Good ideas for screw extraction, please

[cranetruck]

Well, as usual you guys are the greatest! Will Wagner is going to lend me a set of LH bits for the project (saves me a lot of driving and checking McMasters, they are not cheap either).
I think that using LH bits is the smartest way to go.

As far as making this a "sticky", see Kenny, he has the authority and you know me, there will be more pictures to complete the thread.

 

[wdbtchr]

I've never had much success with bole extractors of any type. Seems like the bolt splits and the extractor winds up acting like a wedge tightening the bolt even more. If the bolt extends throught the pump and you have room to work weld the nut on the back and screw it out that way. I did that on lug bolts broken off flush on my backhoe. The boles stuck out about 3'8" inside the flange. I screwed nuts on the back side and with a stick welder welded them and removed them from the back of the axle flange.

 

[Barrman]

My students break about 1 bolt off a week here in my class. You name the brand of extractor, and we have broken it off in the drilled out bolt. Then the problem is tougher because the extractor is normally stronger than the broken bolt and the drill bit needed to git it out of the way.

Left had drill bits, chisel/hammer and the weld a nut to the end of the bolt are our stand by methods now. I am looking for a left hand tap set in all the usual sizes. (1/4, 5/16,3/8, etc..) Then I will try to find a single left hand bolt for each of those sizes. Then I can use the left hand tap/bolt that is one or two sizes smaller than the broken fastener. I figure between the left hand drill, left hand tap and left hand bolt, it will become the ultimate solution to students that still have to learn the difference between 12 inch pounds and gorilla tight.

 

[derby]

Ok,If all of the above fail. What about drill and tap to a 7/16"-3/8" and use it that way? Just my out of the box thinking.Or drill ,tap,install bolt with red lock tight,let dry and back out? I have seen red locktight pull the threads out of cast iorn! Good luck

 

[K10A]

I was a machinist for several years and I HATE ez outs . Think about you drill the bolt, drive in a Tapered tool that expands the bolt and keeps it tight in the threads, Dumb. I used all the above methods plus one. For really rusted goobered up junk I would drill it out as big as possible the use a dremel or small die grinder and cut it into 4 sections then collapse it with a chisel. - A

 

[wpzimmer]

Broken bolts and worse

I have to deal with this sort of thing fairly frequently. Wax and penetrants can be a big help. Heat is also usually your friend, especially with steel bolts in aluminum parts. Left handed drills and taps and an assortment of left handed bolts can be very useful . The bolts can often be found at a good hardware store. I have found frequently that the broken bolt extractors will expand the broken bolt in its hole wedging it in even tighter. Best to ues one size smaller than recommended to avoid expanding the end of the bolt if possible.

One little trick I learned when the usual methods have failed me is to drill out the offending part with a carbide drill. No need to buy the expensive ones from the machine tool catalogs. I buy the cheap masonry bits from Menards or Home Depot or wherever. Try to get the ones with zero rake angle on the tip. Some of the more expensive ones have a negative rake angle which is preferable when drilling masonry but does'nt work when drilling metals. They have to be reground to zero which requires a green wheel. AlOx wheels don't do much to carbide. The typical cheap drills come in sizes from 1/8" to 1/2" or greater. There is usually a size that will be close enough.

Use a drill motor with a lot of torque and a speed typically less than 500 RPM. You can use a lot of pressure, especially in hard or tough materials.

I have used these drills sucessfully on grade 5 and 8 bolts, stainless steel and even titanium.

In a pinch, used carefully, they can even be used to nibble out broken high speed drill bits and taps.

Also, don't be afraid to exercise your vocabulary. There's always the chance that you'll scare the bolt loose. Just be careful to avoid causing colateral damage to nearby women and children.

 

[cranetruck]

USPS got me the lefthanded bits from Will in record time, only two days from CA. Thanks again Will!
The bits worked too well and cut the grade 5 bolt without turning it. I put a so called, screw extractor of the tapered spiral kind in and even used the impact on it without budging the remains of the broken bolt.
It's now becoming a cost factor, getting a lefthanded tap and bolt may still not do it, so I'm asking, does anybody see any problem with me drilling the boss through and through and installing a longer bolt with a self locking nut?
It may have been suggested in the above posts, but here is an image showing it. The hole is already 2/3 through and has 5/8" course threads.

 

[alphadeltaromeo]

If it doesn't come out...like it's not...why not leave it in there and tap it and put a smaller bolt to hold on your "implement"?

I know, cheesy huh

 

[poppop]

If you are going to drill it anyway, try wire welding or welding with a very small rod to close up the hole. Weld just a little and throw cold water on it. Continure this until you can weld a nut onto it. When you weld the nut quench it again. I would bet it would come right out. The easyout expanded it but the quenching will cause it to get smaller and loosen it up. I tryied to remove a bearing race from a combine for a day one time. I gave up and carried to to a machine shop. He spent one miniute welding a bead inside the race, threw cold water on it, pulled it out with his fingers and handed it to me. When I paid the bill he said I charged you for knowing what to do, not for the time it took me to do it.

