I used cross nuts exclusively for my first build
and had great success with them. But lurking on the forum, I noticed many people are struggling with "spinners". I spent HOURS on forums trying to find what's the latest consensus on threaded inserts, but no luck. It's still a endless debate. It's hard to thrust someone's opinion when there is no data to back up their claim...
So I went ahead and attempted to QUANTIFY spinout resistance torque of CrossNuts and RivetNuts
. In addition, I tested a few "hacks" often mentioned in forums: regular washer, split lock washer, tooth lock washer, CA glue, Red LocTite, and J-B Weld:
- I didn't use "fixed material" between the insert and the bolt (which creates friction on the insert's head and increases spinout torque). That intentional, my goal wasn't to quantity the "real-world" spinout torque. I just wanted to compare different inserts/hardware spinout resistance, so I took the "fixed-material" out of the equation (which was one more variable).
- My test sheet is 0.032" thick and holes are 0.364" to simulate standard holes on the Transit.
- The spinout torque was recorded with a digital torque adapter.
- Rivet Nuts (alone) and Cross Nuts (with tooth lock washer) gave the best results
. In fact, the spinout torque was beyond the recommended torque for a 1/4 bolt (grade 5) and I was able to shear a few bolts (or damage the crossnut/rivnut).
- CrossNuts (without hardware) spinout torque varies a lot, and it's hard to obtain repeatable results.
- The tooth lock washer increases the spinout torque a lot, and also helps installing the crossnut straight and flush with the mating surface. Win-win.
- Rivet Nuts installation is very predictable and repeatable.
- I'll probably prioritize Rivet Nuts
on my next build, but still keep a few Cross Nuts handy for the oversized or oddly shaped holes (hex, square).
This is a short version of what you'll find here: https://faroutride.com/threaded-inserts/
In the link above I also got a 360° virtual tour showing ALL sizes/locations of threaded inserts in the Transit cargo area
. I'm pretty proud of that and it should be very handy!
It might not be a huge revelation, but at least I've got data to back up my decision for my upcoming build!
OK I'm done here, up to the next project!