The best "bits"?

[Rockette]

Hi all. I have searched the forum but can't seem to find an answer to my question "what are the best drill bits for my purpose".
Santa brought me a Dremel 3000 with a Flexi shaft and I have the jaw chuck for tiny bits. (Seems Santa shops at Bunnings  )
I just want to drill holes for jewellery. 0.8 to no bigger than 2 mm. No carving or engraving or fancy stuff yet, just holes. Most of my rocks are Quartz or agate so pretty hard stuff.
I have had a go with some solid diamond plated bits I got from the craft shop but Hubby is not sure they're the best bit for the job. I went thru 3 bits to drill 5 holes. The stones were all about 3 to 4mm thick.
So my question to you experienced rock drillers - what's the best bit? Core, twisted, triple ripple, solid? I see that triple ripples are twice the price of the others but if they last more than twice as long then that's ok.
Any and all advise welcome. Thanks in advance.

[FlashGP]

I have a couple of diamond plated twist drills for enlarging holes in stones.  they cost me about $35 from AJS and are 1mm and 1.2mm.  The 1mm drill has cut a few holes but is wearing.


We always use hem in a water bath.  Are you drilling under water or dry? Drilling dry will wear your bit out really fast.


regards
Flash.

[Rockette]

Yes, always in a water bath. I have a bowl of water with a wooden block in the bottom of it. The water comes about halfway up the shank of the drill bit when submerged.

Do you know anything about triple ripples? They look like the go but are expensive.

Thanks for your reply

[Jimnyjerry]

Here is a list of discussions on drill bits
http://aussielapidaryforum.com/forum/index.php?topic=5586.msg50173#msg50173http://aussielapidaryforum.com/forum/index.php?topic=5752.msg51646#msg51646
Our club uses core drill bits Jerry

[Rockette]

Thank you, jimmyjerry. I'd did look all through the posts that came up when I searched for drilling, including your links, but none had any comparison on the different bits for different jobs.
I've looked at some US sites and FlashGP's reply so I now get that twisted bits is for enlarging holes.
I would love to know what's best - core, solid, or triple ripples for my purpose of .8 to 2mm holes in agate and Quartz that are about 3 to 4mm in thickness.

[sapphireminer]

The Triple Ripple bits are very good when drilling start off with a small pilot hole then increase in stages to the size you want eg .75mm first then maybe 1.2mm  , 1.7mm , 2mm as the bits are very fine  treat them very carefully and keep cool and wet. A Dremel  is hard to drill with as you tend to have it spinning when putting the bit to the stone can dance around a bit a flex shaft I find better as the bit is stopped when placing on the stone and  you can start the bit turning very slow. You can use a ball bur smaller than your finished hole size to make a small dimple to help start the bit in the right spot.
Dave

[harryopal]

Agates are not easy to drill. I used to import carved stones for a shop and was amazed at the work done with small agates and the predrilled holes which were often small and still took a bit of work to enlarge them.


I would suggest if you are intending to do a bit of agate or stone drilling you buy a basic hand held drill and a drill press. Some of the basic drills are now reasonably cheap and you can buy drill presses which will hold your drill. Good quality presses are around $100 plus but you can buy cheap ones that will do the job.


Here's a link to what I mean. https://www.ebay.com.au/i/172380186208?chn=ps


As suggested, drilling any stones it is a good idea to have a water container in which you hold the stone so that it doesn't get too hot and your are not inhaling dust which is very unhealthy. There is always the tempation to press harder when the process seems slow but you will wear out your bits very quickly. A light touch and patience is needed and drill press and drill will make the processes somewhat easier. I tried a variety of drill bits and there was no great stand out. Another point is to begin on one side and then before you have reached the other side hold the stone up to a light so that you can see the hole from the other side. Mark the spot and then continue from the other side. If you just bore straight through a stone you may get a 'blowout" when the drill comes through. Good luck.

[Jimnyjerry]

Sorry forgot to mention to use a drill press. Will be busy for an unknown time on urgent family matters.

[FlashGP]

Harryopal had a good point about the dust if the work is not kept wet. 


There's currently an outbreak of silicosis in Qld among the Stone Masons cutting and finishing stone bench tops.  I can't believe they have been doing this dry, especially with re-constituted stone.


I heard one press report of 27 cases in a hand full of work shops, enough for the Minister to ask for a ban on imported re-constituted stone. 


It surprises me that is the only reported action, I would have expected the Workplace Safety Officers to be treating these workplaces the same as a workplace handling hazardous materials.


I'm also awaiting to see if there will be criminal prosecutions under the WHS laws or the outcome of civil claims relating to a foreseeable danger to the worker's health, that could have been avoided using cheap wet cutting and grinding techniques.


Regards

[Aussie Sapphire]

Harryopal had a good point about the dust if the work is not kept wet. 

I'm also awaiting to see if there will be criminal prosecutions under the WHS laws or the outcome of civil claims relating to a foreseeable danger to the worker's health, that could have been avoided using cheap wet cutting and grinding techniques.


Regards

Exactly - this is an entirely foreseeable risk.  Unbelievable that the standard operating procedure would not involve wet cutting AND appropriate PPE.

cheers
Leah

[harryopal]

Unfortunately there is a bit of a macho tendency amongst a lot of men including tradespeople who should know better to feel that there is something sissy about protective gear. And of course it is not particularly comfortable wearing a mask. I recall watching tradesmen working, without masks and with clouds of dust, cutting pavers to size when laying the footpaths in the Townsville Mall. And many years ago watching a fellow without a mask spraying pesticides in the family pineapple plantation.


For most lapidarists plenty of water is usually adequate for small scale drilling, cabbing and so on.

[Rockette]

Thanks for the replys, everyone. I think I'm going to get an assortment of bits and try them all to work out what works best for me.
I am doing all that you sugest, water bath, PPE, drilling halfway then from the other side to avoid blow out, starting slow and angled, using the Dremel Flexi shaft, being patient and not using pressure.
I don't use a drill press but there is one in the shed I can use if I need to.
I really just wanted advise on the different types of bits so I don't waste money by buying ones that I don't need.
Thanks.

[Giel]

Ask your dentist...

My dentist gave me hundreds of old diamond drill and carving bits for free.
Only small sizes though 

Drilling will not be faster, but cheaper.

If you want your new drills to last; go slow! especially on the smaller sized drills

[Rockette]

Thanks for the tip, Giel.
Now I need to go to the dentist