 

[alphadeltaromeo]

Lloyd

I've seen that as well...that's what I was told to do when I had to fix the final drive on the CAT track loader...was a bear but that simple step made it a breeze.

 

[Scrounger]

Bjorn,
Do you know what size and thread count the old bolt is? If it was me, and I knew the size of the bolt I would just drill the old one out as close as possible without hitting the boss threads. Then I would take a cape chisel to knock out enough of the old bolt so as to as to get a tap started. If you can get a tap started it will cut the old bolt out and leave the threads for a new bolt. Just remember to use a lot of oil when using the tap.

 

[WillWagner]

Bjorn,
Looks like you have it very close to center. I'd maybe go 1 more size up, if it's not gona be into the threads. Then you can use a small cape chisel. Or, if you have a die grinder with a tapered bit, you can oval the hole just to the threads then use a cape or punch ground to a point and peel it out. Did you go all the way through, looks like a through hole? If not, do it. Or, since it is on center, drill it to the proper size to tap the hole, i.e, 1/2 in capscrew, 29/64 for a 1/2 x 13 thread pitch, then use a good tap and push the stuck threads out the back or pull them out the front. Can't believe USPS got them there...the bits, that fast! Oh yeah, soak it with a good penetrant, i'm sure you have though!.

 

[WillWagner]

Sorry scrounger, didn't read your thread . What he said

 

[Jones]

Bjorn, what size is the current through hole you've drilled? From the pictures it looks like you've still got a ways to go before you get close to the threads; and, the bore hole needs to be the entire length of the broken piece as it's purpose is chiefly to relieve the inner strength so as to allow the bolt shell to collapse and release it's grip in the threads.
as a point of reference; when tapping a 5/8" NC thread you need a 17/32" tap drill to give 75% thread depth-- so a 1/2" drill would still be 1/32" under. It looks like you're somewhere around 3/8" right now and so I'd go out to 7/16" in one jump-- now that your bore hole is established, going in big increments encourages the drill to try to 'grab' the shell and spin it out as it turns. It looks like there's plenty of clearance on the backside of the boss so if you don't have a LH bit that big, then a RH will do the same job-- it'll just screw the broken piece on through and out the back. The left hand spiral drills are good as they turn the direction the bolt would normally unscrew but they're also the only thing to use if you're working on a blind hole.
Be very careful about trying to chase the threads if there are still pieces of the old bolt thread in the hole. The chips will gall and sieze quite often and a snapped off tap means EDM time and that's a real money-maker for a machinist.
Once all the old thread pieces are out, go in with a "bottoming tap", NOT a starting tap as the existing threads are already there and just need to be cleaned out and you want the strength that a bottoming tap will give. Flood the hole with carb cleaner or brake-kleen as you chase the hole and I'd probably take it real slow-- 1/4 to 1/2 turn at most then back the tap out to break off any chips, all the while slucing the hole out with the carb cleaner to wash the threads clean.
This is the Voice of Experience speaking; If you get to the point where a helicoil is necessary-- use the tap drill and tap supplied in the helicoil kit. DO NOT use a regular tap as they're oversized for the job and the helicoil will never stay put.

 

[cranetruck]

The current hole is 3/8" and it does go through the bolt. It is a blind hole and about 1/4-1/2" of space beyond the broken bolt (wonder how in the world it snapped off anyhow, defective!?).
As mentioned above, the tapered screw extractor is no good, unless there is a lot of material left to keep it from jamming.

The hole is off center about 1/16" and it is all soaked with penetrant(s).

Thanks for all your advise! I'll keep you posted with updates and I'll hold off on the through and through drilling (it's a hobby, and no deadlines. ).

 

[Jones]

If the back of the boss is in air then drilling all the way through for the purpose of getting at both ends of the broken bolt isn't a big problem. If it backs up to metal then leave it a blind hole. They must have done it that way for a reason. Bolts die from a variety of reasons; overtightening, allowed to loosen and get subjected to vibrational stresses, internal defects such as stress risers or hidden cracks, old age... the list goes on.
At what point do we need to ship you a crate of rabbit's feet?

 

[cranetruck]

...
At what point do we need to ship you a crate of rabbit's feet?

Who needs rabbit's feet? Found these under the battery box located under the companion seat the other day. May have been there since the day the truck was issued or perhaps a year later. Thirteen cents.....

 

[poppop]

Well I spent two hours today welding nuts to a broken wheel lug stud and then twisting them off. Heated everything cherry red and still no luck. GRRRRRRR!!!! Tomorrows another day.

 

[cranetruck]

Got out the remains of the bolt this afternoon. A 1/2" bit snagged it and drove it in and loose. Had to use a chisel to turn it back out. I'm pretty sure a 1/2 inch lefthanded bit would have done wonders.

Now, the threads are damaged, so I'll be using bushings and a bolt, which goes all the way thru and a locking nut on the far side.

I think that the reason for the blind hole is to make assembly easier.

 

[alphadeltaromeo]

At least you're moving forward...that's a good thing!