Mutually Assured Alignment

I’m telling you this because, in a few months, you might be me, and we will want to take advantage of some of the cunning plans that we laid in the summer. We’re going to attempt to fold the crossheads up from etched material.  I’ve put four of them on the etch because there’s loads […]

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Etching pattern begins

As I start work on the pattern for etching, there is good news and bad news. First the good news: it appears that OnShape have improved the compatibility with Inkscape, and so, now I can take flat patterns from OnShape and import them directly into Inkscape without traversing through QCadCam.  Someone is still resizing the […]

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Virtual dry fit for 622

In typical Panglossian fashion today, I uploaded the STL file for 622’s plastic parts to Shapeways.  I might have hit the big “Print” button, if the bounding box hadn’t precluded the use of their highest resolution machine. It’s a good thing I didn’t because the pause gave me an opportunity to assemble all the parts […]

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All the parts that are fit to print

I’m just about ready to upload all the printed parts to Shapeways.  To support some of the more delicate parts for printing, and more importantly for shipping, I added some sprues.  I actually started out making a sprue for all the parts, but then I re-read the pricing guidelines for Shapeways and concluded that this […]

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Mud drum plug

The erection drawing for this engine clearly shows a mud drum hanging like a uvula from the bottom of the boiler. Extending from this appendage, the drawing also shows a two-foot lever. This puzzled me for quite a while: surely you would have to unbolt the cover to gain access, and a lever wouldn’t be […]

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Boiler keyhole?

Okay, it may be time to admit I have a keyhole problem.  Ever since watching Dan Gelbart’s videos on prototyping, I’ve been thinking about them.  This latest design element might be a keyhole too far. What if, instead of screwing down through the smoke stack to hold the front of the boiler in place, I […]

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Lance Mindheim on Time

A great post on Lance Mindheim’s site caught my attention at lunch today.  Here is the critical idea, but you should read the whole post:  The hallmark of a good design?  It’s pretty basic when you step back and think about it.  A “successful design” is one that results in a model railroad that produces […]

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To pivot or persevere…

Mark Dance made a great observation on the previous post: Pivot towards something that looks more promising when your existing path is not successful and your rate of learning on it is slowing down. Of course, you don’t know if your rate of learning is decreasing until you have three attempts.  As my mother used […]

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