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Drill bits

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Grotto25/05/2019 10:02:00
124 forum posts
71 photos

I recently bought a bunch of drill bits and when sorting through them found a few are left hand.

I'll be able to use them in my mill, but wondered why they are made. I guess there’s a good reason, just can’t think of it. Anyone know why?

Michael Gilligan25/05/2019 10:05:11
14960 forum posts
638 photos

One good use is for drilling-out broken right hand threaded screws.


Simon Williams 325/05/2019 10:07:42
461 forum posts
75 photos

Hoard them carefully, and wait for the day you need to drill out a broken off bolt in something completely irreplaceable. They are absolutely brilliant at catching the remnant bolt, at which point it unscrews itself out of the blind hole like magic. Better than an easi-out any day.

Don't use them in a keyless chuck - many such won't hold in reverse. A keyed chuck (generally) will.

Rgds Simon

Edit - MichaelG types faster than I.

Edited By Simon Williams 3 on 25/05/2019 10:08:40

Circlip25/05/2019 10:30:38
1035 forum posts

They may have come from a flat pack furniture manufacturer. On multi drilling heads, some of the drill "chucks" rotate in reverse due to the centre spacing.

Regards Ian.

Mark P.25/05/2019 10:32:47
611 forum posts
6 photos

Loads on ebay.

Mark P.

Andrew Johnston25/05/2019 11:03:55
5183 forum posts
599 photos

Some production lathes normally run in reverse, like my Britan, so left hand drills are standard.


roy entwistle25/05/2019 11:11:20
1118 forum posts

Drilling left handed holes obviously


JohnF25/05/2019 11:48:26
929 forum posts
114 photos

Boley made a capstan lathe similar I guess to Andrews Britan, also ran in reverse with the toolbox/holder at the rear thus LH drills we needed


larry phelan 125/05/2019 17:36:27
602 forum posts
11 photos

Never thought about drilling left hand holes !!!

True,you learn something new every day.

Keep them coming.

V8Eng25/05/2019 17:44:26
1366 forum posts
28 photos

Don’t forget to use left hand threaded taps with them.wink

duncan webster25/05/2019 23:57:10
2420 forum posts
39 photos

Then you'll need a left handed spanner to wind the bolts in

Jeff Dayman26/05/2019 00:49:12
1758 forum posts
45 photos

As mentioned on an earlier thread, left handed drills are very handy for working on the port engines of twin screw ships, and also LHD cars as used in North America. By the way Duncan, most mechanics' toolboxes in the North America are fully stocked with left handed wrenches of various types, a few of which can be used on right handed fasteners also.....not sure about toolboxes in the UK......

Simon Williams 326/05/2019 07:35:59
461 forum posts
75 photos

If you want to drill two holes which are truly independent of each other, drill one left hand and the other right hand.

Because the left hand never knows what the right hand is doing

roy entwistle26/05/2019 09:24:13
1118 forum posts

Left handed spanners are easy to recognize, left handed screwdrivers are not as easy especially cross point ones


Mike Poole26/05/2019 10:31:34
2432 forum posts
53 photos

Can you fill a hole with left handed drill? Could be useful for a hole drilled in the wrong place.wink


roy entwistle26/05/2019 14:16:32
1118 forum posts

Mike Now you're just being silly

Roy laugh

Jeff Dayman28/05/2019 00:59:43
1758 forum posts
45 photos

Hold on Roy, Mike is on to something. I'm pretty sure if I put a 1/8" dia left hand drill in the electrode holder of my old Lincoln 225 arc welder I can fill a hole ..... as long as the ground lead and clamp are in place on the plate with the hole! smile

roy entwistle28/05/2019 09:22:42
1118 forum posts

Jeff OK I'll hold my hands up


Mike Poole28/05/2019 09:33:10
2432 forum posts
53 photos
Posted by roy entwistle on 26/05/2019 14:16:32:

Mike Now you're just being silly

Roy laugh

Guilty I’m afraid.


Hollowpoint28/05/2019 09:48:59
288 forum posts
30 photos

Maybe they are Australian? To counter that they are upside down and spinning the wrong way? 😄

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