The Barth Type Caster

New Engineering Models and Drawings

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These Notebooks will contain digital 3-D models and derived engineering drawing of Barth type casters, with an emphasis on the 60-point No. 3 size machine.

For other kinds of drawings, go up one level for:

Contents:

1. CAD Issues and Systems

I swear sometimes I'm tempted to pull out my dusty but very nice set of antique drafting instruments and draw the Barth the same way Henry Barth did in the 1886. It worked then, it would work today. CAD introduces problems which are insoluble - and not just insoluble for amateurs such as myself who are trying to do it on the cheap. The CAD industry itself is, not to put too fine a point on it, fubared. We'll learn this two generations from now, when historians discover that virtually no engineering data survives in readable form from the start of the 21st century.

There is no universal standard, either open or proprietary, for CAD models which preserves the full functionality (including history) of the design. The international standards, IGES and STEP, aren't sufficient. Proprietary formats from commercial vendors (SolidWorks, Autodesk, etc.) are useless precisely because they are proprietary. Nothing else even comes close. This means that any use of CAD from its origins through the present (and forseeable future) is doomed. We can read engineering drawings from 1916. Our CAD models of 2016 will be black holes to the engineers of 2116.

In a way this simplifies things: use whatever works, and make darned sure that you generate real 2-D engineering drawings (you need them, still, for proper GD&T anyway).

For those on a budget, there is no good open source 3-D CAD (for a 2014, pre-Onshape, review see the now slightly obsolete CircuitousRoot Notebook Reviewing the Options for Digital Drafting and Modeling).

There are now several good free (but not open) 3-D modeling options, but only one of them (the free version of Onshape) is actually a CAD program. Modeling is not CAD, even if you can make nice things on your 3-D printer.

There aren't even any good low-cost (< $1k) proprietary 3-D CAD options. (I tried one, purchasing Geomagic Design (formerly Alibre) in 2015. I wish I hadn't.) Until very recently the only way to really get into very good 3-D CAD was to plunk down many thousands of dollars to get SolidWorks.

There's now (2016) an attractive alternative: Onshape ( www.onshape.com ). It's still in its early stages, and isn't yet quite as capable as SolidWorks, but it's improving very rapidly. More importantly, it also has an extremely usable free-cost plan (full functionality, but limits as to the number of models and/or online storage). I'm actually subscribed now at the "Professional" level (that is, paid, for a single individual), but I got along at the free level for over a year.

The thing about Onshape is that it's "cloud only." This is Newspeak for a return to 1960s datacenter technology. It runs on their servers (actually, I think it runs on Amazon's servers) and you access it via your browser or a mobile device app.

This actually makes it very easy for me to share the models. You can view them read-only even if you don't have a (free or paid) Onshape account. Here, for example, is my model of the No. 3 1/2 Barth (very incomplete now, of course) - click on this link:

https://cad.onshape.com/documents/79a9755c99ee470e9853ae64/w/a4f523619f5145c6be2147fe/e/e149c41b768c4780bc29c988

You should get to a screen which looks like this (well, I hope that soon it will have a more complete model!):

[click image to view larger]

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The link above shows you the model in read-only view, without requiring you to set up an Onshape account.

If you do have an Onshape account, just search the Public models for "BCD - Barth Caster D" and you should find it. You can then copy it to your own workspace and, if you wish, modify it. Although Onshape doesn't have a convenient place for me to say so, it is licensed under the Creative Commons Attribution-ShareAlike 4.0 International license.

2. Specific Models

Note: these models are all CircuitousRoot Open-Source Hardware Projects.

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BCA, Barth & Lietze Patent 376,765

The type caster as described in Barth & Lietze's US patent 376,765 (issued 1888). This is a reconstruction, insofar as it is possible, of the machine from its patent specifications and drawings. It does not represent any machine as actually manufactured. I probably won't bother with 2-D engineering drawings.

[STATUS: NOT YET STARTED - the purpose of this model is to provide technical illustrations for an analysis of the Barth as patented; I haven't yet really begun that analysis.]

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BCD, the Size No. 3 1/2 Caster

This is a digital 3-D model, with derived 2-D engineering drawings, of the Size No. 3 1/2 Barth, based primarily upon the surviving "60 point" machine (Machine ID: 112, Mold Configuration: 6003).

[STATUS: BARELY STARTED] But here's a link to the Onshape model, such as it is so far: https://cad.onshape.com/documents/79a9755c99ee470e9853ae64/w/a4f523619f5145c6be2147fe/e/e149c41b768c4780bc29c988