Author Topic: Left handed drill bits  (Read 278 times)

cobbadog

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Left handed drill bits
« on: 10 April, 2019, 04:36:55 pm »
Anyone know about these left handed drill bits. I saw a glass jar half full of them last weekend and was wondering what they were designed for.
All the flutes run the opposite direction of a normal drill bit an oddly enough all of these were broken at or near the cutting edge.
Cheers, John & Dee. Coopernook. NSW.

cranky crank

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Re: Left handed drill bits
« Reply #1 on: 10 April, 2019, 04:50:07 pm »
good for drilling out broken bolts and studs. I have used mine a few times and most of the time the drill bites in a bit and then the stud winds out as you are using it.

wee-allis

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Re: Left handed drill bits
« Reply #2 on: 10 April, 2019, 07:05:12 pm »

Cobba, Right twist drill bits are for drilling holes and left twist bits are for filling them in!!
If it's old, treat it like gold.
C1300 Inter, 38 Allis B,47 VAK1A David Brown,48 TEA Fergie, 53 Morris Six,  Moruya, Sth coast NSW.

cobbadog

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Re: Left handed drill bits
« Reply #3 on: 11 April, 2019, 04:16:49 pm »
Your right Steve.
Apparently many use them for drilling out broken stud etc as already suggested.

Thanks for the replies.
Cheers, John & Dee. Coopernook. NSW.

wee-allis

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Re: Left handed drill bits
« Reply #4 on: 11 April, 2019, 07:00:50 pm »

Glad you got that sorted John, but now tell me how you worked out that the jar was half full of drill bits and not half empty?
If it's old, treat it like gold.
C1300 Inter, 38 Allis B,47 VAK1A David Brown,48 TEA Fergie, 53 Morris Six,  Moruya, Sth coast NSW.

cobbadog

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Re: Left handed drill bits
« Reply #5 on: 12 April, 2019, 03:46:48 pm »
Because it was full at the bottom and not at the top. you can't fill the top first, silly!
Cheers, John & Dee. Coopernook. NSW.

wee-allis

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Re: Left handed drill bits
« Reply #6 on: 12 April, 2019, 07:11:35 pm »

Touche!
If it's old, treat it like gold.
C1300 Inter, 38 Allis B,47 VAK1A David Brown,48 TEA Fergie, 53 Morris Six,  Moruya, Sth coast NSW.

davo

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Re: Left handed drill bits
« Reply #7 on: 17 April, 2019, 12:21:44 am »
And probably at a guess, the reason they were broken at the cutting edge would be they were used on the hammer setting in a hammer drill to get out broken bolts/studs as the hammer effect helps loosen them (speaking from experience). I'm also guessing old mate didn't know how to sharpen left hand bits, that's why he has half a  tin of busted ones

cobbadog

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Re: Left handed drill bits
« Reply #8 on: 17 April, 2019, 02:37:55 pm »
The owner of these bits bought a box of drill bits at a garage sale and was sorting through the sizes and those that needed attention. After the sorting took place he worked out that all the broken ones bar one were opposite twist and he now has them in the jar and he is proud as punch to show them off.
Cheers, John & Dee. Coopernook. NSW.