Nylon lock nuts

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Forum topic by yinzer posted 03-06-2017 03:21 PM 808 views 0 times favorited 7 replies Add to Favorites Watch
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7 posts in 1950 days

03-06-2017 03:21 PM

Topic tags/keywords: question

I am sure that I probably should know about this, given the fact that I am as old as I am but I don’t. I am making a router lift that employs a 3/4 – 10 tpi allthread. I thought I would avoid using jamming 2 nuts to lock in the bolt and get a couple of nyloc nuts. I have run across some of these in my life although much smaller than 3/4 ”. And they were a slight bother but not too much. Now, trying to thread this nut onto the 3/4 in bolt is brutal.
Before I just give up and use either loctite or jam nuts I thought I would see if I am missing some step to make the initial use of this type hardware feasible.

7 replies so far

View johnstoneb's profile


3011 posts in 2316 days

#1 posted 03-06-2017 03:32 PM

the bigger the nyloc nut the harder they are to get on. I always used an air impact wrench. You night not want to do that on something as light weight as a router lift.

-- Bruce, Boise, ID

View Lazyman's profile


2517 posts in 1531 days

#2 posted 03-06-2017 03:54 PM

Are you sure that they are the same thread pattern as the allthread? Examine the thread after you tighten it down and make sure it didn’t basically cut new threads. If not, I think that they may actually make the thread a little tight on purpose so that they don’t wear out too quickly and stay tight. They should loosen up with use which might be a reason not to use them.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Bill_Steele's profile


414 posts in 1875 days

#3 posted 03-06-2017 04:13 PM

I agree with Bruce and Nathan. It think you should verify that the nut has the correct thread pitch for the allthread you selected. I believe 3/4” hardware comes in course (10 tpi) and fine (16 tpi) configurations. Could you possibly have 1/2-10 ACME or 3/4-6 ACME?

Nyloc nuts are a little bit harder to tighten. I recently finished a project where I used 1/2” nyloc nuts. I was able to tighten the nuts with a combination wrench and I’m not very strong. If you are really bearing down and it’s not moving—I think something else is wrong.

View yinzer's profile


7 posts in 1950 days

#4 posted 03-06-2017 04:33 PM

It is the correct thread. The nut does go on but I don’t even want to think about threading it up about an inch or two. I thought there might be some step to make it easier to thread it on the first time.

View MrRon's profile


5086 posts in 3387 days

#5 posted 03-07-2017 06:39 PM

If it wasn’t hard to install, it wouldn’t serve the purpose of a lock nut. Once installed, it shouldn’t be removed unnecessarily. After a few cycles of removal/re-installation, the nut will lose some of it’s locking properties. On military projects, lock nuts are permitted to be re-used only once on non-critical applications, while re-use is prohibited on critical use. When absolute security is needed, nylon lock nuts cannot be used. In such a situation, fasteners have to be wired together. A critical situation would be when loss of a fastener would mean immediate failure, like an engine on an airplane. I know this is more information than you ask, but I like to pass on as much information as I can.

View dschlic1's profile


442 posts in 2113 days

#6 posted 03-07-2017 07:03 PM

Are you making the Woodsmith router lift? I did the same. I ended up using a normal nut, drilled a #7 hole in one side and tapped it for a 1/4-20 screw. Easier and I KNOW that that nut will not be turning!

View HokieKen's profile


6266 posts in 1282 days

#7 posted 03-07-2017 08:01 PM

MrRon hit the nail on the head. If you have a tap the same size, you can run it through to reduce the force of the locking plug but, that kind of defeats the purpose. I think I’d use a couple jam nuts or drill and tap for a set screw like dschlic1 did.

-- Kenny, SW VA, Go Hokies!!!

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