Spencer Lapidary Blog

Get a Life from Your Diamond Drill Bits!

2009-07-16T23:22:00.000-07:00

Tina & I get asked all the time about drilling rocks, slabs and gemstones. Most questions concern the problems people experience while trying to drill with diamond drill bits and not having very good results or life from their expensive bits.

First ask yourself a couple of questions. Are you using sintered or plated diamond drill bits? At what speed are you drilling? Are you withdrawing the drill bit often to allow for flushing and cooling?

Sintered diamond bits have the diamonds mixed directly into or embedded in the steel tip. As the metal tip wears down, new diamonds come to the surface. Sintered diamond drill bits tend to hold up better than plated diamond drill bits; however, they are initially more expensive. The life of any type of diamond drill bit depends upon the hardness, abrasiveness and thickness of the material being drilled and the specific drilling techniques used (drill speed, pressure and lubrication), however, the diamonds of a drill bit don't actually wear out as much as they wear off due to heat and friction caused by the extreme hardness and abrasiveness of the material drilled. Plated diamond drill bits tend to shed their layer of diamonds more easily and you are soon left with nothing but a blunt steel rod with which to drill.

SPEED KILLS: Reduced drill speeds, low drill pressure and increased use of water lubrication will extend drill bit life considerably.

We DO NOT recommend drilling metal. When you drill metal with a diamond drill bit, the metal will build up on the diamond drill bit covering the diamonds that actually DO the cutting for you. You CAN NOT dress a diamond drill bit with a grinding wheel, because the diamonds on the drill bit are harder than the grinding wheel. About all you may accomplish is to knock off more of you precious diamond particles. Sintered diamond drill bits have a much thicker layer of diamonds so that when one diamond is knocked out in the drilling process, the one below with take its place.

Tina & I find that we are able to drill dozens of holes by following the rules below.

Use a good quality sintered diamond drill bit if you can afford them.
Drill only hard rock or glass, no metal.
Drill at fairly slow RPMs.
Use lots of water as your coolant.
Withdraw the diamond drill bit from the hole often to allow the fresh cooling water to flow in and flush out the waste material.
Use a small drill press. You'll put less stress on you diamond drill bits and your hands by using a drill press rather than hand drilling using a flexable shaft or electric drill.

Happy Rock Drilling!

Tina & Mark Bennett

Citron (aka Lemon Chyrosprase)

2009-05-28T03:25:00.000-07:00

Citron, also know as Lemon Chrysoprase, is a lemon to light lime colored form of Chrysoprase. Citron (Lemon Chrysoprase) varies from AA grade (without any matrix material) to B grade (with brown to gold matrix webbing). Our Citron A is Light Lime Green in color with no Matrix material & our Citron w/ Matrix is a beautiful lemon yellow with brown to golden matrix webbing - Both are from South Africa.

Chrysoprase is one of the rarest and most valuable of the chalcedonies. Its green color comes from nickel; the color can fade, and in a moist environment may also recover. Larger broken pieces are often fissured with irregular colors. Chrysoprase often occurs as nodules or in crevices in nickel deposits.

Chalcedony is the cryptocrystalline variety of quartz, meaning the crystals are too small to even be seen by a microscope.

TMB Jewelry's Web Store - On It's Own!

2009-05-27T14:17:00.000-07:00

Tina & I have begun moving TMB Jewelry to it own location on the web at www.tmbjewelry.com so that our jewelry customers can find it a little easier than at the Spencer Lapidary site. We hope that everyone will like the new look and feel that we are trying to give TMB Jewelry's website. You can still see our jewelry at http://www.spencerlapidary.com/, but feel it tends to get a little lost in the rock shop. Please feel free to send us some comments on what you think!

Tina & I have also begun development work on new lines of jewelry that we really want to make including a line of hand stamped jewelry to go along with our healing stone mixes that we created. This new line will have everything from bracelets to rings that are hand stamped and can be fully personalized by YOU for YOU! We're very excited to be able to branch out and begin work that we have wanted to do for so long now.

Hope everyone had a safe Memorial Day weekend!

Best Regards - Tina & Mark Bennett