Hard Coral

[BobFish]

I am trying to drill through hard corals and neither concrete bit or high speed steel will touch it.....anyone drill really hard coral

[kien]

I am trying to drill through hard corals and neither concrete bit or high speed steel will touch it.....anyone drill really hard coral

Diamond drill bit?

https://www.homedepot.ca/en/home/p.516-inch-diamond-drill-bit.1000529505.html

[Tyfighter]

A concrete bit will drill through it if you have it on have it on the hammer setting. If you don't want to risk cracking it you would want to use a diamond bit as stated above. What type of coral are you drilling and what size is the hole?

[BobFish]

used diamond bit, masonry bit wouldn't touch it, thanks for the replies

[WarDog]

You're drilling coral or rock?

[BobFish]

drilling very hard coral, some of it is softer!

[whatcaneyedo]

Like Tyfigher said, concrete/masonry bits will work but they need to be used in a hammer drill on the 'hammer drill setting'. The size/brand/quality/condition of the bit and drill makes a difference too. They are however pretty rough/violent and wouldn't be my first choice.

There are bits for drilling through tile as well as diamond coring bits which have already been mentioned.

[BobFish]

There are bits for drilling through tile as well as diamond coring bits which have already been mentioned.

This is what I've used

[Kobiyashi]

Try using a diamond grit tile coring bit, they go as small as 1/4” basically the same bit for drilling bulkheads in our tanks except tiny diameter-wise. Should do the trick just remember to flush the hole with water to keep the core clear and the bit cool.

Edit: methodology of drilling is important. Lubricating the “cut” as well as keeping the drill bit cool. High speed, low feed or low speed high feed. Feed rate = amount of pressure you apply during the cut. If you have tried this already then I guess check geology websites that may have some insights we don’t have.. I’ve seen core samples that have been taken from granite that use a diamond cobalt coring bit and they use a lot of drilling fluid. Try Rapid-Tap, you can get it from Acklands-Grainger

[Ya Dude]

Try using a diamond drill
LOL

[BobFish]

please close this thread it is a year old