Drilling Rock

[bk_market]

Im planning to drill my liverock this weekend. Anyone have experience doing this before? Im planning to use 1/2" drill bit. Is this too big? will it shatter the rock? any tip advice on drilling or selecting drill? Thanx

[YBeNormal]

Yes I've done it before and no, 1/2" is not too big as long as your rocks are wider than 1/2" (just kidding).

 

I drilled very porous LR using old drill bits designed to drilling wood. If the rock is very dense, you'll need to use a bit designed for cement. Avoid using a hammer drill unless the rock is very large and dense. Even then you still might split the rock in the process. I placed larger rocks on a bucket of sand when I drilled them. The sand helped hold the rock stable and absorbed some of the vibrations.

 

Take your time and it should work out fine.

[fab]

Drill slowly, not fast. Use a relatively low rpm.

 

fab

[bk_market]

hmmm i have mix comment on the drill speed

 

I got 3 people tell me that drill as fast as i can otherwise the rock will break but also another 3 advise me to drill slowly.

 

Not sure what should i do

[phisigs79]

i would think faster would be better. I think this because if the bit got alittle snag the torque of the drill at faster speeds would go through it no prob. Now if you go slower it might put alot of stress on it when it snags and crack the rock in half. I done this once and it worked for me.

Edited August 24, 2007 by phisigs79

[fab]

Experiment with a piece of rock. Discover for yourself what works best with the particular rock you have to work with.

 

Different types of live rock come from different source islands and have different physical properties from each other. Some rock is denser other rock is less dense. Some rock has very low tensile strength, being held together by calcareous growth. So the inherent binding strength of the rock will depend on the type of live rock you are working with. Be sure your drill bit is sharp so it does not 'snag.' The try a piece of rock drilling fast. If it breaks up, try another hole drilling slow. Extra holes in the rock will not cause a problem because the rock will be overgrown eventually with live stuff and the holes can be plugged with rock fragments that will not show after a while.

 

fab

[flowerseller]

hmmm i have mix comment on the drill speed

 

I got 3 people tell me that drill as fast as i can otherwise the rock will break but also another 3 advise me to drill slowly.

 

Not sure what should i do

 

So try it on medium speed

[bigJPDC]

Good luck and be prepared for anything - I have shattered a big piece and also made nice frag mounts in a piece 1/4" thick somehow. Remember it's pretty much the exact opposite of using a drill press on a flat piece of wood. I used a spade bit but am guessing the YB's call on the masonry bit is the best.

[davelin315]

Regardless of the RPM, I would think that what makes the biggest difference is whether you put too much pressure on it. If you go faster you will take off smaller chunks of rock at a time as long as you push slowly. Same with slower RPMs. Either way, if you push too hard, you'll most likely crack the rock.

 

I would use a masonry but, too. My own preference (never having drilled rock but having bought a bit for it) is a masonry bit or comparable bit. Wood bits are not as hard as masonry bits and every bit will lose pieces of metal as it bores into the materials. Masonry bits should minimize the amount of metal that gets into your water. Also, the tip is shaped differently as are the grooves.

[lanman]

Regardless of the RPM, I would think that what makes the biggest difference is whether you put too much pressure on it. If you go faster you will take off smaller chunks of rock at a time as long as you push slowly. Same with slower RPMs. Either way, if you push too hard, you'll most likely crack the rock.

 

I would use a masonry but, too. My own preference (never having drilled rock but having bought a bit for it) is a masonry bit or comparable bit. Wood bits are not as hard as masonry bits and every bit will lose pieces of metal as it bores into the materials. Masonry bits should minimize the amount of metal that gets into your water. Also, the tip is shaped differently as are the grooves.

 

I agree - higher rpm's on the drill bit, but s-l-o-w on pushing it through the rock.

 

bob

[bk_market]

thanx guys

 

i also need to drill a 1/2" hole on a acrylic plate. Any advice on drilling a hole on acrylic? what kind of drill bit for these?

Thanx

Edited August 25, 2007 by bk_market

[lanman]

thanx guys

 

i also need to drill a 1/2" hole on a acrylic plate. Any advice on drilling a hole on acrylic? what kind of drill bit for these?

Thanx

I haven't drilled anything that small; but I just used a regular hole saw; part of a kit. Regular drill bit sticks out of the center of the larger circular bits. Seemed to work fine for me.

 

bob

[davelin315]

When drilling acrylic you need to watch out for the acrylic that is being removed. I tend to use higher speeds but the problem with this is the bit heats up faster and then melts the acrylic as it's drilled out and the bit can then stick. Make sure you clean it off or keep it cool as you drill. I wouldn't use a normal bit as you're more likely to crack it. Use a hole saw or use a different kind of bit designed for boring holes in materials. The smaller the teeth the better if you use a hole saw.

[NRehman]

Drilling pilot holes with smaller bits avoids many stress fractures. Use a couple of bits to build up to the size you want. This will work for the rock as well as the acrylic.

[Grav]

I agree - higher rpm's on the drill bit, but s-l-o-w on pushing it through the rock.

 

bob

 

 

I agree with Bob.

 

In general I find working porus LR about the same as soft pine. The very dense stuff as hard as cement. You can drill it with anything from a spade bit up to mason bits.