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Problems with Stripping Screws

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I keep having problems with nutplates and stop/lock nuts when using screws. They fit the threads so tight that when I try to screw them in the screw heads strip. It doesn't matter whether I hold the screwdriver and turn the nut or vice versa. The result is still the same. The screwdriver seems to fit well too, so I don't think that's it. Any ideas on how to prevent this? It sucks to pay $10 shipping for $3 worth of parts.
 
I suspect if you do a search on the forum, you will find numerous others have had the same issue.

Many have run a tap gently through the offending nut-plates (platenuts??) to relieve the friction. Caution not to overdo it, or the locking feature will be completely defeated.
 
I rub every screw going into a nutplate with a wax-like stick of boelube. Whenever possible, I spray LPS-2 on any exposed threads prior to trying to remove screws. If necessary I run a tap (not a bottom tap) part way thru the nutplate, but this usually isn’t needed. Sure about your screwdriver? I have a ‘magic’ screwdriver that removes screws cleanly when other screwdrivers won’t.
 
I keep having problems with nutplates and stop/lock nuts when using screws. They fit the threads so tight that when I try to screw them in the screw heads strip. It doesn't matter whether I hold the screwdriver and turn the nut or vice versa. The result is still the same. The screwdriver seems to fit well too, so I don't think that's it. Any ideas on how to prevent this? It sucks to pay $10 shipping for $3 worth of parts.

In addition to Bob's excellent advice, you might want to look into using Torx screws. There are lots of threads discussing them. They are much harder to strip. I've got a lot installed and I've probably "stripped" less than 5, usually because there was something in the screw that prevented the bit from fully seating, or I used the smaller bit (T10 instead of T15).

BTW, I also use ACF-50 or Boelube on my screws to prevent galling.
 
CorrosionX

I bought a bunch of those little clear condiment containers you get sauces for take out orders. But the hardware in, little squirt of corrosion X and the lid goes on. Shake it to coat and label for reassembly later. A little goes a long way. Definitely only for areas that you have already painted.
 
Or

Instead of a tap, which will defeat the self locking feature, get a few grade 8 cap screws. Run those in with some boelube. They will open up the nut plate but leave the locking feature.
 
The other end of the screw.

If you are using a PH2 screwdriver that may be some of your issue. There is the JIS (Japan Industrial Standard) that are designed to fit phillips head screws. The PH2 screw driver was designed to cam out of the screw before an assembly line worker could snap the screw. The JIS standard actually fits the phillips head and do not cam out. Once you get some JIS screw drivers you will throw the PH2 away. You can get bits to put into a driver in that standard too. I use Vessel and Wera. Another useful tool for stripped screws is the VAMPLIERS VT-001. Work like nothing else for getting a stripped screw off if it has a head.
 
I use the small impact driver to screw and unscrew and I find it doesn't strip the head as easily. The normal drill/driver tends to strip it more
 
I keep having problems with nutplates and stop/lock nuts when using screws. They fit the threads so tight that when I try to screw them in the screw heads strip. It doesn't matter whether I hold the screwdriver and turn the nut or vice versa. The result is still the same. The screwdriver seems to fit well too, so I don't think that's it. Any ideas on how to prevent this? It sucks to pay $10 shipping for $3 worth of parts.

If ordering small items from Aircraft Spruce check to see if postal service delivery is an option....the cost is often reasonable.
 
Boelube

Boelube - The stuff works for nut plates, without compromising them with a tap. One tube is enough to do your whole plane and still have enough to pass down to your grand children.
 
Like Tim said. JIS screwdrivers are one of the better tips I found on VAF.

I agree - since changing to JIS screwdrivers and bits a few years ago, all my old screwdrivers have been relegated to the junk drawer - not the toolbox. And they are no more expensive than Phillips - fidn them on any of the internet shopping sites … I think mine came mostly from McMaster.

Oh, and definitely invest in a few Allen-Head Cap screws as suggested by Rocketman - run them through the new nutplates with BoeLube, and your subsequent maintenance life will be much better.
 
Another good lube is beeswax.

A simple wax ring for seating a toilet is a great source, and enough beeswax to last a long time.
 
In addition to the JIS, I prefer cad plated screws over the stainless steel ones. Stainless seems to gall more and seize more often than cad plated ones.
 
Instead of a tap, which will defeat the self locking feature, get a few grade 8 cap screws. Run those in with some boelube. They will open up the nut plate but leave the locking feature.

I'd love to find out where you get Grade 8 cap screws in 8-32 or 10-32 threads! Socket head (Allen) cap screws are as hard or harder than SAE Grade 8 and will work nicely. But be sure to use a good hex wrench, or you can strip out the socket too.
 
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I'm in agreement, get a good JIS screwdriver, use Boelube or wax (toilet bowl ring will last a long time)
 
After running into a couple of nut plates that striped screw heads rather than accept a screw (in a very inconvenient location naturally) I made a practice of applying BoeLube to a screw and "exercising" each and every nutplate before riveting them into position on the plane. I also apply Boelube when reinstalling panels, etc. after inspection. As mentioned earlier, juditious use of an impact screwdriver or lower torque on electric screwdriver work well after you develop a sense for how much is enough.
 
I'd love to find out where you get Grade 8 cap screws in 8-32 or 10-32 threads! Socket head (Allen) cap screws are as hard or harder than SAE Grade 8 and will work nicely. But be sure to use a good hex wrench, or you can strip out the socket too.

Steve, I got some of the Allen cap screws from B&B Aircraft Supplies. I’m lucky to be semi local and can stop by the warehouse, they always seem to have what I need.
http://www.bandbaircraftsupplies.com/
 
NAS514

If you are having trouble with the supplied AN507 #6 screws stripping out, it’s because they only have a tensile strength of 55,000 psi, which is about half the tensile strength of the #8 screws supplied, which always struck me as odd. I changed all mine out to NAS514 screws which have a 125,000 psi tensile strength, so stripping heads out is no longer an issue.

Tom
RV-7
 
The CAD plated steel alloy AN509 aka MS24694 (ones with a S) are also 125 kpsi tensile where as the stainless steal AN509 (ones with a C) are 85 kpsi tensile. Both are better than using the 55kpsi AN507 aka MS24693 screws. CAD plated do not look as nice as the SS but much less likely to twisting off the head or stripping out the Phillips drive.
For those still building, I would suggest using #8 or larger as the #6 will always be problematic.
 
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I use candle wax. I doesn't flake off like Boelube. Just rub the screws on the candle and it sticks to the threads. Not FAA or ASTM approved.
 
What Screw size ?

I was taught to use #8s unless the choice is taken away from you.
#6 screws have the lowest root/OD ratio and have a reputation for failing on extraction simply from light corrosion.
 
Hi everyone! I'm back, and I wanted to let you know how I resolved the issue. I took all your input into consideration and did the following:
  1. I ordered anti-slip screwdriver bits from McGregor Tool
  2. I ordered cadmium plated screws from Aircraft Spruce
  3. I got some Tank Bond Liquid Grip in case the other two things didn't work

It turns out that I didn't need the Liquid Grip. The combination of cadmium plated screws and the anti-slip screwdriver bit seemed to correct the problem entirely. I was able to get the lock nuts onto the screws without stripping the screws. Thank you for all the input. I learned a lot from your feedback.
 
Stripped screws

Something that will help a screwdriver grip better if the screw head still has some bite to it is to take a small dab of valve grinder compound, dab a little on the screw. It will fill the gaps between the stripped screw and the screw driver..... I've taken out some stubborn screws using that.....:)
 
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