I have never drilled out a bolt before. I have a stripped cold-start hex bolt and a stripped six-point timing cover bolt. I bought the extractor with the reverse spirals, but I didn't want to start trying to drill it out with out practice. I purposely lodged a screw into my vase boss and stripped it and I went to drill it out and the drill bit only gouged out the center x on the philips head screw and no matter how much I drill or add force, the drill but will not go in at all. The screw is about 1.5 inches in length, but the drill only ate up the upper center portion. I even tried drilling it with the extractor bit, but nothing. Please advise.

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1990 190E 3.0L

Is your drill motor going in reverse ?

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

No, I tried switching it in the other direction (which was reverse) and still nothing. Is there a special type of still bit? How much force do I apply?

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1990 190E 3.0L

Should take very little force. The bit should be biting into the bolt.
You say ' reverse spirals'. Did you get the type that works with a wrench
or a special drill motor bit ?

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

reverse spirals = left hand extractor. So I turn the direction to loosen the stripped bolt, but the bit is actually tightening as the threads are going the opposite direction. Can I drill with the extractor itself or should I use a drill bit? maybe I need to get the left handed drill bit?

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1990 190E 3.0L

Drill with a smaller bit first to make a hole,then use your larger bit.Then hammer easy your extractor in the hole lossen bolt out.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

Here's some more advice

Screw extractor | easyout | broken bolt removal - YouTube

Or here =>

More than you are likely to ever want to know about OM61X piston vacuum pumps

(Efforts trying to get corroded bolts out of a vacuum pump)

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

FIXED!
For the timing cover, I used the Irwin socket that grabs the stripped bolt. There was just enough room for the socket to fit over the bolt and in between the recessed hole at the center of the timing cover. I hammered the socket down onto the bike and was able to turn it out. Unfortunately, I did not have a spare bolt so I had to reuse the stripped one, but I took the sides down and made it into a 9mm socket bolt so I was able to torque it back in with no problem. The other bolt was more of a challenge as it was my col d start valve bolt and there was no room at all to get the grabber tool over the bolt. I started drilling it, but I did not see the the drill was even going into the bolt. I then switched to a diamond studded rotary saw, but I could only cut half of the tio of the bolt. Finally, I took out the other bolt closes to the firewall side, grabbed the csv with vice grips and began twisting and turning it and moving it around until finally the other bolt became loose and I was able to twist it out. I of course broke a small piece of the brittle plastic hose that the csv sits in, but nothing that would cause it to have an ill-effect. I do want to replace the plastic hose, but I can wait on that for now.

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1990 190E 3.0L