Lets Talk about Engine Drawings

[a41capt]

a41capt said:

My projects in my drafting classes (1965 to 1970) always ended with ink on vellum, including the hand lettering (anyone else remember TOM Q VAXZY? ). I’m not sure I could still ink with a lining pen, or even think of a reason to try! Nothing more fun that watching the ink run under your triangle on the vertical lines…

If you’re doing that kind of work GreenTwin, I’m definitely impressed!!!

John w

I would not say I am doing Kozo-level work, although I did learn pen and ink on vellum in drafting classes back in the 1980's, and made all of my engineering drawings by hand in the pre-CAD pre-computer days, using pencil on vellum, and sometimes ink on vellum (generally ink was used for Leroy lettering).

But rather I try to mimic the Kozo-style of layout, flow, spacing, clarity, contrast between various lines, etc.

Kozo is the master.
I am a little Kozo wannabe, and I understand I will never be a Kozo.

Below is an example of Kozo's work from Live Steam and Outdoor Railroading, Jan/Feb 2020, Vol. 54, No.01, pages 36, 37.

What I like about Kozo's work is the variation in line width, which gives 3D depth to a 2D drawing, the absolute clarity to each part, the dimension layout and spacing, and the dashed leaders showing association with mating parts in his isometrics.

Not only does Kozo produce very clear and useful drawings, but in my opinion he produces works of art too.

His top, side, left, right, bottom, views always align with the front view, and in general, the drawings are intuitive to read and understand.

View attachment 146841

Yep, truly beautiful work, and the line width issue was why we were taught with lining pens. Heavy lines outlining part drawings, finer lines detailing dimension extension lines, finer lines still for dimension lines and arrow points,

Fine lines for sectioned drawings, on and on, and on. Lots of hard work and an occasional ruined drawing with not paying attention, not to mention waiting for ink to dry on vellum, but the blue line prints at the end were SO worth it! No such thing as computers and plotters with reproducible work back then…

Thanks for sharing GreenTwin!

John W

 

[GreenTwin]

I often gauge my work based on a comparison with the work of others.

One of my comparision people is JasonB, and I have sort of a Richter scale thing, where if I think I did particularly well with a design or build, I say "Wow, I hit a JB5 on that one", or an "RC2" (Rich Carlstedt).

Kozo is in a league of his own, so I don't have a scale for him.

.

 

[Zeb]

I really got into paper and pencil after reading through Kozo's Shay. The perspective and iso views are so good, and he makes every line count to draw the eye to the point of interest. I try to apply some of his work when I illustrate non-geometric forms.
The thing I like about JDW's drawings is that everything is in one place, so I can verify how the parts will fit together without jumping across sheets. I haven't built to them, but PM uses a similar approach.

 

[Richard Hed]

What Julius's drawings have done is made it clearer for a lot of people coming into the hobby with no engineering background to "see" what a part looks like and how they go together. Yes his drawings are cluttered but teh isometric images and assembly drawing are both things you seldom see and can be a lot easier for those not used to reading technical drawings to understand.

He also works exclusively in metric which again many now coming into the hobby will have been brought up on and have a problem understanding fractions and things like threads that have odd #numbers rather than the diameter.

Absolutely, I REALLY like his 3D, isometrics, and cut views. They are absolutley top rate.

 

[GreenTwin]

Looking at Julius's Bernay drawing again, now that you mention it, he does add several detailed sections, which I had never noticed.

I like sections, but in a complex piece, I often have trouble interpreting the sections, such as the old school 2D sections.

The 3D sections are an improvement over 2D sections for sure.

What is really helpful to me is 3D models with the surfaces turned translucent.
This helps me visualize what the coreboxes will look like.
It also allows me to check for clearances and interferences.

A few examples attached.

Hidden line isometrics are nice, but I prefer full 3D isometrics with translucent surfaces.

 

[GreenTwin]

I also like assembly drawings, such as front, top, right side.
I derive assembly drawings from the assembled parts in the 3D modeling program.

The 3D motion study assembly is really the acid test for an engine design.
If you can assemble the parts in a motion study, and the engine will run in simulation, chances are you have a good workable design.
If the parts don't mate correctly in Solidworks, the engine will not run in simulation.

