Seeking advice on custom brass bending.

[Lemosteam]

3d printed.  .003 is easier than 0.005.  That hat section looks more like this to me:

__         __
   \____/         This will be easier to form.

Rather than this

__        __   
   |____|

I will share some designs tomorrow.  I cannot promise rivets unless you etch first and then bend.

[Andrew Hutchinson]

I'd stamp it. If you want to play around try some .0015 in a soldered together die. Styrene even works sometimes. .005" brass can be difficult to form as tightly as you want with the relatively light pressure you'll be generating. To get it sharp you'll really need to make it flow. .003" thick and less brass shim stock works well for a lot of N scale items. If you're worried about registration either cut it out after the fact or make registration holes outside if the usable piece. The article Skibbe was referring to was by a Robert whose last name I can't remember (last name might start with a "C") and it was in a very early edition of N scale or similar Mainline Modeler circa 1989-91.If memory serves the guy made some nice stanchions for an SD40something.

Andrew Hutchinson

[Lemosteam]

@SandyEggoJake  Initial design:
Flat blank:


Formed:


@Andrew Hutchinson is correct alignment is crucial.  the strip starts out at 2mm wide.  Can you buy that in .003 thick material?  0.55mm alignment holes in each end are required. 

I think you will have to make an etching of the strips with thru etching for the holes and half etching except at the rivet locations starting with .006 material.

I made the upper die thick so it could be whacked with a hammer and a small block of wood.  That may be the only way to get the material to flow as Andrew suggests.

[SandyEggoJake]

Thanks!  I think that would work.  And a much easier die than I was thinking for a pinch roller. 

@Andrew Hutchinson , why do you suggest to use a pair of 0.0015" brass stock, soldered, rather than the 0.003" sheet from K&S, which seems to have adequate rigidity?  The soldered pair would likely be much harder than the 0.003 brass, but too me, getting two sheets soldered and be the right thickness seems an extra step without value?  What am I missing?

And for reference, instead of posts, I suspect it might also work with replaceable guide pins.  That way, instead of PE, one might simply drill the reference holes in the stock , perhaps using a pin-less top die, flipped over?

And might be able to create a post formation top die (really just a piece of channel with reference holes) that fits over the part and lower die and acts as a guide to score/trim the part to final width. 

Not sure etching rivets prior to channel formation would be ideal.  With this thin stock, I suspect pounding on the die would then obscure this detail.   For rivets, after hat channel formation, I might be able to use the same die to install them.  Perhaps inserting a metal strip with the rivet pattern and reference posts in the top channel.  And then placing a strip of styrene padding on the lower die to keep it from rebending the channel, then tapping away with the hammer. 

Now to just make or have it made....

 

[Lemosteam]

@SandyEggoJake I can make these designs and any others you want available on Shapeways.  You could actually get the dies made from stainless steel there.  Might be kinda expensive, but it would handle as many as you wanted to make.

I can make a separate set to fixture the drilled holes for the strip and another top die that could be used to trim the flanges.

You did not specify whether the dimensions were to the inside of the channel or the outside, but I can make instant adjustments to the rib model and the dieset  will adjust to the new dimensions automatically.

Obviously this would all be done at your risk and confidence, but I am glad to make the designs for you.

[SandyEggoJake]

Thx for the offer, John.  I think for several reasons, I'll forgo 3DP for the dies.  Instead of reference posts, I've sourced a place that can provide replaceable tapered locating pins in polished tool steel, with a head of just 0.5mm by 5 mm, which without posts, greatly simplifies the rest of the die set.  Once I have some in hand, I plan to use them to spec out the tool path for the rest of the die set. 

But pls save your file!  If such works, I might then come back to you to have you use it to create via 3DP ss various sub 0.5 mm x 0.7mm rivet punch plates with the same reference holes, which could be inserted into the groove of the upper die as needed.   Stay tuned... understanding that this is a low burn project.

[peteski]

I still think that photoetching the rivets in brass blanks before forming them into the hat-shape would produce much more realistic looking and closer to scale rivets.

