I stripped the threads on my good scissor jack with an impact. I'd used an impact on it about 8 or so times before but I guess I didn't clean or oil the threads. On the jack up prior to stripping the threads, the impact really struggled to raise and lower the jack. So yeah, making sure the threads are decently clean and oiled is important.
Interesting. Thanks. Scissor jacks are often badly made, and good only for one or two emergency tyre chages. You wont find power tools which can deliver turning power at the low revs needed here at a DIY friendly price. So you'd need gearing of some sort. The "nut" half of the "nut and bolt" design of scissor jacks contains too few threads, so it's prone to failing. Clean thread yes. Lube? - only with gear oil etc as it can take the load. Wd40 not.