.

 

[Richard Hed]

Looking at Julius's Bernay drawing again, now that you mention it, he does add several detailed sections, which I had never noticed.

I like sections, but in a complex piece, I often have trouble interpreting the sections, since they are still 2D drawings.

The 3D sections are an improvement over 2D sections for sure.

What is really helpful to me is 3D models with the surfaces turned translucent.
This helps me visualize what the coreboxes will look like.
It also allows me to check for clearances and interferences.

A few examples attached.

Hidden line isometrics are nice, but I prefer full 3D isometrics with translucent surfaces.


View attachment 146885

View attachment 146886

View attachment 146887

View attachment 146888


View attachment 146889


View attachment 146890



View attachment 146891

Yes, JDs 3D and sections make it quite clear what is up. Howeveer, I have seen his work where he needed a backview in section. Minor deal.

 

[GreenTwin]

I have talked to a number of folks who really like Julius's drawings and drawing style.

We all have our preferences, and reasons for those preferences.

From a scratch design standpoint, compacted drawings would not work for me, because I always need to add one more dimension, or strech a part, or something that takes a bit more room.

Using colors is a big plus, and that helps me greatly with visualization.

I am very claustrophobic, and about half dyslexic, and that definitely impacts how I set up my drawings, perhaps in a subconscience way.

.

 

[johnmcc69]

Some great insight & examples here. It's good info to take in for what model engine builders would like to see & good for all the new designers to aspire too.

Brian Rupnow has been a huge contributor to this site (& others) & his drawings are very well done, not only does his thoughts start out as computer "Scratchings", but they end up as working models. You can't argue with that, alot of folks have bought Brians plans & have been happily surprised to find they have a running engine at completion.

Another one is Vederstein (Ved), who spends alot of time engineering models ,builds them, & posts his plans.

Elmer V. & Rudy K. were vey good at what they did, Elmer's drawings were very well done & many of his engines were built. I very much admire these fellows for the work they did, inspiring me...

Standards be damned. (Kind of...)

To a hobby machinist, we dont need alot of the extra "Fluff" like geometrical tolerancing & some other "Standards" involved in building an engine. These things are required in modern industry, but is cumbersome in model engine drawings.

John

 

[johnmcc69]

I've worked in the design field for "Awhile" & have learned more from the fellows "on the floor" what they need.

What I try to do:
First off, a good drawing with the basic views of the part/assembly & an isometric view of it & a complete bill of materials. The following pages show the parts/assembly in "Exploded" views, these view show how the assembly fits together & makes identifying parts easier. In the BOM, I also have a column where it tells what drawing that apart may be.

I dimension parts as I see fit.

I don't like cramming parts on one sheet, I have a printer that will do 11 X 17, so I do all my engine drawings on a "B"size sheet, usually only a few parts.

John

 

[littlelocos]

My definition of "bling" is anything added to an original old engine design, but that is just my definition.

Some folks like to modify old designs in many ways, and that is part of the fun for a lot of builders.

To each their own; I can only state my own preferences.

.

When I take on a previously-designed / kitted engine I tend to rethink the entire design as I go through it, refining it as what I imagine would be the next step the original designer of the kit would have done anyway. For the 1/4-scale NH, I narrowed the hopper walls, added a bead around the top, and redesigned the exhaust valve flange from a rough rectangle to a proper flange. These are refinements for aesthetics and functionality. I have three different versions from the original designer, so mine becomes the fourth. It's interesting to have the earlier versions and to see the progression. The attached photo is the "new" casting 3D printed, between a cast iron casting and two machined bases.

Admitting that as a long-time mechanical engineer and it's difficult for me not to do this anyway.

 

[littlelocos]

a41capt said:

My projects in my drafting classes (1965 to 1970) always ended with ink on vellum, including the hand lettering (anyone else remember TOM Q VAXZY? ). I’m not sure I could still ink with a lining pen, or even think of a reason to try! Nothing more fun that watching the ink run under your triangle on the vertical lines…

If you’re doing that kind of work GreenTwin, I’m definitely impressed!!!

