Dull drill bits.... drilling tips?

[RonA]

My concern would be how to grind them once blunt??

I have a so called "green stone" on my grindstone, which I use to sharpen TCT lathe tools. It also works brilliantly on masonry drills so don't think the cobalt drills would pose much of a challenge, although frequent cooling of the drill bit would I suspect be necessary.
RonA

 

[ukracer]

I have a so called "green stone" on my grindstone, which I use to sharpen TCT lathe tools. It also works brilliantly on masonry drills so don't think the cobalt drills would pose much of a challenge, although frequent cooling of the drill bit would I suspect be necessary.
RonA

I was speaking more about the fact sharpening drills is not a skill I have picked up easilly , even on normal tipped drills. I would not know how to start doing a split point grind with 135 degree cutting face.

 

[PhillipM]

You can do it freehand with a little practice, it's a complete swine on smaller bits mind.

 

[Wayne.]

I bought a set of drills from these guys and the cutting compound and they KICK ASS, just have a look at the videos on their website

http://www.ttp-hard-drills.com/

For that kind of money i would bloody well hope so lol

 

[fizzy]

For that kind of money i would bloody well hope so lol

I couldn't believe the prices! Unless you are drilling something special are they really worth that money?
4x the price but do they last 4x as long?

 

[PhillipM]

You could get some proper drills for that money.

 

[stee1e]

is it worth getting a protractor to sharpen these bits properly?

edit: stupid question. For the cost of £3 I'm gonna get one. Ta

 

[brightspark]

a bit of info on the drill bits

 

[stee1e]

a bit of info on the drill bits

Thanks, just printed that. Is that from a PDF engineering book? I should find me one of those.

 

[brightspark]

Thanks, just printed that. Is that from a PDF engineering book? I should find me one of those.

its one sheet from harold halls engineering pages if u go to home made tools.com all his articles are on there well worth a look

 

[brightspark]

here http://www.homews.co.uk/page3.html

 

[stee1e]

here http://www.homews.co.uk/page3.html

Wow! Thanks

 

[langy]

Just like any other drill, they're still HSS, just modified with cobalt for more high temperature hardness, to be honest, for this job any decent split point drill with a bit of lube should go through in one go.

Nothing like making the job more complicated than it needs to be

 

[Rig Pig]

The perfect opportunity to build a Quorn T&C grinder! And learn the delights of four facet drills. I have been planning to build one for years .... One day!

 

[shedfull]

This bloke knows what's what

 

[ukracer]

This bloke knows what's what

It still all looked the same to me lol

 

[Kent]

Drill sharpening is dead easy once you have done the first hundred! Once worked with a guy who could do it on site with an upturned angle grinder, never managed to emulate that trick though. A worthwhile thing to learn as not only is it economical it allows you to modify the angles etc to suit the job. To practice start with bigger drills as they are easier to check by eye, remember it must centre and both rakes should cut evenly. Honestly without good light and my reading glasses to hand I do it by feel and check it by spinning the tip against my fingertip for even rakes but someone gave me a big old box of old second hand drills to sharpen up when I was about 17 years old and made me get them all right

Too many pilots not good in fact a big waste of time, 8mm pretty much one hit in 3mm with a hand drill especially if you modify the grind in the centre and are not needing spot on the dot. The pilot if used should only allow correct centring of the bigger drill. Running at the right speed is critical