Stripped screw removal.

[sparky7]

Im making this thread to make a compilation of techniques for removing stripped screws.

There is one method that i was once shown but have since forgotten, it involved cutting grooves in the top of the head and thats about all i can remember.

One method i often use is cutting a groove for a flat head but this is not ideal for corroded screws that are horribly stuck because it often snaps the head in half.

Aircraft mechanics im a new a&p and am looking forward to input...

 

[caper150]

Drill the head off and grab the rest with a set of vise grips, works for me.

 

[A_Pmech]

Cover the tip of your driver bit with rough valve grinding compound when you find a "stuck" machine screw BEFORE you strip it out. The valve grinding compound helps prevent cam-out. Then, using a speed handle push HARD and wiggle the handle clockwise and counter-clockwise using a short stroke and a moderate level of violence.

Failing that, sometimes it is possible to break a corroded machine screw loose by tightening it slightly using the undamaged clockwise drive flanks. THEN try to loosen it.

Don't be a cheap ***. Change your driver bits regularly.

 

[Crank1]

I generally use the drill the head off and use vise grips to remove the shank of the fastener if its possible.

Second to that would be drill the fastener and ez-out it...

That is after you fail at getting the fastener out with a new bit, then maybe some screw grab(pretty much valve grinding compound)

 

[hofferwood]

Cover the tip of your driver bit with rough valve grinding compound when you find a "stuck" machine screw BEFORE you strip it out. The valve grinding compound helps prevent cam-out. Then, using a speed handle push HARD and wiggle the handle clockwise and counter-clockwise using a short stroke and a moderate level of violence.

Failing that, sometimes it is possible to break a corroded machine screw loose by tightening it slightly using the undamaged clockwise drive flanks. THEN try to loosen it.

Don't be a cheap ***. Change your driver bits regularly.

How many screws or bolts, wouldn't have been broken if this procedure was followed? Then fer the tuff ones, if you have room, impact driver (the ones ya smack w/a hammer) tighten then loosen.
Chuck

 

[RTrac1]

I've welded a bolt to the stripped/broken fastener, then just put a wrench on it

 

[xJoey Dubsx]

I love my hammer impact screwdriver.

 

[Warrenator]

Get some left hand drill bits, keep them separate in original packaging and mark them with red sharpie. When you have tried the other techniques, failed, and now need to drill out the bolt, use the left hand drill. As the drill sinks in it will usually grab what's left of the bolt and spin it out. Oh, and use Kroil / PB Blaster / ATF and Acetone / Your Favorite Penetrating Oil as you drill.

 

[MScott]

Get rid of those damn Philips screws and use Robertsons. They almost never strip.

 

[creativecars]

Had one broken off flush in a head. Was going to drill it for an easy out and was using a 3/32" bit for a starter hole. I decided to do several across the bolt in a straight line, as close together as I could. I drilled them about 1/8" deep. Was then able to chisel a little then removed with a screwdriver.

 

[ourkid2000]

A&P mech's do not have the luxury of Robertsons......nor can you weld nuts onto screws on aircraft. We mainly use Phillips, Tri-wing, and Torque-set.

When I'm going at a load of screws on aircraft I follow a set routine. We have a very nice 1/4" IR impact wrench that I use first. Using a fresh bit and the occasional valve grind, I can do pretty well with it (if you can get some penetrating oil into the screw, do it but sometimes it just won't help). When the screw laughs at the impact I grab my 3/8" drive Snap On speed handle with the ********* knob on the end and put valve grinding compound on the bit and do exactly as A&P mentioned (wiggle back and forth while pressing very hard.....the knob on the speed handle helps immensely here). I've broke many a bit clean off without stripping the screw doing this so you can really put a lot of torque on the screw with this method.

If that doesn't work, I grab a sacrificial drill bit and drill a little bit out (to clean out the valve grinding compound). Then I grab a good drill bit, some Rapid Tap cutting fluid and start drilling down. Get the Snap On easy out in there and back the screw out.

If my "about to break the EZ out" alarm is going off I grab a bit the same size as the shank of the screw and drill the head. Grab an appropriate sized pin punch and snap the head off. If there's enough left after you've removed the panel to get on with vice grips you can remove it. Otherwise you may need to replace the anchor nut or whatever is holding that screw in. When that happens, I usually enlist some of my co-workers as I'm an Avionics Tech and I know my limits.

 

[kams1973]

I don't know the technical name for it, but it works with an air hammer. You put a 3/8dr phillips on it and buzz away. Of course, I know this wouldn't work on many light gen av airframes. We used to call them "knockers".