[u18b]

Does anyone remember an article way back when, where someone was forming locomotive stanchions out of .002-.003" brass sheet stock?  Supposedly they were fairly sturdy once formed, and was something I always wanted to try.

For what you are doing, and the thin materials involved, I think all you need is a stamping form... not a roller or bender.  Just smash the sheet between two forms.

Yep.  I remember that.  Wow.  That was a good while ago.

That goes back to early days of N-Scale mag or maybe even the N-Trak newsletter.
That was something like late 80s or early 90s.

Definitely before Gold Medal Models stuff.

[Cajonpassfan]

In the 1931 Car Builders Cyc, p120, shows fig 24 for a Bx-3.  This drawing has dimension of the hat channels; cross section as 7.5" wide, 3" depth, hat width (w/o brim) of 5", and using 1/4" stock.  So each brim width would be 1.5".

1/4" stock scaled to N would be 0.0015".  Flimsy even with added rigidity of the shape and solder. 

So I suspect I will want to double that to 0.003" brass stock.
Such would allow me to use the following dimensions:

Nominal in mm:
width: 1.2 mm
depth: ~0.5
width of hat w/o brim: ~.75 mm
width of brim: .25 mm

Sure, small, but definitely a noticeable feature.

Late to this post Jake, but I too have wondered how to do this in the past, for both the boxcars, and the stock cars.
If you can figure out a way to stamp a true "hat" shape, more power to you, but a.25mm "brim" flange, formed at 90 degree angles (see drawing below) will be tough if not impossible, imho. For the box/furniture cars at least, I was going to use two L shapes and a flat strip inbetween, with a rivet row running down the middle, even though I know the L portion was asymmetrical. Including pics for our non-slobbering, non-SF friends...
Otto

[Andrew Hutchinson]

Sorry, what I meant was a single .0015" used as is rather than two pieces soldered together. I get it in rolls. The type of die Lemosteam posted is what I usually use, either in a vise or in an arbor press.

PS it was Robert Culver who wrote the stanchion stamping article.

Andrew Hutchinson

[SandyEggoJake]

25mm "brim" flange, formed at 90 degree angles (see drawing below) will be tough if not impossible

It's the technical challenge of this part that has captured my interest... if it can be done, it opens a door in N to some of the most common cars of the Santa Fe in the first half of the 20th century.  And I love the pics, Otto!

Here is my all time fav of an AT&SF car with these iconic hat channels....  in this case, an Fe-P car. 



Spring of 1927...with Lindbergh's wing coming out of Ryan's shop in downtown San Diego.    Layering on some more AT&SF slobber, she's got andrews trucks, door & a half, and fishbelly center sill but also extra height with a 7/5/5/ murphy end. 

[Cajonpassfan]

What were those guys thinking
Great shot Jake!
Otto

[SandyEggoJake]

My guess is "why the $%^& did we build the wing on the second floor"? 

Its actually from a cool series of action pics, which follows with :

https://www.flickr.com/photos/sdasmarchives/6057245492/in/photolist-6i1CAa-oFMeHN-hzQERF-aedapg-aefY47-bT2keD-eJWui6-5YrQiH-qx2EdN-mkYnKx-p4FxgC-aEqMP9-6i1D3K-6i1bwV-67YMnk-aedast-o1tS27-8rvhaR-8tts5x-nWyQJa-7VRvGo-nCiT5p-aefY6A-gkgPpR-qx3TZo-4GrtSH-pkgYC3-7Pu69S-8Az34b-56LgDA-iCXDj3-pj9x9m-pkUnNZ-apsNuV-2MBBUn-9NHGz3-5nuou9-5nq7RD-a2rDcX-9iMtwo-6xT9gF-4H8f5z-np7NBP-7YYFHF-EHbRQ-P27sR-9NF9Kt-9NF2HM-9NHKmS-9NF77k/

