One of the halves of my favorite yoyos stripped today. I have an idea of what caused it, and hopefully some knowledgeable members will reply and confirm my suspicion.
So, one day the axle side with the allen slot got stuck in one half of the yoyo, and to avoid damaging the threads, I thought I would try wrapping the exposed axle with teflon tape, screwing the yoyo back together, then unscrewing it with the allen slot exposed. It worked!
Looking back at this, I think that I used way too much teflon tape. 6-7 wraps, at least. The first time screwing the yoyo back together after the teflon tape was applied was difficult, and took some effort. Could I have damaged the (female) threads enough here that they were on the verge of stripping?
The yoyo was made of 6016 aluminium.
PS: I don’t feel like mentioning the yoyo in question here is important. Talking about how a yoyo stripped tends to discredit the yoyo, when this was probably my fault.
So I use ton(ne)s of teflon tape with threads on a daily basis, and my opinion is that there is no way that tape inherently damages threads. However, tape makes it considerably easier to cross-thread. I cannot bear teflon taped yoyo threads, for exactly this reason. Once one starts using teflon tape, it is a slippery slope to stripping relatively healthy threads.
My guess is that when it was hard for you to screw back together it was because you were cross threading it. Practice of unscrewing the threads before screwing them back together usually aligns the threads properly to help avoid this.