Screw extractor - Pilot hole size and which size extractor to use

mickyd · Post by **mickyd** » Tue Dec 01, 2009 2:01 pm

heathicus wrote:I would think the advantage would be a more precise and targeted application of the heat with a soldering iron. Instead of the screw and everything around it getting hot equally, the screw would heat at a different rate than the surrounding material since the heat would have to travel through the screw. Maybe?

I was going with heating the whole area since the thermal expansion rate of aluminum is greater than the steel screw.

JPG · Post by **JPG** » Tue Dec 01, 2009 2:09 pm

mickyd wrote:I sure wish they provided a maximum recommended torque to safely apply to those extractors. On my #8 (.164") screws, I used the #2 extractor with a 7/64" (.109") pre-drill. #2 extractor covers a screw range of 5/32" - 7/32" (.156" - .219") (screw sizes #8 [.164"] thru #12 [.216"]).

The broken fasteners wouldn't budge and I was hesitant to snap the extractor. Then I'd need to get a screw extractor extractor!!!:p I timidly applied heat with a propane torch but that didn't help.

Any suggestions?

HAVE YOU APPLIED KEROSENE YET! Be Patient , it does work(eventually). Vibration(banging) helps. I am guessing steel screws in cast iron???? <<< I missed the earlier post re they be in aluminum.

See later post re cutting torch.(I know you aren't likely to have one, but steel fabricators usually do(yer pieces ARE portable!)).

JPG · Post by **JPG** » Tue Dec 01, 2009 2:27 pm

mickyd wrote: And jpg...your point on the demolition guru...you need to take the inverse of it...a structural engineer won't know how to do demolition. You flipped the example I gave around.
My point(which whizzed past yer noggin) was that a demolition 'expert' who intends to implode a structure had better know a LOT about structural engineering since they typically really really really weaken the structure prior ot 'lighting the fuse' Perhaps I did 'flip' your example!
Now tell me what I need to do to get those broken fasteners out of my ER's work and extension tables without snapping my extractor. I didn't get one pilot holes centered enough to drill out furthur and chase it with a tap.

Steel screw in aluminum. I was serious regarding an acelelylene cutting torch!

Step one - heat up the steel screw to red hot. The rust will help minimize heat transfer to the aluminum base.

Step two - When red(maybe a little warmer) hit the oxygen valve(causes rapid oxidation of the red hot steel and walla! the bolt is among the 'missing'!

Step three - allow to cool and chase the threads! Fini

De Nada!

BTW That is how us 'steel fabricators/welders' handled taps broken off in structural steel!

nuhobby · Post by **nuhobby** » Tue Dec 01, 2009 2:46 pm

I once read a fellow's memoir of a Tractor restoration. In some cases a rusted-screw could be dislodged by using all of your methods .... PLUS, try tightening it a bit before trying to remove it.

mickyd · Post by **mickyd** » Tue Dec 01, 2009 2:48 pm

JPG40504 wrote:Steel screw in aluminum. I was serious regarding an acelelylene cutting torch!

Step one - heat up the steel screw to red hot. The rust will help minimize heat transfer to the aluminum base.

Step two - When red(maybe a little warmer) hit the oxygen valve(causes rapid oxidation of the red hot steel and walla! the bolt is among the 'missing'!

Step three - allow to cool and chase the threads! Fini

De Nada!

BTW That is how us 'steel fabricators/welders' handled taps broken off in structural steel!

I did think you were kidding re cutting torch. Hum!!

Your going to keeping pushing kerosene on me until I try it right? OK, I'll do it. How do you suggest I dispose of it when done? Use the acetylene touch?:eek:

JPG · Post by **JPG** » Tue Dec 01, 2009 3:07 pm

mickyd wrote:I did think you were kidding re cutting torch. Hum!!

Your going to keeping pushing kerosene on me until I try it right? OK, I'll do it. How do you suggest I dispose of it when done? Use the acetylene touch?:eek:

A Torch might work better!

