There comes a time in every fabricator’s life when they realize there’s an asymptote in the home garage. No matter how skilled you are with a grinder, how straight your hacksaw cuts, or how steady you can hold that hand drill, there’s an invisible line of quality and accuracy that you can approach–but never cross–at home.
We’re talking about those …
Just drawing a sketch of what you want and putting some dimensions on it and making sure those dimensions make sense will got a long way to making a good looking fully functional part.
Learning what functions to use, what they are called, and which program buttons to push can be intimidating. Key is to commit the time to go at your own pace. Eat that elephant one bite at a time...
I'm happy to say that I almost never use technical drawings. 99.9% of stuff I work on is made directly from the cad, no drawing needed.
What we REALLY need an article about is how to print STRONG prints (layer grain direction, filament type, flexibility, etc).
I can print things in Petg and ABS, but can I use it to make suspension bushings? How about sway bar brackets? Intake manifold? Air filter adapter? Oiling system components? Turbo brackets? Etc?
There's a big difference between making parts and making precision parts. Precision parts need to interact in specific ways with other parts. For precision parts you have two choices: make it yourself and customize it by hand with files and sandpaper, or generate a print with geometric dimensioning and tolerancing to let someone else make it. Doing the design and making the drawings is as much of an art as making the final parts from the drawings.
Can you share a list of the YouTube videos you watched and found helpful. Thanks!
Sure; I found this series extremely helpful:
In reply to Tom Suddard :
That's a good article, Tom. Thanks!
ProDarwin said:I'm happy to say that I almost never use technical drawings. 99.9% of stuff I work on is made directly from the cad, no drawing needed.
CAD is a technical drawing. Just doing it with a computer, hence the name Computer Aided Drawing
porschenut said:ProDarwin said:I'm happy to say that I almost never use technical drawings. 99.9% of stuff I work on is made directly from the cad, no drawing needed.
CAD is a technical drawing. Just doing it with a computer, hence the name Computer Aided Drawing
CAD is Computer Aided Design. It can mean many things, but often it is either 2d lines, 3d models, surfaces, etc. Technical drawings are created from those designs. We skip that part most of the time, and there is a general movement in that direction - see https://en.wikipedia.org/wiki/Model-based_definition
ProDarwin said:porschenut said:ProDarwin said:I'm happy to say that I almost never use technical drawings. 99.9% of stuff I work on is made directly from the cad, no drawing needed.
CAD is a technical drawing. Just doing it with a computer, hence the name Computer Aided Drawing
CAD is Computer Aided Design. It can mean many things, but often it is either 2d lines, 3d models, surfaces, etc. Technical drawings are created from those designs. We skip that part most of the time, and there is a general movement in that direction - see https://en.wikipedia.org/wiki/Model-based_definition
In the old days (1980s) when CAD was loaded via a 5.25 floppy and machines didn't talk to computers without punch tapes CAD was a drawing only tool for most of us. The term for design to build was CAD/CAM. You can quote wiki all you want, I was there and none of my vendors had the ability to load a CAD drawing into any machine. Th evolution was fast though.
porschenut said:In the old days (1980s) when CAD was loaded via a 5.25 floppy and machines didn't talk to computers without punch tapes CAD was a drawing only tool for most of us. The term for design to build was CAD/CAM. You can quote wiki all you want, I was there and none of my vendors had the ability to load a CAD drawing into any machine. Th evolution was fast though.
it's not 1980 anymore
I thought CAD meant Cardboard Aided Design?
(JK I use CAD at work everyday)
Figured I should add my latest CAD project to this story. I needed a bracket to mount an oil pressure thermostat, and made it myself with what I learned writing this series. 
Nice work. What brake did you use to form that? How accurate are your bend deductions?
I used the finest imported vise brake available on Amazon. And I'll admit I didn't check my bend deductions. I was in a hurry and it fit first try, but I should check them before I build anything real precise.
Well done sir.
Yeah, check them then put the math back into your software and you can build some super precise stuff... not that you really need to in this world, but its fun to do anyway.
Yeah, good point. I'll give that a try.
I stayed safely on my side of the invisible line of quality
A little advice from a Die maker. Inside radii should be at least a material thickness. Bend allowance should be calculated through the middle of the part based on the inside radius and material thickness.
I'm finally forcing myself to learn CAD, using it to design a CNC router. Learning it now is helpful because once the router is built, CAD (technically CAM) files are necessary to make the router actually do something.
Below is the result of two weeks of self-teaching, starting from nothing and knowing little about this CAD package, using Alibre because it is Not a subscription product. There are just so many moving, interrelated, and precisely aligned parts that having proper drawings are a requirement, not a nice-to-have.
I bought a manual lathe and mill a few years ago and then did the YouTube thing to learn to use it. After watching many, many videos by a variety of talented guys, I found myself watching Joe Pie on YouTube more than anyone else. He still has an active machine shop and gives very focused instruction with occasional white board illustrations. He is worth checking out.
On a different path, I started 3D resin based printing a few years ago, that that made me start doing computer models for CAD work. That led me to the company below.
While working on this other project, I had xometry.com do several jobs for me and was very satisfied with them. They can coordinate manufacture of almost ANYTHING in any material, with pricing tied to time frame.
I would encourage anyone reading this article to look into getting at least a small lathe and mill. I work on motorcycles a lot and got a 7 x 16 lathe, which is quite small. A vast majority of the parts I make are spacers and brackets, so this lathe is great. If I need to have a big part machined, which is rare, I take it to a pro. I got my lathe and mill and most tooling from littlemachineshop.com, but micromark.com also has great stuff. A positive for getting small equipment like this is you don't need a fork lift to move it around. That alone was what made me go smaller than I planned.
Alternatively, there is nothing like a big Bridgeport mill and similar lathe, but the sheer size can be a problem for a home garage shop.
The last comment is there are few things in life that are more gratifying than taking a chunk of raw metal and turning it into a car or motorcycle part!
Why do you need a technical drawing?
Because when the berkeleywads in the god damned fab shop make E36 M3 wrong and the boss starts yelling at you without first asking what happened, you need to be able to point to your drawing and be able to say "hey, screw you, buddy!"
I'm not on board with relying on the model, even if you fully dimension your sketches. The drawing is an important part of defining the critical reference point and dimensions required for a part.
The model can be dimensioned a million different ways, and not all will produce the same result when you start adding tolerances and doing a tolerance stack for the assembly. Start to include GD&T and the models don't provide nearly the level of control that a drawing can (not to mention bonus tolerance for MMC and LMC).
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