John w

I would not say I am doing Kozo-level work, although I did learn pen and ink on vellum in drafting classes back in the 1980's, and made all of my engineering drawings by hand in the pre-CAD pre-computer days, using pencil on vellum, and sometimes ink on vellum (generally ink was used for Leroy lettering).

But rather I try to mimic the Kozo-style of layout, flow, spacing, clarity, contrast between various lines, etc.

Kozo is the master.
I am a little Kozo wannabe, and I understand I will never be a Kozo.

Below is an example of Kozo's work from Live Steam and Outdoor Railroading, Jan/Feb 2020, Vol. 54, No.01, pages 36, 37.

What I like about Kozo's work is the variation in line width, which gives 3D depth to a 2D drawing, the absolute clarity to each part, the dimension layout and spacing, and the dashed leaders showing association with mating parts in his isometrics.

Not only does Kozo produce very clear and useful drawings, but in my opinion he produces works of art too.

His top, side, left, right, bottom, views always align with the front view, and in general, the drawings are intuitive to read and understand.

Agreed on all counts. Kozo is the master of clarity. .....and I'm pretty sure he's still producing drawings by hand at 2X the scale in the magazine. For that, I can't even come close. Line widths add a huge amount of legibility to the drawing. I usually use one weight for solid lines and a lighter weight for dashed, hidden, phantom, center, etc. This helps and is easy to do with CAD.

What I'd really like to figure out is how to render in 3D using the style of 19th and early 20th century etchings. I "know" how to do it by hand with drafting pen and ink, but haven't tried with CAD. TurboCAD used to have an advanced rendering style that replicated a shaded pencil sketch. Loved it. It's gone. The attached rendering is a freelance engine I have in the hopper to produce sometime in the future. It's from 10 years ago so it's officially a long-term project.

I've even toyed with the idea of printing a CAD 3d sketch in a very light line weight on vellum and then hand inking it, scanning that, and then using it on the Cover page of the drawing set. Would that be wrong?

 

[GreenTwin]

I've even toyed with the idea of printing a CAD 3d sketch in a very light line weight on vellum and then hand inking it, scanning that, and then using it on the Cover page of the drawing set. Would that be wrong?

I think that would be cool.

I tried mimicking some of the old school shading/line width (is the correct term lithograph? I forget).

That was definitely an art, and I have not seen anyone in modern times replicate that.

I will look for some old lithographs.

.

 

[GreenTwin]

I am not sure if you would call these engravings, lithographs, or what.

Some beautiful and no doubt tedius hand work for sure.

.

 

[GreenTwin]

A few more.

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[GreenTwin]

Some of these drawings vary the line width on curved surfaces, and vary the line spacing with a constant width line for flat surfaces.

There is a lot going on in some of these drawings, and one has to look carefully to see how they achieved the 3D affect.

Other surfaces solid, or blank.

Edges typically very bold, with the closer edges more bold tan the ones further away in some cases.

Such as this one, for example.

It is all just flat lines on a flat sheet of paper, but looks very much 3D in appearance.

.

 

[littlelocos]

@GreenTwin. Thanks for posting those. I could look at them for hours. I have a book on machine sketching from the time period. I'll see if I can find it tomorrow. Thanks again!!

 

[Zeb]

Rendering shaders can do a pretty good job, but they require a lot of setting up and still lack control. It's a bit like CNC, where after careful setup you can throw any models at the shader, but it still looks like it came from a computer.
Some goofing around this evening...

 

[Jasonb]

The other method that was used was to apply a water colour wash, this could be done from a printed out image, an example from my ever growing "to buld" list may be possible by using very light tones of colour for the various parts and applying model shadow.

The other option for the cover of your build manual would be to take a photo of the finished model and use a sepia or B&W filter, this is a Heinrici I scratch built but gave it a weathered paint finish. There are filters that will make it look like a worm old photo to further add the effect that it is an old original engine

This is another filter that would make it look like an old catalogue image

 

[littlelocos]

Rendering shaders can do a pretty good job, but they require a lot of setting up and still lack control. It's a bit like CNC, where after careful setup you can throw any models at the shader, but it still looks like it came from a computer.
Some goofing around this evening...

That's got a really nice look to it.