn't that need to be full-width for the car and have the spotting hole set back from the end in a manner appropriate for the right "look" for a specific car?  It seems like you would need different gauges for each of the wide variety of cars being discussed in this thread.  Unless you have a lot of cars of the same type, that doesn't seem (to me) to be worth the trouble.

But, if you have a large lot of something to convert, then maybe a jig is in order. 

How about carefully measuring for the location on one car, drill the pilot hole in the car and also a flat piece of scrap wood or plastic.  Then put a pin in the hole in the car and place the flat piece with its hole on the car with that pin going through its hole.  Then carefully glue 3 strips of scrap wood or plastic to the flat piece so that they fit around the end and the sides of the car such that, with the pin removed, the flat piece can be positioned identically on other identical cars to serve as a jig for hole alignment.  Remember to make those holes the diameter of the pilot hole for the tap, not the clearance hole for the screw.

Or, people with 3D printers and CAD programs can make engineering projects for jigs.

I agree with almost everything you said, except you and I disagree on whether it’s worth the trouble.  To me, it is… because I’m really skilled at screwing things up!   

In fact, I do have a 3D printer, which I plan to use to make fixtures such as this for (e.g.) Kato passenger cars.  I have enough of them to make it worthwhile.  I’m envisioning the fixture to look something like what you just described.

All of your ideas are great; I appreciate your thoughts.  And hopefully between us we’ve helped out @thumpernickle as well!

Jim

[Missaberoad]

Such a fixture was described and shared earlier in this very thread.

https://www.therailwire.net/forum/index.php?topic=59868.msg825192#msg825192

[thumpernickle]

Jimbo and Maletrain: I appreciate your comments.

I have tried the "eyeball" method and find that I am not always dead center with that method. As I need to convert 10-15 sets of the same type of freight car (like 12 Intermountain GS gondolas and another 7 Intermountain USRA gondolas), I was curious if anyone had developed any hints or tips on converting these.

And like Jimbo, I also have a fleet of passenger cars (KATO, Wheels of Time, Rapido, Railsmith, etc) to convert. I assume that perfectly centered coupler boxes are even more important on these longer cars.

I have some limited abilities to draw something up in TinkerCad and have access to a printer, so perhaps that is where I will turn to next.

Thanks for the ideas.

[GaryHinshaw]

I've found I can scribe centre-lines by eye with a #11 blade, such as on this example of starting a hole (ignore the filled hole):



Unless you're using proto:160 wheels, there is way more side-side play in the wheel/rail contact area than there is error in the coupler box placement.  It is inevitable that you will occasionally have to re-centre a car by hand to line the couplers up, but not very often.  (Same for the prototype.)  But by all means, make jigs if it helps you.

[Maletrain]

One other benefit of using a jig is that, if it is thick enough, it provides a true perpendicular alignment of the drill bit to the surface being drilled.  Assuming that you made the jig with perfectly perpendicular alignment, such as with a drill press.

That allows for simple hand drilling of the pilot holes in the models.  Assuming you are careful not to wallow-out the jig hole while doing repetitive hand drilling. 

[turbowhiz]

Honestly?  A belt sander?  How in the world...

One of these:

https://www.busybeetools.com/products/1in-belt-sander-craftex-cx-series

1” x 30” belt, use a fine grit belt. As silly as it sounds, I’ve found this tool to be remarkably useful for high precision work you might not assume it’s appropriate for. Like removing one row off one of these photoetched crossover platforms on a Prarie shadows 3800 car, which the platform is still installed on the model. Milling down bolsters as well.




Belt to table space is very tight; A typical freight car box cover for scale.



It was sort of an accidental discovery with respect to its utility, I didn’t seek it out originally, but it was lying around and its sure handy. I’ve used to mill down plastic coupler boxes in my earliest days of N scale experimentation.

Spend some time setting it up… Getting the table square and belt adjustments dialed in. Its not the be-all end all, but it is of real utility, and the cost of entry is low.

[turbowhiz]

Unless you're using proto:160 wheels, there is way more side-side play in the wheel/rail contact area than there is error in the coupler box placement.  It is inevitable that you will occasionally have to re-centre a car by hand to line the couplers up, but not very often.  (Same for the prototype.)  But by all means, make jigs if it helps you.

The closer to center you get the better; Fractions matter if you want the most optimal operating experience. Assuming the rest of the components are all in alignment, which isn't a given.

If you have tuned out the slop from in bolster, your wheelsets are properly in gauge and properly centered in the axle, your track gauge is not wide (looking at you Atlas C55, which can be very marginal at least in my experience) and the trucks themselves aren't sloppy (as in the axle fits the truck without sloppiness)  you will be able to make things very reliably couple without any interventions.

As part of my conversion process, I test coupling against the height gauge with the car pushed to the extremes in the gauge in both directions.. It should reliably couple on both extremes. And ideally it shouldn't move much at all... Two marginally sloppy cars still might not couple to each other if they are on opposite sides of the slop and but still pass the height gauge test. Now there is a great deal of sloppy stuff out there, and the amount of work to sort the issues can be vary a great deal depending on the model in question and how many of the problems it exhibits, but its certainly achievable. Now if the juice is worth the squeeze is a personal preference of course...

[Maletrain]

My experiences with other (than Npossible) couplers has been that alignment sloppiness is closer to the norm than precision is.  Even real Microtrains couplers, especially when mounted on trucks instead of car bodies, not infrequently still require some manual alignment to couple, even on straight track.

So, I am not going to worry about that for the Npossibles.

I have not yet had the time to convert a train to Npossible couplers for testing on my club's layout, where there is much trackwork in barely operable configurations.  I think the out-of-gauge, tilted, vertical angles, etc. there are the torture test that will tell me if Npossibles are a "go" for anywhere, or if they require more competent track work.

[vermonter_railfan]

Microtrains DODX 68' 40000 and 41000 series flat cars for M1 Abrams.

Long Shank Universal

Fairly straightforward conversion, honestly probably one of the easier conversions. This will work for both the red and green DODX flat cars that MTL ran. Simply just pop the coupler box top off, remove the original coupler, add the universal to the car and install the long shank coupler. Coupler height is great against the gauge on code 80 track.