Geez you Ca NUTS! There isn't going to be anything to 'properly' dispose of after it migrates all over your part! It is this tenacious migrating attribute that helps it separate rusted/corroded stuff! I have not tried kroil to know if it works better. The K1 has always worked, however the introduction of different oxides(corrosion) may be working against this. I am surprised and curious why Bill Mayo extols Kroil's virtues when you have not had similar experiences. Maybe he is waiting longer? The Kerosene does take a while to be effective. Btw I think kerosene is an important ingredient in KRoil! (That is spelled "petroleum distillate")

Good luck tightening those broken screws 'first'!:D

Last resort b4 a trip to a 'torch'. Impact wrench applied to extractor(This greatly increases the risk of fracture). I am referring to the smack it with a hammer type having square drive on its 'output' shaft. This allows severity of smacking control with small attempts(distance). It provides both the torque and 'vibration'(shock force).

mickyd · Post by **mickyd** » Wed Dec 02, 2009 3:02 pm

JPG40504 wrote:A Torch might work better!
............

Last resort b4 a trip to a 'torch'. Impact wrench applied to extractor(This greatly increases the risk of fracture). I am referring to the smack it with a hammer type having square drive on its 'output' shaft. This allows severity of smacking control with small attempts(distance). It provides both the torque and 'vibration'(shock force).

Not gutsy enough to try the impact wrench (smack with hammer style), not to mention can't envision how to go from the 3/8" square 'output' drive of the impact wrench down to ~1/8" square 'input' drive of the extractor

. Even if I could , I'd have no way of judging how much torque is being applied to the extractor. I'll only know when I applied too much

and don't EVEN want that to happen.

I have another option I just thought of. I might try this prior to the time consuming soak in solvent. Since my pilot hole is already off center by ~1/32", I can increase the pilot hole diameter until the hole just breaks thru into the threaded hole. It will booger up the threads in that localized area but that won't cause a functional problem. Next step would be using a Dremel tool with a high speed cutting bit to grind away the other side, 180° from the break thru from the drill bit. That's it....that's my plan....for now anyway.

a1gutterman · Post by **a1gutterman** » Wed Dec 02, 2009 11:48 pm

lv2wdwrk wrote:After heating, what about LIGHTLY taping with a hammer and punch or something similar. We used this process growing up on the farm and had a bolt that would not come out.

I've done some light taping with a broad blade, but never a hammer...hum...does the hammer head spread the mud better then the claw?

Ed in Tampa · Post by **Ed in Tampa** » Thu Dec 03, 2009 12:26 am

If you got a steel screw in aluminum I don't think you will ever get it out. My mower deck spindles were that exact setup. I broke every head off the bolts and then tried to get the studs out.

Finally gave up and bought new spindles. Then i could really play with the old ones. 20-20 hindsight I should have drilled the studs, and used bolts and nuts to hold the spindles in. In any case I had the new spindles so I was free to dissect the old ones. Cut into the spindles so I could have exposed bolt. Even with the hole cut in half and bolt stud in half I couldn't remove the steel both from the aluminum. I'm convinced it was there for eternity.

I would drill them out, use a torch and burn them out but I would never never try to use a screw extractor on them. It would be a total waste of time. I don't care how long you soaked the thing.

mickyd · Post by **mickyd** » Thu Dec 03, 2009 8:39 am

Well Ed, that's a totally.......discouraging post!!:( However, it will make me feel better if I have similar results. The easiest thing to do would be to just go out and buy both a work and extension table but that just isn't my nature. I'll keep trying. Good for the brain, good for skill improvement. Appreciate you sharing your experience though.

I'm sure you guys have seen enough snapped screws / bolts in your days but since this post has absolutely NO PICS yet, here's what I'm facing. The views are looking down the length of the extension table.
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front (outside)
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front (inside)
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