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Left handed drill bits

cobbadog

Registered
Hi guys,
We went away to a small rally last weekend and caught up with a number of other collectors of old tractors and stationary engines. One of them had a jar partly filled with drill bits that curiously all had the cutting edges snapped off. He asked me if I knew anything about them as he grinned I knew something was not normal. It took me a while but then I noticed that the flutes all were running the opposite direction of a normal drill bit and they were all broken.
what would be the reason for these drill bits to cut in the opposite direction? I am stumped on it other than drilling out broken studs and hoping it helps free them up.
Look forward to the replies on this one!
Sorry I have no photos of them.
 

Paul Spence

Subscriber
Last Subscription Date
01/02/2020
I use then to remove broken off flush, bolts, grease fittings, etc. (Lefty Loosie :p ). I guess down under, some things :uhoh: , naturally rotate differently :O , but I've never been their ;) .
 

ronm

Subscriber
Last Subscription Date
07/10/2019
There is no better feeling than when a left hand bit grabs and spins a broken-off bolt out. . . try it sometime. . . beats the hell out of a right hand one spinning it to the bottom of the hole.
 

J.B. Castagnos

Registered
Last Subscription Date
01/01/2006
When there's a chance the bolt might unscrew I drill a small pilot hole, use a larger LH drill bit, it will bite in the small hole and unscrew.
 

I like oldstuff

Registered
Last Subscription Date
11/09/2015
Left hand bits are often used in manufacturing in multiple spindle drilling heads. Let's say drilling all the holes for a head in an engine block in one operation. These drilling heads have the spindles geared together. In some cases there isn't the room to gear it to getting all spindles turning clockwise. So the spindles that run CCW get left hand bits.
 

Tony Rye

Registered
Last Subscription Date
08/24/2018
as a field mechanic. I only used left-handed bits. Eazyer than keeping both kinds
 

slip knot

Subscriber
Last Subscription Date
12/27/2019
I bought a set of lefty bits on the hope that I never need them. I also put a VFD with reverse on my drill press.
 

Peter Holmander

Subscriber
Age
71
Last Subscription Date
12/23/2019
They used to use them allot on Brown & Sharpe screw machines. We used to have allot of fun with them when I worked in the shipyard. Give one to a guy and watch him push like crazy on the drill.
 
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