Stripped belt tensioner bolt

135 Views 9 Replies 3 Participants Last post by paulrondelli, 4 d ago

JimmyJosh

Discussion Starter · 4 d ago

I accidentally stripped the belt tensioner bolt. The only way to get out its remnant is drilling and then use easy out. I have tried like ten drill bits without success. I don't know what kind of metal this bolt is made of. Which drill bit would you recommend?

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amc49

· #2 · 4 d ago

I'd make sure the back of the hole does not go all the way through first with possibly some bolt length out the back you could back it out with........

Size of bit VERY important there, too big a hole and you expand the outer portion toi NEVER come out, too small and you then break the EZout to make it 10X worse. Start with smaller bit and get bigger, the smaller bit bites in quicker to start the hole. No high speed steel or Harbor Freight gold colored bits, they are too soft and why you are going nowhere. Left hand bit is better, it may even break the piece loose to come out.

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amc49

· #3 · 4 d ago

Wallowing around to ruin the job like a blind fool there, centerpunch the bolt to hold bit on center or give up in wreckage.

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JimmyJosh

Discussion Starter · #4 · 4 d ago

amc49 said:
Left hand bit

I have tried NEIKO Screw-Extractor and Left-hand drill bits without success. Will appreciate if there's a specific drill bit you can refer me to.

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amc49

· #5 · 4 d ago

Skills there are 10X the value of a specific bit. To begin with, you mike the thread OD and then pick a bit somewhere around 2/3 that size, THEN you need an outlet for numbered bits as often the available ones are in 1/16"s and useless to you.

Beginning to see why there is no specific bit yet? I've repaired hundreds of holes like that and there is NO specific bit. I start small on hole and work my way up.

And IF there WAS a specific bit then the extractor tool would be just as specific if not even more. The EZout used will kill you there and why there are so many fails.

The only specific thing I can come up with is that EVERY single hole I ever repaired ended up with something changing there to fit the situation at hand, where the skills come in, to know when to change.

The work is not going well, the wallowing around of bits has made the broken part even more self-locked in place than it was to begin with. The wanting of a 'specific bit' as well shows defeat about to happen, you need to walk off and give it more thought.

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amc49

· #6 · 4 d ago

I saved your pic and zoomed it way up. You started out with way too big a bit, the resulting hole has swedged the remaining thin wall material of the broken part out in expansion to really lock in tightly. You have a more serious problem now than at the start.

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amc49

· #7 · 4 d ago

Your next step is to pick a SMALL very hard NEW bit at half the hole size or smaller and drill all the way through the broken bolt. Then go up in size. It's easier to drill through hard parts with sdmaller bits. Then you go up to make hole bigger. Another reason why there is NO specific one bit.

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JimmyJosh

Discussion Starter · #8 · 4 d ago

Thank you so much for sharing your knowledge with me.
I should have expressed myself better! Is there a brand you can recommend? Amazon link to the product? Bear with me for asking you to spoon-feed me.

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amc49

· #9 · 4 d ago

Material matters far more than a brand and why you are failing. Get a carbide bit for drilling in harder metals only. Not going to Amazon search for you, you already got my more than 50 years of doing that work. Oil the bit, one reason you are tearing it up. Turn the bit slower to not burn it up. Again, the skills.

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paulrondelli

· #10 · 4 d ago (Edited)

This is one of the wrench turning skills that require patients and practice.

you cannot go into this "guns blazing" and trying to knock it out quickly.

You got great advice above. Make sure you get the first small bit EXACTLY in the center. Use a punch ... don't half ass this part.

The small bit will take some time. Go SLOWLY and do not put a lot of muscle behind the drill. Use oil and let the bit do the work. Let it cool down every couple of minutes.

If you break a carbine bit off in the hole ... then you are screwed.

There is a reason professionals get paid big bucks. There is also a reason that working on rusted out rides SUCK.

That spot looks relatively rust free? If you broke that one off without using a breaker bar .... then you need to stop hitting the weight room so much.

I have seen experienced guys go through a dozen or more bits..... with a really stubborn bolt.

just get the Carbine bit... they sell them at lowes and home depot ....... they are not cheap.

Start with a small bit and go larger until you can get and easy out on it .... or the bolt breaks into pieces. Once you have the hole clear you can always re-tap the threads

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