then

https://www.flickr.com/photos/sdasmarchives/6056698329/in/photolist-6i1CAa-oFMeHN-hzQERF-aedapg-aefY47-bT2keD-eJWui6-5YrQiH-qx2EdN-mkYnKx-p4FxgC-aEqMP9-6i1D3K-6i1bwV-67YMnk-aedast-o1tS27-8rvhaR-8tts5x-nWyQJa-7VRvGo-nCiT5p-aefY6A-gkgPpR-qx3TZo-4GrtSH-pkgYC3-7Pu69S-8Az34b-56LgDA-iCXDj3-pj9x9m-pkUnNZ-apsNuV-2MBBUn-9NHGz3-5nuou9-5nq7RD-a2rDcX-9iMtwo-6xT9gF-4H8f5z-np7NBP-7YYFHF-EHbRQ-P27sR-9NF9Kt-9NF2HM-9NHKmS-9NF77k/

then

https://www.flickr.com/photos/sdasmarchives/6057245636/in/photolist-6i1CAa-oFMeHN-hzQERF-aedapg-aefY47-bT2keD-eJWui6-5YrQiH-qx2EdN-mkYnKx-p4FxgC-aEqMP9-6i1D3K-6i1bwV-67YMnk-aedast-o1tS27-8rvhaR-8tts5x-nWyQJa-7VRvGo-nCiT5p-aefY6A-gkgPpR-qx3TZo-4GrtSH-pkgYC3-7Pu69S-8Az34b-56LgDA-iCXDj3-pj9x9m-pkUnNZ-apsNuV-2MBBUn-9NHGz3-5nuou9-5nq7RD-a2rDcX-9iMtwo-6xT9gF-4H8f5z-np7NBP-7YYFHF-EHbRQ-P27sR-9NF9Kt-9NF2HM-9NHKmS-9NF77k/

then

https://www.flickr.com/photos/sdasmarchives/6056698565/in/photolist-aedatk-aefY7N-aedapt-aefY3U-aefXZC-aefXZG-aedah4-8cQQyg-8cQPc2-vsbMa-mcWfj-q6KDqu-fStRYy-bcmpLk-aiFMvs-aiCYMD-aiFMrd-aiFMqy-aiFMjS-aiFMis-aiFMew-aiFM6C-aiFM5s-aiCYik-aiCYgX-aiCY8T-aiCXZX-aiFLDL-aiCXSt-aiFLuC-aiCXrZ-aiCXrH-aiCXmB-aiCX9k-aiCX3n-aiCWVZ-aiFKum-aiCWJ2-aiFJYq-aiFJfG-aiFs89-aiFs1L-aiCCTe-aiFrry-aiCCxF-8cQNTB-8cU7Uo-8cQNSt-8cQNS8-8cU7Tm

then the series continues with an informal parade of the wing and separate fuselage from downtown San Diego to the Dutch Flats landing strip:

https://www.flickr.com/photos/sdasmarchives/6057245992/in/photolist-aefYcJ-aedaup-aedatk-aefY7N-aedapt-aefY3U-aefXZC-aefXZG-aedah4-8cQQyg-8cQPc2-vsbMa-mcWfj-q6KDqu-fStRYy-bcmpLk-aiFMvs-aiCYMD-aiFMrd-aiFMqy-aiFMjS-aiFMis-aiFMew-aiFM6C-aiFM5s-aiCYik-aiCYgX-aiCY8T-aiCXZX-aiFLDL-aiCXSt-aiFLuC-aiCXrZ-aiCXrH-aiCXmB-aiCX9k-aiCX3n-aiCWVZ-aiFKum-aiCWJ2-aiFJYq-aiFJfG-aiFs89-aiFs1L-aiCCTe-aiFrry-aiCCxF-8cQNTB-8cU7Uo-8cQNSt

(That is lucky Lindy in the passenger seat of Ryan's Studebaker, looking back.) There are many more in this series, showing the mating the wing to the fuselage, topping off the tanks with Red Crown fuel, and giving it some test flights. 

And now you know one of the prime reasons I'm modeling San Diego in the Spring of 1927.

[Sokramiketes]

Sorry, what I meant was a single .0015" used as is rather than two pieces soldered together. I get it in rolls. The type of die Lemosteam posted is what I usually use, either in a vise or in an arbor press.

PS it was Robert Culver who wrote the stanchion stamping article.

Andrew Hutchinson

Was it an N Scale Magazine article then?