Left hand drill bits

[PaGlenn]

I was looking through a Harbor Freight Tools catalog and noticed the left hand drill bit set.
Are they used for work that a right hand bit can't perform?

 

[Bob]

One use is removing a broken off stud or bolt that is NOT stuck in position. When you drill it out with the LH bit, hopefully, the bit "catches", and the broken part screws out.

 

[jjamna]

What is the part #? I would like to get a set myself. Great for getting broken bolts out.

 

[Jim in Ma.]

I got a set from Northern - they come in very handy

 

[Phil9N3667]

Left hand bits are wonderful if the bolt/stud isn"t tight and will back on out! In my line of work as a mechanic at a Mack truck service dealership years ago, I ran up with a spot where a L.H. bit wouldn"t work! The old Mack transmissions had a clutch brake mounted on the bottom countershaft and it was locked in place with a 1/2" fine L.H. bolt. Talk about confusing to get out if you weren"t thinking sraight that day! Ya don"t use L.H. bits much but when needed they"re worth their weight in gold. If push came to shove I have taken a regular bit, put it on the bench grinder and converted it to L.H. You don"t drill very deep but it will work. Have a good weekend folks.

 

[Anonymous-0]

For most of us, the left hand drill bit is most useful as a bolt extractor, as was stated. However, left hand drill bits originally were designed for use in high production applications, where many spindles were geared together in a gear train to produce a specific part quickly. It was often easier to produce a drill bit for a spindle turning "the wrong way" than to include an idler gear in the machine to get the spindle turning "the right way".

 

[PaGlenn]

Thanx all for the comments. Adding a set to my list. They are offering a 13 piece set for $6.86
and a 4 piece set for $2.99. From DrillMaster. Lot No. 95146 and 38180. My paper says the sale is until Oct.29.

 

[CWL]

Yep. They're commonly called screw machines. Last place I worked had a whole production line of them. They make a manufacture a lot of money when they are set up right!

 

[Anonymous-0]

Not going to get quality for that price. Hanson made some extractor sets with LH bit right size to use with EZ outs in set. I broke a few LH bits in set and replaced them with better quality Lawson or LH bits from MSC, mscdirect.com or mcmaster.com Just like any drill bit get what you pay for.

 

[moseed]

They work well as extractors if you start small and increase bit size as you go. If you can get three graduations or more (hard to do with small studs/bolts) you increase your odds of success tremendously. Also go very slowly. Your bad luck will get worse if you snap one off. Use name brand bits. Harbor Freight serves a purpose but this is not one of those situations.