Screw extractor

Do you prefer a spiral or straight flute extractor? I need to extract an aluminum 3/4” npt fitting from an aluminum manifold that someone sheared off. I do not have any experience with these so since I have an option, I thought I would ask. Seems like size 7 is what I need. Thanks in advance for the help.

Amazing what you can find on You Tube

How to Use a Screw Extractor | Remove snapped off bolt from engine - YouTube

I also like these for stripped screws

How to remove a damaged screw with a broken screw extractor - YouTube

There are "nipple wrenches" made for pipe. They fit inside and jam against the inside diameter.

https://www.familyhandyman.com/wp-content/uploads/2017/06/FH14MAY_PIPWRN_01-2.jpg

That may or may not work. Aluminum pipe in aluminum manifold, unless a good deal of pipe dope was used, those parts may be one part now....Aluminum likes to gall, and it takes a good bit of pipe dope or other material to keep them from welding together as the joint is tightened.

Often you can find a nice piece of square stock with crisp edges that can be tapped into the remains of the fitting and then using a crescent wrench, unscrewed. This method gives you 4 points of contact and precludes buying a big old easy out for a single job.

Stuart

I had a good set if straight flute that worked real well. I used good spiral also with good results. Strait flute is better. IMHO
If a bolt shears its locked in tight. You should work the sheared off screw/bolt with penetrating oil and heat if it can be heated. Extractors will break. I try to give some sharp blows to the broken bolt taking care not to damage anything. Bolts have clearances in the threads. Oil and heat help loosen the rust that filled the threads. An easy out will seldom remove a broken bolt without working the broken bolt first. Patients
You can sharpen an old punch to a small chisel point and tap in the counter clockwise [loosening] direction also.

My point is don't expect more from the easy out than the bolt/pipe that broke. You will brake the tool.

I like the strait flute because they seem to wedge in better. I give it a little tap on the end before I start turning.
Asked straight or spiral and the guy writes a book

I really like the tool in the link that Jst gave. [above]

You can also try to find a chisel that’ll drive into the broken fitting and turn it out with a crescent wrench. It’s worked well for me on all but the most corroded fittings.


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You may want to start thinking about how you'd fixture the part to mill and rethread the part, as there's a decent chance you'll have to go that direction in the end.

You don't need lots of thread engagement in low-pressure Al mates, it might actually help with removal to have a slightly "open" thread and use the right sealing compound, as it should make the next removal easier, with less surface area to corrode together.

Straight flutes don't unduly expand the shell of the drilled-out fastener, plus they let you twist both ways if you need to 'work' it a bit. Gets my vote.

If I had a £1 for every broken screw I've had to get out I'd be rich. Normally I'd use the spiral type of screw extractor. Getting broken screws out of brass or cast iron I'd say I had a 90% success rate, out of steel maybe 50%. Of course the broken screw had to come out so you'd use other methods when the screw extractors failed. Spark eroder etc. Do NOT use excessive force and break the extractor, if you do you have major problems.

Somebody gave me a " Proto " set of straight tapered screw extractors, they were useless, my success rate with those was 0 % !

I shouldn't say this and you do this at you own risk but in emergencies I've used a square file as a screw extractor. Tap it into the drilled hole lightly and turn VERY carefully. Big square files are good for getting out small bore broken pipes. Wear eye protection.

If the screws were sheared off IE easy to turn but awkward to get at I've ground a drill to cut backwards and run the drill press in reverse.

Regards Tyrone.

Small block Chevy? If so that fitting is a piece of shit and I don’t think it is truly aluminum. Fought many of them in the shop. A few had to be slotted and chiseled out. Have a pipe tap handy to repair the threads in the manifold. Our tool trucks( Matco and Snap-On and Cornwell) even started stocking the taps..
Generous coating of pipe dope with Teflon going together.
Joe

And there is always the left hand drill bit (provided fitting is RH thread).

Hmmm, aluminum to aluminum pipe thread, At best you are probably going to tear out some thread.

Straight extractor (the spiral ones expand the piece you are trying to remove),

Heat (electric heat gun),

Penetrant - I suggest paraffin, melted in with the heat gun,

Some kind of controlled impact force - might be a small impact gun turned down low or even have an assistant tap gently and rapidly straight down while you carefully apply torque.

Even with heat if you just start twisting it's likely to either ream out the fitting or rip out the threads.