 

[jonny o]

Never touched a plane, but If I have enough room to lean on a drill, I simply use it as an impromptu light-duty impact with the "torque" setting low enough to rattle the screw.

I think the main reason it works is that I can put a lot of force on the bit, keeping it in a corroded screw.

 

[ourkid2000]

The screw knockers do work very well............if you're removing large structural panels and have lots of very large screws to take out, it's an essential tool to have nearby.

They rattle my soul though. They make a horrendous amount of noise.

 

[Quiksilver]

I think a lot of it has to do with the size of the screw that is being removed, as well as the reason that it is stuck.

Not to get off the original topic, thread corrosion is the main reason that I see for stripped screw heads. But, I also work a lot with aluminum castings with machine screws. If the threads are corroded enough that the screw won't come out, I like to use some penetrating oil with a little bit of heat from the torch if possible. It normally does not take much heat. If the threads are severely corroded this will almost always damage the threads in the aluminum. I like to use a thread repair kit if I see any damage in aluminum.

Didn't mean to be so specific about aluminum, but the technique could apply to almost any material.

 

[sparky7]

Just this morning i had to remove the fuel tank covers on a cessna 150 and 4-5 of the screws wouldnt come out and the heads snapped off while using the extractors. i ended up drilling them out and then running a tap down through the nut plates which actually pushes the remenants of the screw out the back side of the plate most of the time. this works well but not all the time...

I am just sick of using rivnuts through the spar when all else fails it seems half-assed to me.

 

[mbatarga]

Get rid of those damn Philips screws and use Robertsons. They almost never strip.

It figures a Canadian would have to bring that up!

 

[Mr_Rich]

Maybe if you take them to Windsor?

 

[csargents1546]

Sometimes the stud on exhaust manifold break below the surface, take and mark the center, drill a hole and use a square screw extractor, the ones I use are made by proto. works great. If you can get ahold of it with vise grips, heat is also a good trick, heat the threaded part and work the stud back and forth.

 

[stopdroplol]

I think a lot of it has to do with the size of the screw that is being removed, as well as the reason that it is stuck.

Not to get off the original topic, thread corrosion is the main reason that I see for stripped screw heads. But, I also work a lot with aluminum castings with machine screws. If the threads are corroded enough that the screw won't come out, I like to use some penetrating oil with a little bit of heat from the torch if possible. It normally does not take much heat. If the threads are severely corroded this will almost always damage the threads in the aluminum. I like to use a thread repair kit if I see any damage in aluminum.

Didn't mean to be so specific about aluminum, but the technique could apply to almost any material.

This is good advice.

I'd add, that if you feel the corrosion dragging in the thread, like it doesn't want to come out, then re-tighten in and start over. Do this repeatedly and hopefully it will eventually want to come out easily. Basically you don't want to force the screw through the corrosion, rather break it up and disperse it. Probably works about 60% of the time.

 

[57210]

We used to have a tool that we put in a rivet gun that held an apex bit and had a handle at a right angle. You use the rivet gun to keep the bit from camping out while putting rotational force to turn the screw with the handle. Sorry no pictures

 

[ourkid2000]

That's referred to as the "screw knocker".

 

[neverenoughtools]

Get rid of those damn Philips screws and use Robertsons. They almost never strip.

Gotta love this Canadian fastener " EH "

 

[spp2000]

These are my best friends, in case of stripped/broken screw, stud, bolt removal.

The first in an EXCELLENT screw plier made in Japan, very hard steel (HRC56) with a frontal grip. This is a must for me, also because it is not dedicated tool but you can use it as a normal plier:

http://www.engineer.jp/en/products/pz55_56e.html
It is not cheap but I'm quite sure that it will do a lot of works!

An impact driver:

with some adapters you can use any bit, not only the four big bits included.

A stud remover, useful also to remove some stripped screw, because it has a good frontal grip; the more you rotate it ccw (to lose the screw), the more it closes its jaws:

To complete my review, these are some extractors, if you can drill the broken screws:

A set of nut splitters, that broke the nut without damaging the threads of the screw:

and in case of rusted/gripped screws you can use a butane torch to heat the part and then a hammer to broke the rust inside, WD40 or a little pipe wrench:

In some cases, I re-make the incision on the head, with a saw or a Dremel, to use a normal screwdriver.
With these tools I have ever had the best on the broken screws!!!
Sorry for my english!!
Carlo