Left handed drill bits

[JIMMIE]

I have a few left handed drill bits. I use thes exclusively for extracting broken bolts. I was wondering if this is the only purpose for which they were intended.

Jimmie

[Van Chocstraw]

You could make a left handed door with them.

[DT]

Multiple spindle drilling machines have every other spindle turning counter cockwise. I think those bits have a driving flat, though.

[Stormin Mormon]

If I'm installing a deadbolt on a door with left handed reverse bevel, do I use right handed bits?

[RLM]

Yes. I used to sharpen some broken bits backward and paint them yellow just for this purpose. The colour was only a way to recognize them in the drawer quickly. They worked great when needed. Why would they have to have multi uses anyway? This one use was a real enough time saver when needed.

[Stormin Mormon]

How does one get a left handed flute out of a right handed bit? Even if it's broken off, it's still a right hand twist.

[mm]

They're good for use by left-handed people with left-handed drills.

But I guess I only use tthem for extracting specialty screws and broken bolts.

The first time I tried to buy these things, at least one hardware guy thought I was kidding. He didn't have left-handed nails, either.

[Joe]

Commonly used when hand drilling out damaged right hand threads in soft metals so that the drill doesn't seize and kick back taking your knuckles with it. The drill is usually sharpened with very little rake as well. No that's not a grass rake, you humorists.

Jioe

[IGot2P]

Yeah, but I would bet that he had some metric Crescent wrenches. :-)

[jeff_wisnia]

I wuz gonna ask that too.

But, I imagine you can grind the cutting edges so they'll work, but the flutes sure won't wanna move the chips up out of the hole, will they?

Jeff

[Jules]

I suppose to remove a bolt you don't want it generating piles of metal and drilling into the bolt, anyway - all it needs to do is bite and draw the bolt out.

Maybe I'll give it a try - I think I've got a few broken bits somewhere.

Always wondered if there's a good reason why normal bits drill in the same direction as screw threads, or whether it's it just cooincidence...

cheers

Jules

[Stormin Mormon]

I'd guess that a left ground right bit would scrape, rather than drill. I can't imagine it being at all useful.

[Stormin Mormon]

Might work to bind and rotate a bolt. Never know. Please come back and tell us what you found.

[Jerry - OHIO]

I was sharpening some drill bits I got in a junk store and couldn't figure out why I couldn't get right. Yep it's a 3/8 " left hand, so I stand backwards when I use it. There are " Left hand crescent wrenches ! I do own one. it's funny when I lend it to some one that is working under a car , the dam thing drives you nuts. I used to throw it across the yard until I got used to turning the barrow back wards

Jerry

[Jules]

Will try and remember to give it a go tomorrow...

It's possible it'll just bind solid but the bolt won't move - and the drill will...

[Stormin Mormon]

At which point you'll be whistling, I mean, fluting, Dixie?

[RLM]

Only the tip cuts and catches to reverse the broken bolt. I learned to sharpen bits by hand many years ago from an old machinist. This is something he showed me before I had ever seen a left twist bit.

[RLM]

The bit is only intended to catch hold of the broken bolt with a reversible drill motor and twist the broken bolt out of the hole. The flute at the end is ground to cut at a low angle to catch the bolt and remove it. You can drill a small pilot hole in the center of a stubborn bolt for the left hand sharpened tip to catch. Done it for years prior to retiring. Use the method still if needed.

Don't need it as often, that's all.

[RLM]

If need be I have three different styles of easy outs. The long twist with a tap wrench end, square easy outs with cut edges to catch and short ones with many edges that have hex heads to turn them out. The reverse drill bit is a first try and quickest. Snap-On and Mac carry them all if you care to look the styles of easy outs up.

[Joe]

Left hand drills have left twist to remove chips. There are router bits and CNC bits, however, that are 'downcutting' so that chips are kept away from the surface for specialized reasons.

Joe