Nylon nuts and repeated removal.

[ADK-Flyer]

I’m getting ready to start my build and I’ve been watching YouTube videos of other people’s builds. One thing I’ve noticed that bugs me is that while going though the build I’ve noticed that some assemblies like the horizontal stab, control assembly and others seem to come in and out a few times. I’m curious what are most other builders doing when assembling. Are you fully torquing each assembly every time? The way I’ve always treated nylon nuts is the first torque down is the best one and after a few removal and reinstalls it is really a non locking nut at that point. I was curious if some are just going finger tight if they know the assembly is coming back out again?

[Dave S]

ADK,

What many of us have done in our builds is get a bunch of cheap SAE fine thread nuts, put the nylocks aside and use the non locking cheap nuts till we are done with the normal fitting re-trials and install the nylocks when (we think!) we are done with fitting. In trial assemblies, I don't believe a final torque setting is necessary till the nylocks go in. Others may see that differently.

[MFleming]

The rule of thumb is, if you can’t install the nut by hand, it’s still good as a locking nut.
BUT, I use a stack of washers superglued together for fit-up work so I’m not wearing out the nuts.

[ADK-Flyer]

ADK,

What many of us have done in our builds is get a bunch of cheap SAE fine thread nuts, put the nylocks aside and use the non locking cheap nuts till we are done with the normal fitting re-trials and install the nylocks when (we think!) we are done with fitting. In trial assemblies, I don't believe a final torque setting is necessary till the nylocks go in. Others may see that differently.

I think buying the cheap nuts for mock up is a good idea and I believe I already have some around here.

[MFleming]

I think buying the cheap nuts for mock up is a good idea and I believe I already have some around here.

The danger of using hardware store nuts, is they’re likely to end up on the build permanently.

[ADK-Flyer]

The danger of using hardware store nuts, is they’re likely to end up on the build permanently.

Yeah I could see that. For me I would only use non nyloc nuts from the hardware store so they are obvious or even mark them with a red marker. Definitely keeping track of the areas that the proper hardware needs to be installed for final assembly and putting the proper hardware for that area in a ziplock bag or something. I did have the same thought though.

[rv9ralph]

I have been using castlelated nuts AN310-? during the build for things that have to be installed and removed during the process.

[patrick.hvac]

I'm in favor of cheap assembly hardware for anything that will come back apart.
Final assembly of any part gets torqued and striped. Full hardware inspection before closing anything and for final.
There are some parts that went on and off a hundred times (for me), why waste the nyloc.
I also used the safety pin style cotters for anything castellated that was temporary assembly.
Do what works for you but don't re-use nyloc hardware.

[Av8r3400]

The danger of using hardware store nuts, is they’re likely to end up on the build permanently.

Unless you are using grade 8 hardware store nutz, they will be silver in color instead of the gold color of the aircraft grade AN hardware.

[jiott]

I found that for most sizes the number of nyloc nuts supplied in the kit was way more than needed. So I went ahead and used the correct nyloc nuts for all my fitting in and out (used the same nut each time), then when it was time for final assembly and torque I used a brand new nut. If the part had only been removed once or twice I did not replace the nut unless it was a real critical structural part. When I got all done I still had nuts left over. Of course every nut got a red or orange lacquer mark (Torque Seal) after final assembly torque. As a point of interest, in 10+ years, 1300 hours, I have never had a single nut or screw vibrate loose anywhere on my Kitfox or Rotax 912. I think this speaks to the smoothness of the Rotax engines.