Correct K4 sand dome @ Keystone Details shop on Shapeways!

[Lemosteam]

I took the plunge and opened up a Shapeways store called Keystone Details.

https://www.shapeways.com/product/B4HV5Q3CE/n-scale-bachmann-prr-k4-replacement-sand-dome?li=user-profile&optionId=58123486

My first offering is none other than a replacement sand dome for the Bachmann PRR K4 offered in a beta sale format until I have good feedback for fit form and function.  Here it is in Frosted Extreme Detail:



The original dome can be popped off after removing the boiler shell and pushing on the pins with a small awl or a pin vise with a 1mm drill in backwards.  Use care when supporting the outside of the shell during this.  Some paint may also come off...

The design uses the original holes and can be glued in place or if you drill a clearance hole for a 00-90 screw directly between the original holes, you can tap the center boss with a 00-90 tap and use a short screw from the inside of the shell, with or without the pins.  I thought this might allow for a tighter fit at the dome flange.

Here is a pic of the dome removed:

[chicken45]

Change the title to "Correct K4 sand dome" for more views!

[Chris333]

So your first 3D item uses all those complex curves and I still can't draw a box 

[Lemosteam]

So your first 3D item uses all those complex curves and I still can't draw a box 

@Chris333 It's what I do and what I LOVE to do.  Don't feel bad, if you have PRR ideas or designs too complex, send them to me!

[wazzou]

Change the title to "Correct K4 sand dome" for more views!

Agreed.

[glakedylan]

this is a wonderful enterprise
it will provide a much needed part
and the thought of other projects in the future
simply awesome
sincerely--
Gary

[tom mann]

Pretty great, @Lemosteam !

[Cajonpassfan]

Not an SPF, so please take this with a grain of salt....
But since the dome is a removable separate casting (that alone wins many points I my book; it should be a "requirement") why not pop it off, rework it, repaint it and put it back? It's too tall, right, so it needs sanding down and reshaping, no?
Just a thought...
Otto K.

[chicken45]

Not an SPF, so please take this with a grain of salt....
But since the dome is a removable separate casting (that alone wins many points I my book; it should be a "requirement") why not pop it off, rework it, repaint it and put it back? It's too tall, right, so it needs sanding down and reshaping, no?
Just a thought...
Otto K.

Because I can buy one now for $5 and turn my brain off. The problem is the two domes on top of the dome. That would be pretty tough to sand down uniformly around them. I think the entire sand dome is too tall so you'd need to sand down everything. Even then, it's hard enough to get a square flat surface at times, let alone something complicated like this. I suppose you could use that JB Weld method where you sand the dome completely and put a drop for each sub-dome but again, time is money. I'll eat five less McDoubles tomorrow and it's paid for.

[peteski]

In addition to what Josh wrote, looking at the earlier photos, the original dome casting is hollow. Depending on how much of the top surface would have to be removed, you might end up with a hole which will then have to be filled.

Nice job with the 3D modeling John!

[Cajonpassfan]

Nice job with the 3D modeling John!

No argument there
Otto

[Lemosteam]

Not an SPF, so please take this with a grain of salt....
But since the dome is a removable separate casting (that alone wins many points I my book; it should be a "requirement") why not pop it off, rework it, repaint it and put it back? It's too tall, right, so it needs sanding down and reshaping, no?
Just a thought...
Otto K.

No worries @Cajonpassfan One Facebook comment from another modeler: "You just saved me and my friend hours of work", and that is in fact the point.

@peteski  is correct though, because the OEM casting is hollow, shortening it is somewhat daunting to have it look ok in the end.  The flange around it is also odd, but that could have been shaved away...

[Lemosteam]

Pretty great, @Lemosteam !

Thank you @tom mann !

[peteski]

No worries @Cajonpassfan One Facebook comment from another modeler: "You just saved me and my friend hours of work", and that is in fact the point.

That brings up a question: Do you know how much time you spent on designing this 3D model?  How much of your labor time it took from taking the  initial measurements to sending the file to Shapeways?  I suspect it was few hours.

The difference here is that after investing that time on this item you can have it duplicated many times without any additional time involved in making more copies.  That is one of very nice parks of Rapid Prototyping.

[eric220]

This is quite awesome!

One question come to mind. The boiler has a pipe running over it and through the sand dome, and the original dome appears to have slots to accommodate the pipe. I don't see the corresponding slots on the Shapeways model. Is this a concern, or am I seeing a problem that isn't there?