a newbie's take on the A3 switcher

[Mike R]

Agree with Kim, a little oil and the truck should be fine.  They should free up with some running. 

Mike

[Pogo_proptie]

hey guys i need your help for this mini update.

before i cut 40 $ of copper i want to run my numbers by those who did it. 

the plan is a bit weird to me.

do you think that the layout is ok for the 2 intersecting radii with the flat front part




on the second one i showed the way i THINK it's supposed to be but I am not sure at all if it's the correct way to offset the center of the 1.23 Radius thank you.

and boy do i have a nice skateboard to show you later

POGO

[Pogo_proptie]

time for an update. i'm having so much fun the past weeks and trying stuff i never did.

looks like i forgot to document the frame but hey.. it's mostly DRO magic



now the floor was much more stressful and, according to quinn the biggest piece in the whole build.

so i started to try and get it to dimension AND square. wich is quite easier said than done on el cheapo mills with not enough travel to do it all in one setup.



i believe i did very good in the end, (certainly close enought to the book's tolerance wich seem to be carefull filling).



to do the whole i have only enough Y travel to do it in halves so with carefull edge finding and not rushing the inversion i did patern without mistakes.


with the floor on this thing is SO RIGID, it feels like those patio tiles made of cement when  I hold it.

next was the oak former.

fresh out the router.

and the fun part started with a lot of anealing and a lot more beating. (those corners are very difficult to flatten)

here it is before the ''surgery''


and just after



a bit of filing and plumbing solder later i had this.



and now i have this



i can measure 10 thou diff to the front of the floor so I am calling this a very good and i am extremly pleased with the progress.. the heavier it gets the more satisfying the roll is.

i just came back from my brass supplier with enough material to make it all the way to the loco frames and bumpers. probably enought stuff to last until holidays until the next trip to the metal shop.


thanks for watching

Pogo

[crueby]

Beautiful tender parts! The sides formed out great!  Are you using brass for the frame and floor? Looks like it in the pictures, but that could be lighting. If so, nice to see someone else who likes it that much!   

[Kim]

Beautiful work on the chassis and formed sides, Pogo!  Great work! 
t really is fun to see it all come together from a pile of bar stock, isn't it?

And Chris, just so you know - it's not that I don't love working with brass, because I do.  I just don't like paying for brass! 

Nice update, Pogo, keep them coming!
Kim

[Pogo_proptie]

hey group.

not dead just not posting much but progress is happening..

i do have a question on the front plate and the riveting.

how did you prevent the piece going all banana

this is my 1st one and i foresee a lot of grief fitting that flat with a big curve





let me know if you have some tricks/ideas

sorry for the big picture made this in a hurry .

thanks as always

POGO

[crueby]

Looks like typical brass turned Bananium when one side is cut away. It gets stresses on the surfaces when they roll it in the factory, and cutting one side away makes it warp the other way. Solution is to degrease it then bake it in the oven at 500f for an hour and let it cool. That relaxes the stresses so it takes no or at least very little warp. I do that on all my brass and bronze stock that will be cut lengthwise. Bars to be turned on the lathe doesn't  need it since all sides are taken away evenly. This does not anneal or soften the metal, just stress relieves it. This recipe does not work on steel, each alliy has a different temperature  and time requirement.


Hope that helps!  The piece you have already hopefully  can be bent back straight enough!


Chris

[Pogo_proptie]

just wanna know if this is the correct phenomena crueby. the banana appeared when i punched the rivet, not when i cut it.. will cooking it as you say help anyway?

[internal_fire]

just wanna know if this is the correct phenomena crueby. the banana appeared when i punched the rivet, not when i cut it.. will cooking it as you say help anyway?

I think this is a different cause and effect. Almost any flat strip will curl somewhat when it is formed by pounding on one side. Indeed, that is a standard technique for making curved surfaces.

Just gently straighten it back by hand. A sheet roller could also be used if you have one.

You can "minimize" this effect by pounding on a hard substrate, not wood, for example.

Gene

[crueby]

just wanna know if this is the correct phenomena crueby. the banana appeared when i punched the rivet, not when i cut it.. will cooking it as you say help anyway?

Ah - sorry, I misunderstood the picture and thought your were milling on one side.  Gene is right, punching through or any hammering on one side will deform the thin stock, and stress relieving it wont help that. I wonder if drilling rather than punching the holes would give better results? Use a spot drill first to make the dimples for the final drill to locate in and resist skating on the surface. When drilling really thin stuff I'll clamp it between two blocks so the drill doesnt grab and lift the sheet.

[Admiral_dk]

Are we talking about punching Holes or punching Rivets ?

If it is Rivets - I believe that a bunch here have made a 'Plier' for doing this so you don't have the problem.

Per       

[Kim]

Hey Pogo,
Yeah, I remember having a little bit of bending like that when making the rivet patterns on the long thin parts.  I just gently curved them back to mostly flatish and it all seemed to work out fine.  I don't think you're doing anything wrong.  Like Gene and others have said, this is what happens when you're working on one side only of a thin sheet like this.  I'd be careful of trying to flatten it with a roller though as you're likely to flatten out the rivets you spent so much time and care putting it!

Kim

[Pogo_proptie]

good news hitting the top side of the banana on my vice's anvil with my copper hammer made it 80% flat.. so now its shallow enough that fixturing it wont be difficult i think.. now its credit card flexible i'd say..

suck a cool thing to learn.. love those old school technique..

thanks for the help folks. a bit update coming if i can finish the big tank panels

[Pogo_proptie]

i need you help guys.. i was all smiles screwing the top plate until once really snug in place i sqeeze the aft part and looked for the gap at the round part and this is the result.



my gut tell me that this will not solder well.

my first idea is to remove the floor since it should hold itselt reasonably well and sqeeze it tight with the curve, and sand whatever is to much..

i'm looking this community's input before going farther.

[Kim]

my gut tell me that this will not solder well.

Yeah, I think you're right.  That's a huge gap even for soft solder to try and fill.

my first idea is to remove the floor since it should hold itselt reasonably well and sqeeze it tight with the curve, and sand whatever is to much..

Not a bad idea.  You've already got much of the top plate attached to the sides with screws, right? So it should hold the correct shape & distance.  So just disconnect the sides, coal bunker, etc, from the base plate, hold the back of the top plate in position, and sand it down.

The other thing you could try is to remove the top plate and sand the plate shorter on the end. I believe that's what I did.  I had it fitting pretty well there prior to putting all the screws in place, so this is possible.

I'd lean toward your first idea unless things don't seem stable after you get them disconnected from the base plate.  Then you might try the second one.  I'm thinking it should be pretty solid though.  I'd try that first.  It won't cost you anything to disconnect the base and see if it feels like it will work?  If so, it should be fairly easy to sand the end of the top plate down to the correct height.

Kim