collapse

Author Topic: Drilling agate  (Read 4793 times)

harryopal

  • ALF'er Gold Member
  • *
  • Posts: 231
    • Email
Drilling agate
« on: September 02, 2015, 10:57:12 AM »
Good morning rock hounds,


I have just left a message with Aussie Lapidary and am awaiting a call back. Meantime I would be interested in the experience of others with drilling agate, jaspers and hard stones.


I drill holes in polished cabs and stuff I get from African to make pendants for my handcraft shop. I have used core drills 1/2 ml up to 2 ml buying drills from reputable suppliers but am frustrated at how difficult it has been to find bits that really drill well. I used to use my dremmel but now have a bench press to accomodate a hand drill but still without making much impression


I would appreciate any thoughts on this. Thanks in anticipation.


Yours tropically, Harry ???
harryopal

roho

  • ALF'er Bronze Member
  • *
  • Posts: 16
    • Email
Re: Drilling agate
« Reply #1 on: September 04, 2015, 09:59:35 AM »
hi,  i am new to this forum.  my first post here.
i have been doing a lot of drilling of agate and jasper.  i always drill them before doming.  i find that helps with my accuracy.  there is also usually a little blow out when the drill comes through, if the doming is done after the drilling then you can get rid of blow out quite easily.  it is possible to drill from both sides to try and meet in the middle to avoid the blow out but this can be tricky to line up - it is my preferred method however. 
as for the actual drilling i use a drill press.  i use diamond coated drill bits.  the best source i have had is old diamond drills bits from my dentist (that have been sterilized of course).  i found that providing a pendant to my dentist helped greatly with the supply of bits.
i drill under water and do so very slowly, with minimal pressure and frequent in and out and washing out.
works really well, but the harder the stone, the more difficult.

harryopal

  • ALF'er Gold Member
  • *
  • Posts: 231
    • Email
Re: Drilling agate
« Reply #2 on: September 04, 2015, 10:52:02 AM »
Good morning Roho,


Thanks for your posting. A bit more experimenting with the drill press and I find that I have been guilty of probably the most basic mistake of using too much pressure. And I do drill in water. A very light touch with the drill press and a bit more patience (Not easy for an impatient person) and this morning I got through a jasper and another stone with which I had previously had problems.


As for blow outs, I find it helps to first provide a small pilot hole. I use masking tape across the top of the stone where I am drilling and mark the spot with ink. The tape prevents the drill slipping at the start and making a mark.  There may be a small blow out with the small hole but this is lost when then moving to the  larger bit. I enter part of the way on the back side and then flip the stone and complete the hole from the front. The small hole means there is no problem lining up with the larger bit.


This morning I drilled the jasper just using the larger bit and found that with both sides of the stone taped hotthirsty hotthirsty [size=78%] and light pressure there was no blow out. [/size]
harryopal

Jimnyjerry

  • Global Moderator
  • ALF'er VIP
  • *****
  • Posts: 2603
  • balts pingvins
    • Email
Re: Drilling agate
« Reply #3 on: September 04, 2015, 11:10:31 AM »
Roho welcome to ALF  :)
 
You might like to look at http://aussielapidaryforum.com/forum/index.php?topic=4097.0
 
It has links to other discussions.  As well have a look at what Mick B has done with drilling on his posts.
 
Some people also use hollow core drills .
 
Enjoy the site  :)
I try to take one day at a time, but sometimes several days attack me at once.

roho

  • ALF'er Bronze Member
  • *
  • Posts: 16
    • Email
Re: Drilling agate
« Reply #4 on: September 04, 2015, 01:11:02 PM »
thanks,
i really like the masking tape idea.  i will have to give that a try!

Aussie Sapphire

  • Administrator
  • ALF'er VIP
  • *****
  • Posts: 3335
    • Aussie Sapphire
    • Email
Re: Drilling agate
« Reply #5 on: September 04, 2015, 01:43:47 PM »
Hello Harry,


Sorry, I dont think we have returned your call yet - for some reason, the phones, emails and orders have been crazy this week and we have been having trouble keeping up.


