Nutplates

[DeltaVee47]

I am nearly finished with the FF kit so you might think I should be long over this but my frustration with nuplates just boiled over today. What am I missing here? It?s nearly impossible to get the very soft headed AN screws to screw into the nutplates without stripping. Why is this so hard? Is there a technique for this that I am missing? Grrrrr! I need a Tylenol.
Thanks for listening
Greg Beckner
N557GB
140366

[MS1095]

Coat the screws sparingly with BoeLube. You will be amazed at how easy they thread and will stop stripping heads.

https://www.aircraftspruce.com/catal...clickkey=11321

[DaveO]

I have had better success with Bolube on the screws before use.

[Aluminum]

Originally Posted by DeltaVee47

I am nearly finished with the FF kit so you might think I should be long over this but my frustration with nuplates just boiled over today. What am I missing here? It?s nearly impossible to get the very soft headed AN screws to screw into the nutplates without stripping. Why is this so hard? Is there a technique for this that I am missing? Grrrrr! I need a Tylenol.
Thanks for listening
Greg Beckner
N557GB
140366

Run a tap through the nutplate after installation.

Depending on your riveting technique, sometimes the alignment with the hole can be slightly off, resulting in interference at the nominal thread axis. There can also be some manufacturing variability of the nutplates themselves, but all the ones I received from Van's recently have had smooth action.

[sahrens]

One technique is to run an appropriate sized tap down into the nutplate. Of course that does reduce some of the effectiveness of the nutplate. In the RV-7 instructions Vans mentions this technique. If my memory is correct it is mentioned when installing the nutplates for the seat panels.

Another technique is putting a little oil on the screw threads and running it down with an electric screwdriver/drill and backing it out. I have also found that sometimes the nutplate is not fully aligned with the hole in the sheet metal and the screw is binding on the sheet metal. A small jeweler file can fix this issue.

I'm sure you will get other suggestions as well.

[Ironflight]

As suggested above, Boelube is a good answer.

Defeating the locking feature of the nutplates by running a tap through them defeats the designer’s purpose in putting a locking nutplate there. In some cases, this is OK - but only in some cases. If you do it indiscriminately, without understanding how aircraft are designed, you’re really butchering the project.

[lr172]

Another thing is that you must increase the downward pressure on the screwdriver proportionately as the resistence to turning increases. I learned some years ago to use a phillips bit on a ratchet for loosening really tight phillips screws. It makes it much eaier to get enough downward force, as you are using one hand to push down and another to turn. You might try that when tightening the first screw in a nut plate.

Larry

[Aluminum]

Originally Posted by Ironflight

Defeating the locking feature of the nutplates by running a tap through them defeats the designer?s purpose in putting a locking nutplate there. In some cases, this is OK - but only in some cases. If you do it indiscriminately, without understanding how aircraft are designed, you?re really butchering the project.

Nutplates are not normally used for joints that require the full bolt strength. They do not perform as well as a regular nut whose threads come up to the material. An easy way to tell is if the bolt isn't torqued to spec, as is the case with all phillips head screws holding panels and such. These are what the OP was having trouble with, if I understood well.

It's not the locking of the nutplate that keeps the bolt from turning, that's normally only a small part of the total friction. The locking action can slow down nuisance unscrewing if the assembly wants to vibrate loose, and only after the nominal clamping friction has been defeated. A better way to accomplish the same is with loctite, for instance on the spinner and other highly cycled places.

Lubrication doesn't help if there is physical interference between the misaligned hole and the bolt. A thou of misalignment is practically impossible to see, but will greatly increase friction and cause galling and stripping. Running a tap takes care of this and doesn't damage the nutplate.

It is safe to run a tap through almost all nutplates.

[pa38112]

Originally Posted by Aluminum

Nutplates are not normally used for joints that require the full bolt strength. They do not perform as well as a regular nut whose threads come up to the material. An easy way to tell is if the bolt isn't torqued to spec, as is the case with all phillips head screws holding panels and such. These are what the OP was having trouble with, if I understood well.

It's not the locking of the nutplate that keeps the bolt from turning, that's normally only a small part of the total friction. The locking action can slow down nuisance unscrewing if the assembly wants to vibrate loose, and only after the nominal clamping friction has been defeated. A better way to accomplish the same is with loctite, for instance on the spinner and other highly cycled places.

Lubrication doesn't help if there is physical interference between the misaligned hole and the bolt. A thou of misalignment is practically impossible to see, but will greatly increase friction and cause galling and stripping. Running a tap takes care of this and doesn't damage the nutplate.

It is safe to run a tap through almost all nutplates.

Actually, the reason a nut-plate has a deformed thread is to prevent the bolt from backing out due to vibration in parts that, by design, can not achieve proper thread pre-load. For example when attaching fiberglass or thin sheet metal, where torqueing to spec will likely crack or deform the part. It has nothing at all to do with the joint strength. Running a tap through it damages the nut plate's locking feature. Do you really want to use loctite on every screw every time you take off your wheel pants? Lubrication absolutely reduces the running friction.

[JDA_BTR]

I got a stick of beeswax from the local beekeeper. Rub the end of the screw on it and works great.