Take a die grinder and cut as close as you dare through the fitting without eating into the threads. Use a hammer and punch and collapse the fitting so the threads release. You may have to work all the way around the fitting to get it loose until you can remove it with pliers. This is the method I use to get frozen stainless exhaust inserts out of an aviation engine at annual every year. As said above, run a tap in to straighten things up and should be good to go.

Just drill the motherfucker out and put in a helicoil.

I have to agree with a left hand drill. I keep a limited set of left hand drills for small, broken screws and they have never failed me on screws of 1/4" or smaller. But I haven't any experience with larger sizes or with pipe which would be hollow.

I see the following considerations. First, since the pipe fitting is hollow, you probably do not need to drill it out first. If you use a spiral extractor then it will try to dig in and that may expand the aluminum pipe, making it stuck even harder. On the other hand, a straight sided one will need to be tapped in and that also may tend to expand the pipe. Either way you are taking a chance.

On the other hand, a two flute, left hand drill will be hard to control in the already opening of the pipe. If I had my druthers, I would like to have a four or even a five flute, left hand drill. That would tend to stay centered in the existing hole better. I guess a three flute drill would be better than a two flute one. In any case there should be a firm, solid set-up between the drill and the manifold.

A thought just occurred to me. Perhaps this could be done on a mill which would provide the firm set-up and a left hand milling cutter could be used to drill out and perhaps coax the pipe to unscrew. A slightly dull milling cutter may aid in that coaxing.

morsetaper2 said:

And there is always the left hand drill bit (provided fitting is RH thread).

Click to expand...

I have never had good luck with screw extractors.
Quite simply I own a lot of them and simply hate the things with a passion.
I'd say straight a bit luck better than spirals but in the case with soft materials they both tend to expand and lock the part you are trying to free.
Both will work better with a tapered hole to bite in but that's a special drill bit. (which should come with such kits and bits but does not)

I do however have lots of drill bits sizes and the ability to toss one in the centerless and make any size I desire.
So my technique here ( very different than removing tool-holder screws at repair time) is to start drilling it out just over the inside the hole size.
Then steeping up and drilling again, and one step up in size and again,.. watching for the crests of the base parts threads to appear.
You will not be drilling central to the threads themselves so this happens on one side.
You probably also will not be true square so you hit top or bottom first and have to go back and do some sideways monkeying with the hand drill to open up a full side.
Once this happens you can use a punch to "collapse" the offending part as talked about above.
None of this is pretty and it is a hack but AL/AL or AL/Pot metal does not like to come apart if it has seen years of use.

If it sheared at removal it does not want to come out and is seized in the threads.
Very different than broke from over-tightening or sideways loads from a crash.
No "extractor" bit will be as strong in force as the original head. Heat might reduce the torque needed or break the bond if applied to the right area.

Helicoil is the quick way but you have to buy an entire kit and sometimes there are sealing problems.

You can also setup in a B-port, mill flat to the surface, put a microscope in the spindle to pick up exact and bore to the thread inner.
Then pick out the slivers. I've done that too. Very time consuming but on a high value part.......

I do toolholder screws all day long with a left hand spade but thinking this problem won't response well or at all to this easy way out.
The head evidently broke off, the threads do not want to give up easily.
Bob

The manifold is threaded for 3/4” pipe threads. It would need a huge left hand drill to touch metal and I’ve never seen a pipe thread helicoil.
A pipe nipple inside wrench would possibly work if he could find one. My experience is to collapse the nipple somehow and dress the hole. Add copious pipe dope and move on.
Joe

Aluminum pipe should collapse well, if any is sticking out. If it is all buried that's a different problem.

Agree, helicoil for pressure piping? There might be one, though I've never heard of it. Usually mill out the old, to the thread crests, then pick out the thread remains. Possibly a reamer made for NPT would be useful to get the remains cut down to the crests following the taper.

You can't screw around much, if the pipe is supposed to seal, you may need the profile to be pretty decent. Even pipe dope has it's limits, and cannot always be used. If it is NPT, probably OK, but the fancy sealing threads will resent being damaged, and leak.

The only thing I hate worse than Easy-outs is Walton tap extractors.

NPT Thread Insert Kits - Thread Insert - Grainger Industrial Supply
Helicoils should be secured with locktite or similar anyway so go for it.

Aluminum in Aluminum I would not have much hop. A screw extractor is a screw expander. If you want it out you MIGHT ( but not likely) get it with a left hand tap that fits the ID.