Universal CAD of Socket Head Cap Screw, Hex Nut and Nylon Insert Nut

Ever wanted to change which screws you’re using for a design, but begrudge the effort of downloading the new screw CAD and going through the ‘replace components’ process in SolidWorks? I use a lot of socket head cap screws in my designs and often I want to change their size or length as I go. I’d always wanted to learn more about design tables in SolidWorks so I set out to create one part that could be reconfigured to any size and length of socket head cap screw I could possibly need. I designed the screw using as few driving dimensions and as many equations and relations as possible and then populated the design table parameters with data I obtained from the CAD models and drawings provided by McMaster-Carr online.

Once I had the screw model working I decided to take it one step further to automatically generate mates required to locate the screw in an assembly. I used mate references in SolidWorks and set the part up so that the necessary concentric and coincident mates are created when the user drags and drops the part in to an assembly near a hole.

To complete the set, I also created a hex nut and nylon insert nut following the same procedure. I know it’s a tiny portion of all the fastening hardware out there but it makes up 99% of what I use in most of my designs. I wanted to share this universal CAD with my design team (the Waterloo Robotics Team) but I didn’t want our members thinking they could design with any screw imaginable since I had already established a standard inventory of screw sizes and lengths for the team. Thus, I brought colour into the design table and made the screw turn red whenever a non-standard length was used to remind members that they would need to custom order those screws.

I received a lot of positive feedback on the mini CAD library and decided to remove the red highlighting and publish the CAD to GrabCAD, a community where engineers and designers share their CAD models for free. I’ve downloaded many, many models from the GrabCAD community over the years so I figured it was about time I started giving back. Below is the demo video I made to accompany the CAD files on GrabCAD so that users who are unfamiliar with configurations and mate references can immediately know how to use the CAD models.

If you’d like to check out the GrabCAD project page to see how many people have downloaded the models so far, click here.

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