Nn3

[Lemosteam]

Before hulk smashing it, why not try to resin cast it as a master using a 50/50 mix of resin and tungsten powder?

@cbroughton67 had great success casting F22 flats using this method.

[Chris333]

The domes are filled with Tungsten discs. The smokebox has a Cerrobend weight in it. The tank all around the motor has a Cerrobend weight in it. The roof of the cab also has Cerrobend. They were made with printed molds. I don't think weight is the problem. It is the pickups.




There are Z gauge trucks with Kato style pick-ups, but their wheelbase is too long.


The whole locomotive is less than 2" long.

[peteski]

Or have the shell printed in brass.  That would add some heft to the model.

In the recent "The Short & Nn3arrow" column in N scale Mag. Tom Knapp mentioned having his 3D shells rendered in brass.  From what the photos show, those are really nice castings.  I have no idea how much those cost, but Tom's email address is thomasknapp@att.net and he welcomes comments and questions from other modelers. Here's an excerpt from that article:



EDIT:   Have you verified that each wheelset reliably picks up  power?

[Chris333]

Tom has posted exactly what those cost from 2 different places on the Nn3 list. On place overseas you just send the file and is expensive. I think it was around $200. The other you print the model in a special burn out resin and then send that model to be cast in brass.

I think this #11 blade will help describe my problem.

[Chris333]

So this whole Nn3 thing started...  A guy on FB printed out my HOn30 Climax https://www.printables.com/model/528961-hon30-climax  the print looked good and he asked about the chassis I used. I didn't use a chassis, I made one for it. The guy gave up after that. But the same day I opened the file on my computer and just for fun I printed it in N scale. Then I spent some time modifying the file to better suit N scale, like making the walls thicker. Then I took my drawings of Climax A313 (currently being restored) and changed them to N scale. I copied Randy's chassis (or I thought) to get it running. Later changed the chassis to better match Randy's. 100's of prints later I had this:

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These photos are a few months old now.

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[Chris333]

I just checked. Tom had a SP #18 loco done in brass by Sculpteo in France for $106 and said the same loco by Trackside Details in CA would be about $20.  https://www.tracksidedetails.com/tmVBandB.php

I need to try one of them out, but I do hate drilling .010" holes into thick brass 

[garethashenden]

This is why we can't have nice things nice things take so long...

Playing around on the screen for a better way to route the pick-ups.



On "paper" those .015" strips hang down .002" into the axle slot.

And I'm still not done because even though the wire fit perfectly in place. I am now printing a new chassis block that will let the strip snap into place. Never ending. At least I have a body I'm happy with 

Consider adding a pickup skate. The best modeler I know uses them on small engines and it makes a world of difference. They're hard to see too.
Take a piece of phosphor bronze strip, cut short enough to fit between the wheels at rail level. Bend up the ends at a 45°ish angle. Solder a piece of wire to the inside of the skate and to your pickup strip. Tweak the angle of the wire so that the skate slides along the rail with gentle pressure. This should make your engine more reliable. It doesn't have to be PB, but that's the best if you've got it. About 0.010" thick.

[Chris333]

A brass HOn30 Forney come with those under the ashpan.  https://resourcedrails.com/products/hon30-brass-train-trooper-sandy-river-rangeley-lakes-24-2-6-2-fp-copy

[garethashenden]

Exactly like that. I was trying to find a picture to illustrate and that will do nicely!

[Sokramiketes]

Chris, don't you need to spring, or otherwise equalize, at least the center driver? 

You have the pickup strip running across the top.  Can that hit coupler springs that are in the top of each axle cavity?

Or, less fancy, widen the channel for the pick up strips, allowing the whole mess to float up and down a bit, with some pre-load bent into it downward. 

[chessie system fan]

I feel like Mike is right. Turning the wire into a leaf spring of some sort seems like a good idea.  You might need to split the wire into sections to make it work. Would a trimmed  Atlas/Kato pickup strip be a better starting point? Or maybe the metal strip "spring" on the rear of Kato rapido-equiped coupler pockets?

[timwatson]

I have an idea that builds off of some findings I have experienced. Keep the design you have but move the large wire away from the wheels. It’s obviously adding too much friction. Move the large wire away from its current spot and then use .008” phosphor bronze “feeders” down to each wheel. These will have very little impact on adding friction to the mechanism and will give you more pickup points to the wheels.

I have used this same small .008” wire approach on the Brookville loco mech I previously made. The .010” wire is pictured but in my tests it added far too much friction to the mechanism so it’s an example of what not to use. It’s in the picture featured with the exacto knife.
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I drew up what I mean to help illustrate. You’ll make a tiny vertical channel under the main large wire channel and thread the .008” PB wire under the larger wire and then solder tack it. I have done the same basic idea but with an N scale pcb board tie, so it should work. My pcb tie would be sitting in for your .015” wire and turned 90 degrees but it’s the same concept. Let me know how it goes.
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[timwatson]

Unsure why it quoted my post but “bump”? 

[Chris333]

Well whatever I do to the 0-6-0T, it won't be for a while. I have rebuilt the chassis about 6 times back into a running loco after each change I'd made. I need a rest.

In the meantime I will continue to come up with wacky ideas. This is all based off of a Showcase Miniatures Nn3 Climax kit. Theirs was a little bit too big and modern for me. So I printed a frame, tank, cab, and boiler. Not all the detail yet, but just to see what it looks like.

[Chris333]

OK just spit balling on the 0-6-0T chassis...   I was looking at some photos. On the N gauge model the frame side walls are thick enough to thread screws for the pickups into. When I narrow the frame down to Z gauge the frame is too thin.

There are 3 worms on the shaft that drive each wheel. Do I need the center worm? Without it I can make the frame thicker in the center only where the screws need to go.