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Your Left Hand Drill Bit Procedure

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gdocktor3

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I recently purchased my first set of left hand drill bits to hopefully save a few steps when removing broken fasteners. They are mechanics length cobalt by Snap On. So my question is - when you are using them, after using heat, lube and the center punch, do you start with the smallest as a pilot bit, or go with a larger size? I thought I would start with the smallest bit and then step up maybe 2 sizes. This way it may "catch" the broken fastener much like when you are using regular bits and the drill sometimes locks up. I thought maybe that jolt would help break it free?? What are your methods?

Also, does a drill with a keyless chuck tend to come loose a lot when using left hand bits?
 
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toolman9w

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That is the way I use them with. If it is real hard stuff I may even just step up a size at a time. When you heat them don't turn them red, it will harden them and make drilling harder.
It depends on the quality of the keyless chuck.
 
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Leaflessshadetree

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Don't ask.
Depends on the size of the bolt, and why it's broke.
Center punch and drill straight. I usually start with a small bit (not the smallest if it is a large bolt). I'll half heartedly try a small easy out. Then I go to a bit 1 or two sizes smaller than the smallest thread dimension, depends on how centered and straight my hole is.
 
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SIKPUP

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I try to do the first hole with an 1/8" regular bit ! The first hole is normally the hardest on bits ... Why screw up the Leftys ?
 
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cheechi

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SIKPUP said:
I try to do the first hole with an 1/8" regular bit ! The first hole is normally the hardest on bits ... Why screw up the Leftys ?
Click to expand...

I learned this lesson the hard way. Also if you can, I have found an air drill is a better choice than an electric, corded or cordless.
 
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MikeF2316

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I agree with the guys who suggest using a normal bit for the pilot. Generally I skip up several sizes at once. And I've found success of any drilling of broken fasteners is directly related to how close to center your initial hole is.
 
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alfazer

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To your second question...I use left hand drill bits in a keyless chuck and find no difference in grip to drilling in forward. The chuck still tightens in the same direction.
It's a Panasonic cordless.
 
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Wamsutta

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The best case scenario is the bolt breaks clean, leaving a nice flat surface for your center punch mark. Then if you get the center punch mark perfectly centered, you're home free.
 
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redmondjp

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Wamsutta said:
The best case scenario is the bolt breaks clean, leaving a nice flat surface for your center punch mark. Then if you get the center punch mark perfectly centered, you're home free.
Click to expand...

Well, if my experience is anything, not quite! Maybe my drill bits aren't perfectly sharpened or my approach angle isn't correct, but I seem to have the knack of drilling quite far off-center no matter how perfectly centered I get the punch mark.

I recently (and successfully) used (for the first time) the trick of welding a nut onto a broken-off stud - I used my oxy-acetylene outfit, so in the welding process, the stud got nice and hot and then I sprayed it with penetrant shortly thereafter.
 
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gdocktor3

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Ok thanks for the tips. Now let's sat you work your way up to your 1/4" bit, but it's still not coming. Do you continue stepping up with the lefty bits if there's enough meat left or do you switch to extractors? Also, will cobalt bits drill through broken extractors? I know my regular bits won't lol
 
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Wamsutta

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I prefer to go straight to the extractor first before attempting to drill the entire bolt out. If you use the square extractors, the chances of breaking one are greatly reduced. The first time I tried a square extractor, I had great success. It was a broken grease fitting on a ball joint, but I had the control arm off the car and and sitting on my lap. I just took my time and went slow with my reading glasses on.

I used the exact size extractor for the diameter of the bolt that Proto wanted me to use, plus I went down in size on the drill bit by 1/32 of an inch; that way the extractor didn't bottom out on the blind hole. The drill size stamped on the extractor is sized for through holes.

The grease fitting laughed at my brand new DeWalt HS drill bit. I ended up getting a solid carbide drill bit from one of those special hardware stores that's been around since 1958. This time, the carbide bit was laughing at the grease fitting. ;)
 
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gdocktor3

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I suggest going back to that hardware store from 1958 and buying up their entire line of drill bits because in 2017 they'll probably be gone, if they're not already.
 