Yes - definitely, slow and steady is the main thing here.  All the other things you are doing look fine.


Mick B has had some success using Sintered Carving burs (small ones) instead of drill bits for doing holes in hard material.  As most drill bits are electroplated, the sintered ones tend to hold up better over time (more expensive but last longer) - it is still important to go slow with the drilling for best results though.


There are also triple ripple bits - we dont stock them but some customers like those.  Might be worth a try for you.  We do stock core drills - some customers like those in preference to the twist drills.  Seems to be personal preference though.

If we can assist further, please email or call (email is probable better as we can work on those over the weekend).

cheers
Leah
Aussie Sapphire - The Lapidary Warehouse

southerly

  • ALF'er Gold Member
  • *
  • Posts: 221
    • Email
Re: Drilling agate
« Reply #6 on: September 04, 2015, 09:58:13 PM »
Harry,

I use a mix of small ball shaped diamond bits and core drills. The balls last longer as more surface edge is cutting and there are not sharp corners where the diamond is easily lost. I have never burnt out a ball bit, I have Burt out lots of core drills but they are cheap.
I also often start a small hole with a small drill size and work my way up. Michael Burgess has used and like the triple ripples, I have not tried them yet.
David

mick B

  • ALF'er Platinum
  • *
  • Posts: 322
Re: Drilling agate
« Reply #7 on: September 05, 2015, 10:47:43 PM »
Drilling agate and other stones in the 7 plus hardness range can be challenging, as a carver drilling is a very important step in the process, I use small ball points, triple ripples, and cores, I also have a set up in a drill press that I sometimes use, but now mostly drill the gem free hand in water. I drill in from both sides with very careful placement, no blow out, drilled these today for a friend, agate, tiger eye, nephrite jade, prehnite, rhodonite, only around 5 minutes to drill the agate, I drill at around the 400 grit final sanding stage, the blue gem is gem silica I cut for a customer in Singapore, 7 hardness.
« Last Edit: September 05, 2015, 10:51:14 PM by mick B »

harryopal

  • ALF'er Gold Member
  • *
  • Posts: 231
    • Email
Re: Drilling agate
« Reply #8 on: September 08, 2015, 02:31:00 PM »
Good afternoon Rock Hounds,
 
Thank you to Roho, Jimmynjerry, David, Leah and Mick B for your responses to my drill questions.
 
May all your holes be free from blowouts.  (No pun intended.)
 
Yours tropically, Harry
harryopal

Tags:
 

Recent Activities

Flint by Agate Head
[Today at 04:51:34 PM]


Cabbing wheel water feed by Mouse
[May 10, 2021, 09:18:52 AM]


International Faceting Challenge. by Faceting Frank
[May 08, 2021, 09:58:28 PM]


LED Ring Light by Faceting Frank
[May 07, 2021, 08:18:37 PM]


12.7mm shaft Vertical machine by MakkyBrown
[May 07, 2021, 09:34:58 AM]


Shaping Cabs on a Flatlap by Buch Metter
[May 06, 2021, 07:19:55 PM]


MB Faceting Machine Build by MakkyBrown
[May 05, 2021, 11:37:43 PM]


faceting machine digital microscope setup by Faceting Frank
[May 04, 2021, 06:23:36 PM]


Trip Advice by tinker
[May 03, 2021, 10:32:13 AM]


Jewelers spectacle magnifiers by MakkyBrown
[May 01, 2021, 08:51:12 PM]


opal enthusiasts? by harryopal
[May 01, 2021, 06:40:41 PM]


Sapphire cabbing diamond wheels by MakkyBrown
[April 30, 2021, 02:21:00 PM]


DIY Cabbing Machine by Faceting Frank
[April 29, 2021, 10:21:56 PM]


Facetron wandering dial indicator issue by RoughCreations
[April 27, 2021, 11:11:04 AM]


Halls Mark 3 by Dihusky
[April 25, 2021, 06:08:45 PM]