Stripped Screws

[Kanani]

The bolt is abviously gaulded.

Normally the threads of a bolt only take up about 90% of the space in a threaded hole. If one does not fill that void with an appropriate thread compound, the hole will have voids that will fill with water and corrosion will occur until that void is totally full. This is particularly common in unmatched metals like screwing S/S into aluminum.

Once there are no voids in the threads, it becomes very difficult to impossible to unscrew the bolt (as you have found out). The key is to loosen up the corrosion in the voids so that the bolt can move.

Before trying to extract any bolt on a boat, it's a good idea to give it a few good taps to loosen debris in the threads. When you are in the state that you're in now, you can still tap around the area, spray it with PB Blaster (don't waste your time with WD40) and continue tapping with the goal of loosening the offending material.

After you've done this for a few hours, take a small chissel and try to chisel a small slot in the top of the bolt/easy-out combination. Hold the chissel at about a 45* angle in the direction that you want the bolt to turn. Just do this enough to make a slot for the chissel to do it's job. Then do the same on the opposite side of the surface. Be patient and don't hit it real hard. Just steady taps, first on one side, then the other (for balance) is all that it should take.

If you are patient, you should be able to turn the screw enough to get a pair of vise grips on it and turn the screw out.

[Zach]

Have you got it loose yet?

If not time to break out the heavy machinery. File a flat spot on the top of bolt, or broken stud and center punch it. In your case, simply centerpunch the center of the machine screw. Now start drilling. Do you have other bolts out to figure out how long it is?

Center punch, use a centering drill bit and drill down through the bolt. Hold the drill straight, don't flex the bit. Use oil to lubricate and cool the bit, don't make big fancy spirals start and stop pressure once the chips start to flow so the heat leaves with them.

Once you have a straight hole, enlarge it. Drill out as big as you feel comfortable without getting into the threads in the part. Doing this relieves the bolt. Bolts are under tension, as they thread in the threads try to stretch the bolt out. Relieve most of the metal from its inside, it gets loose. Sometimes it is helpful to grind the head off to relieve further tension... last resort!

Now, don't go reaching for an easy out. Tap a left hand thread (or right hand if the fastener is left hand) into the hole, go get another fastener, preferably one that goes just shy of bottoming out. "Tighten" the left handed thread and it should back out the leftover threads in the old bolt.

Use as high a grade of bolt that you feel comfortable drilling... More than 5, less than 8... So if it breaks off, you don't have to drill something super hard. When you snap an easy out, it means ten times the work.

Good luck.

[GordMay]

Great ideas!!!
Because there’s no single “all-purpose” solution to problem fasteners, all of these excellent suggestions combine to making a complete arsenal of techniques.
See also:
Tools and Techniques for Removing Frozen Fasteners ~ By Jim Gilbert
http://www.practical-sailor.com/news...nfasteners.pdf

[toewsrus]

One Down One To Go.

I tackled the tough one. It was the one with the easy out broken off inside. I tried a reverse drill bit, a cobalt bit, but nothing would touch it. I found some easy out extractors at MSD but for some reason I went with a carbide drill bit from Fastenel. It was rather expensive, but it cut through the hardened steel like butter - very nice.

It drifted a little and hit the traveler end. Thankfully I was able to just turn it around, redrill and retap and the peice was usable again.

After all the great ideas, I plan on never getting into this predicament again and if I do:

I'll just sit back, have a cold one, get my zen in line while using some wd-blaster, a hot impact tool, some ice and two battery cables. That should do it.

[johneri1]

Nice job! The other one should be even easier. . . . In my previous life I was a journeyman job shop machinist, so here's my two-cent worth: left-handed drill is the go-to fix, the shorter the better (less chatter) grind it just long enough to break all the way through. (It'll drive you crazy putting a cutting edge on a drill with a left-handed helix.) If the screw does not unscrew during drilling, make your own easy-out with four straight flutes (no helix). You need just the right amount of angle to gain proper purchase in the hole--broken taps should always be saved, these make the best easy-outs. Be careful while grinding it to keep it from turning color (losing heat treat). Use a tap handle to screw out the broken screw. Careful shaping of the easy-out is critical.

[perchance]

I have done this job many times. First of all make sure your wrench is not rounded off since this is usually the cause of rounding out the socket head. if the the head is rounded out you can peen it back into shape or pound in a wrench that is close to the right size ( sometimes metric or imperial what ever works). If your careful or lucky or both drill the head off the bolt then
drill the body of the bolt out with the right tap drill size and use a tap to remove the old thread. It's finicky work but it can be done