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akalian

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The guys at DoAll schooled me in how to use left hand drill bits a very long time ago. And I've been using left hand drill bits to remove broken off bolts ever since.

Everytime I tell somebody to use a left hand drill to remove a stuck bolt, all I get is HA, HA, HA like it's some kind of joke. What a pleasure it is to see the pros here on Garage Journal offer excellent advice on how it's done.

Once you get the hang of it, and the first time you spin the broken stud out of the hole, you will be a left handed drill aficionado from then on.

Just a breath of fresh air.
 
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chrisnazzy

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Recently a freind/coworker asked me if I could help him remove a broken bolt out of a Mercruiser gimbal housing he was working on. I thought it would have been a perfect candidate for my left hand drill bit / extractor set. I invited him over after work but unfortunately when he showed up he had already broken another extractor off in the hole he started to drill. That was pretty much the end of that. No drill bit I had would even bite into that extractor, nor would the bit he went down to the hardware store and purchased. Moral of the story: Patience is a virtue and use the right tool the first time.
 
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akalian

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chrisnazzy said:
Recently a freind/coworker asked me if I could help him remove a broken bolt out of a Mercruiser gimbal housing he was working on. I thought it would have been a perfect candidate for my left hand drill bit / extractor set. I invited him over after work but unfortunately when he showed up he had already broken another extractor off in the hole he started to drill. That was pretty much the end of that. No drill bit I had would even bite into that extractor, nor would the bit he went down to the hardware store and purchased. Moral of the story: Patience is a virtue and use the right tool the first time.
Click to expand...

No matter how careful you are, at some point this will happen to you. I've found that R-134A is cold enough to freeze the easy out or extractor so it shatters when you whack it with a chisel. It's agony and time consuming, but the intense cold of the R-134A will get the job done. It's a cheap fix, about $8 a can at Wal Mart.

But here in the Peoples Republic of California some nitwit bureaucrat decided that there needs to be a $10 deposit on each can of R134A purchased that will be refunded if you bring the empty can back. And get this. You have to bring the empty can back within 90 days to get your $10 back on an $8 can of R-134A. I mean WTF is that all about?
 
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chrisnazzy

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akalian said:
No matter how careful you are, at some point this will happen to you. I've found that R-134A is cold enough to freeze the easy out or extractor so it shatters when you whack it with a chisel. It's agony and time consuming, but the intense cold of the R-134A will get the job done. It's a cheap fix, about $8 a can at Wal Mart.

But here in the Peoples Republic of California some nitwit bureaucrat decided that there needs to be a $10 deposit on each can of R134A purchased that will be refunded if you bring the empty can back. And get this. You have to bring the empty can back within 90 days to get your $10 back on an $8 can of R-134A. I mean WTF is that all about?
Click to expand...

You answered you own question with the "Peoples Republic of California" statement. I grew up in CA but have lived in AZ for 22 years. I can however stand on my patio and look out and see CA. Anyway that would have been cool (no pun intended) to try you R-134 trick on this situation. We don't have to pay that $10 fee here. Of course unlike CA, AZ hasn't come to the determination that everyting under the sun causes cancer either.:):)
 
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justme-

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No cobalt won't drill a broken extractor, only carbide will. There are tap remover carbide bits out there, but generally expensive.

Taps van be shattered fairly easy, easyout not so much. I like the square over the reverse taper Do to higher perceived resistance to breaking.
I guess I'm the odd duck, I don't start with the smaller lefty, but the one closest to the size I need, which is almost always one of the two.smallest in my set ( the snapon set but from the manufacturer not off the truck).
I've never heard a benifit to stepping up with them over the initial drilling, and unless you buy a machinists set (like Norseman's) the truck sets are woefully lacking in sizes, so I'm not using it to make a hole so much as hoping it will free the fastener. It's my next hole which is with a normal bit so I can size it for the extractor.
 
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Superbec

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I'm so dumb I broke all my small sized lefties.. if the bolt is not sized in there they will take it out before you get the chance of playing with the extractors :(
 
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