What design software do you guys use to design your parts. I have used sketch up and tinkercad. I feel like there are better options out there.
The vast majority of my parts have been designed in OpenSCAD. CoffeeSCAD is nice looking, haven’t gotten the local build to work for me yet, so haven’t done any designs in it yet.
It’s going to largely depend on your budget. Solidworks is the best (I think), but there is some serious spend involved - unless you are a student. There is also Spaceclaim which is cheaper and has a free version (with reduced functionality) called DesignSpark Mechnical. If you are comfortable programming then OpenSCAD is good (and free) and uses a Lisp type language.
Fusion for Mac is Inventor light light light but good for single parts. Blender is powerful… Read: super hard to use.
Blender is great for organic modelling (and not difficult once you get past the initial learning curve), but if you require precision then there are other applications better suited to the task.
Which is not to say that Blender cannot be used for precision design, just that it was not an initial design priority, but here are many add-ons that improve the precision modeling experience.
What limitations did you reach in Sketchup?
I used to use sketchup but got frustrated by having to spend so long fixing mesh problems afterwards in the end I changed to 123D Design. I’m really happy with it I just wish there was a Linux version.
I was in the same situation with Sketchup,but I liked the Sketchup way to design so much that didn’t want to change the design program.Then I made a plugin with separate tools for dealing with every single issue.It is called a http://www.Susolid.com plugin.Another issue is that you need to draw in bigger scale, so like 1mm is 1m in Sketchup,because it seems that Sketchup has trouble to deal with small dimensions like mm.
@FreeCAD is working well for me!
Autodesk 123D design for desktop embodies the tinkercad ux/ui but with powerful construct features. Lots of great resources on youtube to learn, my favorite app. Use it almost on every adafruit 3D thursday project =]
I have been using ‘free’ software - Design Spark Mechanical which I must say is amazing for engineering parts and simple to use. You can go back and change stuff however you want, is a long way from solid works, but I’ve been using it for a few months now and am figuring out all it’s little bits of magic. I would highly recommend it but you should take many of their well produced video tutorials to find out the gems. The catch is that they give you access to this huge library of 3D parts which, after you build your thing you can get a BOM created and then order everything from their site.
@Matthew_Satterlee I tried FreeCAD a few months back and I thought it had huge potential. There was certainly a lot of features but unfortunately it just seemed really buggy and unfinished. It seemed like they had added features but never properly finished or refined them before moving onto the next feature? In the end I got frustrated with it not working properly and changed to 123D Design.
@Tim_Jacobsen looks like Design Spark Mechanical is Windows only as well. @Ethan_Hall what platform are you looking for, I don’t believe you said? I’m gradually migrating my machines to Linux, at the moment Autodesk 123D and Autodesk Meshmixer are two of the few bits of software keeping me on Windows.
@Daniel_Bull , it’s still in active development so there are always changes. I build FreeCAD from source every few weeks and find new stuff and/or polishing each time. Even so, I think FreeCAD has a different emphasis for how things are built, in that it’s more a drafting program than it is for modeling. I typically draft the major surfaces then extrude/pocket them to create objects. It takes some learning but it produces fully constrained parametric models. 
@Daniel_Bull Yes it is run in windows, all my machines (4 others) except this one are Linux you’ll be pleased to know which I’m learning Openscad, though you can install Design Spark Mechanical with wine (but need a windows box to copy it from) http://www.rs-online.com/designspark/electronics/knowledge-item/designspark-on-linux-with-wine
@Daniel_Bull I wonder what OS you use and which FreeCAD version you tried. A lot of people and I along them find FreeCAD very stable and complex designs can be modeled with it. Just visit the Users Showcase part of the FreeCAD forum to find out, or the FreeCAD Google+ community.
@Matthew_Satterlee FreeCAD more of a drafting program than a modeling one? That is so wrong, more like the other way around. As far as open source CAD goes, Librecad is for 2D drafting, FreeCAD is for 3D modeling.
@Rick_Zehr Rhinoceros is not free, it costs a thousand dollars! The free demo is good for only 25 saves that’s it.
Try ViaCAD, it’s not free, but is very affordable. There are different versions.
The toolset grows as you buy more advanced versions. Works on Mac And Windows.