FreeCAD - Gorgeous! I am a little intimidated!

[graham-xrf]

Well, I did my first attempt at CAD based on some tutorials! Making the threads accurately was difficult, FreeCad kept creating a corrupt file when I tried it in PartDesign mode, and the 'difference'/'subtract' for it never worked right, even after copying a few tutorials.

SVG->PNG went poorly, so the text is messed up, but the printout was fine enough for me to machine from at least.

Congrats! You just went for it, in the cause of getting the grinding arbor made. Do not worry that doing CAD "deep end" within hours of learning some of it did not quite make the beautiful full thread image. You really can make great threads. It's only that if the scale of the threads, compared to the size of the object may be very fine detail. Setting the display line thickness from 2 pixels (default) to one pixel may delay the threads crowding together as you zoom out to show the whole arbor.

Helix generation
I get it about the difference between a fully imaged thread - like an ACME lead screw, compared to the threads in some little M3 screw on a panel.. Making threads from sweeping a helix I found to be hard to get right first time, but I know now you can sketch the thread cross-section profile on a datum plane tipped at the helix angle, along a helix path. The whole thread appears, with all the inner helix edges shown.
In the Part workbench, just to the right of the little yellow torus, is the gadget that lets you make the helix. Of course, you may have discovered that already.


"Fake" Threads
In many cases you don't need real threads, just something that looks like them. This is easy to make by revolving a zig-zag, explained --> HERE



Threads in Fixings (Nuts, Bolts etc.), and some routine threads on shafts.
In most CAD software, the modeling of the helix spirals of threads within every screw is seen as unnecessary, and computationally expensive, needlessly increasing build time on re-computes. From the Fasteners workbench, the heads and nuts are seen, but the threads represent as tubes of crest dimensions.

Full ThreadsThe Easy Way --> The ThreadProfile Addon
Here you just "drag and drop the selected profile onto the unthreaded shaft body", and wham! It gets threaded.
I have not tried it yet, but the info is --> ThreadProfile Workbench HERE
My apologies if you already knew this. I include it for others who might be reading it.

I also have to go this route with threads. I know that ACME threads are already out there, and I will find it again.
Also, if it was done well, it is probably on YouTube already!

Here I just started the Fasteners workbench, and threw in three simple representation random bolts (temporarily)


Add-Ons
This is where you select Tools --> Addon manager, and start clicking on the workbenches you want added on. They automatically get fetched and installed (or updated). This is where the Fasteners workbench came from. Check this out. It is where you get the 3D_Printing_Tools

Erich, for you, once you got the drawing (which means you already figured out the TechDraw workbench), you did not need to explore FreeCAD any more. You went on to be making the arbor. That should give hope to some HM members who think they haven't got enough life left to tangle with it.

My point is.. one can make it useful without learning the whole thing to expert industrial designer level. There is so much there that even expert industrial designer will never get to use all of it, if only because the various applications are being added too fast!

 

[graham-xrf]

Now that I have seen it, I am definitely going to play with the ThreadProfiles Workbench.
I want a good ACME leadscrew model!

Who else is thinking that if this is @ErichKeane 's first try, and that given he first downloaded and compiled FreeCAD from source code, that makes him a very smart HM member?

 

[7milesup]

Now that I have seen it, I am definitely play with the ThreadProfiles Workbench.
I want a good ACME leadscrew model!

Who else is thinking that if this is @ErichKeane 's first try, and that given he first downloaded and compiled FreeCAD from source code, that makes him a very smart HM member?

Most likely a very smart HM member but there is always the outside chance that even a blind squirrel can find a nut occasionally...

 

[middle.road]

Hey 'Nix Fans, which distro(s) are you running it on?

 

[ErichKeane]

I just did the appimage one, which works great too! I thought that would be easier to upgrade I'm on ArchLinux, with i3wm as my window manager.

 

[graham-xrf]

Hey 'Nix Fans, which distro(s) are you running it on?

Mine happens to be Linux Mint 19.3 with "Mate" desktop. The engine would be Ubuntu 18.04.
I am tempted by a Debian engine version in Mint's LMDE.

Erich's distro is ArchLinux.

Something else concerning platforms and distros I have noted. As with all CAD software, when you casually throw on a model feature that can get computationally intensive too early in the build, you have to sit through the pause, while it re-builds between operations. This is where the faster computers can show their stuff. I haven't yet looked close at how the software handles threading, but I think the math engines uses all threads in all cores simultaneously, if it can. The "speed" of a distro may be affected by all the eye-candy and dandy desktop stuff in the more heavyweight distros.

[Tip: If you want to add a beveled edge, or filleted edges everywhere, or add in a row of tiny screws, do it at the end of the build].

Windows
Among the last stuff I would have to do in a Windows PC was an "electronics" software that actually ran faster in Linux under "Wine", which is a software layer that runs Windows applications in Linux PCs. This was compared to the Linux distro on a different partition in the very same PC. There is something going on in the Windows (8) that seems to be busy doing "something". That PC hardware is now re-purposed.

Maybe FreeCAD zips along just fine in a Windows PC. It must be OK, because thousands are doing it!

The Linux being used in the JOKO engine head example.
In the top left-hand corner, there is a Ubuntu logo. The rest of the desktop looks like a KDE Plasma desktop, or possibly Evolution. Whatever it is, it's full of gizmos. Wobbly windows is a Compiz graphics trick that I would have thought would slow things down, but it does not seem to. He did say that they edited out the re-build pauses, so we wouldn't get bored. Even so, it's long video (hours).

 

[graham-xrf]

The Time-Lapse Engine Head.
Folk in this thread may have come across it by now, but here it is anyway..
-->

3 minutes and twenty seconds.

Spoiler: From 2:37 onward you get variously..
Engine interior animations,
Round ports head display
Colour Combustion Flamefont Visualization
Rootes type Oil Pump Compressor (animated)
Flowed Manifold port
(Briefly) Piston model to TechDraw output.
Wankel Rotor animation
Manifold gas velocity analysis and visualization

It's short enough to be an eye-opener while still being fun!

 

[ErichKeane]

FYI: I did some research while compiling FreeCAD, it does NOT do anything in a separate thread. They have a Feature Request to do so, but they haven't done much on it yet.

I'm running off a 5 year old i5 laptop, so doing the threading on FreeCAD made it chug pretty slow! If I were going to do this more seriously, I'd definitely have to invest in a nice desktop.

 

[graham-xrf]

Hmm - I thought OpenCascade, and some other Linear Algebra engines did. I got misled by System Monitor, which fires up like in the picture, but who knows how much of it is entirely there for FreeCAD?



I am with you on the hardware upgrade. (We all love it when Santa brings us a new motherboard & PU & SSD & etc.)!

 

[middle.road]

I've got an older SandyBridge i7 w/ only 8GB sitting on the bench running Mint 18.3
Might just have to dust it off and move it to my desk where the good monitors are.
Dig out an SSD & upgrade it to 19 and try it out...