How Dimensional Natural Cleft Flagstone Is Made

Flagstone Quarry Block

Check out this quarry block.  If you click the image on the right  it will enlarge.    Notice the saw up on the upper block.  After the soil and overburden rock is removed from the block with dozers and TNT, a saw like this is used to cut a 2′x3′ grid on the block.  Next a skid steer with forks will pop up 2′x3′ cubes from the quarry floor.

Splitting Flagstone

Next the skid steer stands the cubes on end.  As you can see in the picture, natural cleft flagstone has seems running through it.  These are know as reeds.  Using a chisel, workers at the quarry whack the reeds and split the block into natural cleft flagstone.  After the 2×3’s are split, the stone will be graded for thickness.  Unlike thermal treated flagstone, natural cleft flagstone has a variance in thickness.  Usually the variance is 1/4″ in either direction.  So when we say 1″ natural cleft, we mean natural cleft flagstone that is between 3/4″ to 1 and 1/4″ thick.  After the flagstone is split it needs to be refined.  Some stones will have portions with major defects like surface blemishes,  cracks, wedging and breakage.  We need to bring the stone to the re-cut table where we resize the flagstone.    See the picture below Click the link to see the usual sizesflagstone is re-cut to.  One inch  thick  natural cleft

Re-cut Saw Resizes Natural Cleft Flagstone

flagstone is used for stone laying applications that call for cement while 1.5″  thick flagstone is usually laid on various aggregate bases.

Learn How Natural Stone Steps are Fabricated for Your Landscaping and Masonry Projects

Saw Rock For Cutting Bluestone Treads

This Saw Rock was recently drilled at a flagstone quarry just after the quarry blasted off the overburden rock with TNT and just before being split from the quarry block.  Next it was loaded on a truck and bound down to the flatbed floor with chains and binders, transported to the fabricating saw shop, and set down on the ground where it is waiting to be picked up and loaded in front of a computer controlled  gantry saw with a six foot, diamond tipped circular cutting disk.

Python Gantry Saw Getting Loaded

When the stone is brought into the shop  it is placed on dun-age and in front of the python gantry saw’s blade.  The blade often needs its diamond tips to be re-tipped,  This process however,  is for another  article.  The saw in this picture  has a freshly tipped blade installed so cutting will soon begin.  This is a wet saw, so once cutting begins water will be flying every where.  The stone dust that is created is harmful to the environment, including streams, wildlife and fish.  The water will turn the dust to mud which will be channeled through a reservoir system that is built into the fabricating shop.  Later the harmful mud will be pumped into a lined pond located outside the building  where it will be of no harm to the environment.

Gantry Saw Cutting Tread Material

Once the saw begins cutting  the fabricators can take a break and let the saw do its work.  This  saw is cutting at two inch increments.  It begins sawing at 1/4 of an inch from the top of the block and every time it makes a lengthwise pass it drops 1/4 of an inch.  Once it saws to the bottom, the blade lifts back to the top, moves over 2″ and and begins the process again. This slab should take 2 or 3 hours to cut and then the fabricators can move on on to the  next slab.  Once cutting is done it is important to get to thermal treating immediatly.  Thermal Treating works well when the stone has been thoroughly soaked and as you can see the gantry wet saw above does a fine job working the water into the stone.

Burning Tread material For Landscapes and Indoor Masonry Projects

Attempting to thermal dry stone leads to popping cracking and destruction of the stone material. Oxygen is the fuel used to thermal the stone surface.  Once all of the proper conditions are met the thermal process puts a natural stone finish on what was previously a sawn finish.  This material can be re-cut for many different applications like patio flooring, pool coping, indoor or outdoor steps, pier caps, wall caps, hearths, mantles and more.  Profiling techniques such as radial cuts, bullnosing, easing, and rock facing are a few of the techniques used to improve the workmanship and appearance of this type of natural stone.

Re-cutting Natural Stone Treads To Size

More about these techniques will be discussed later.  After the stone is cut to size for length it will be neatly stacked and banded on a pallet.  There you have it. Now you know how gauged natural stone material is fabricated. This gauged tread quality flagstone material is different from natural cleft flagstone which is usually sold with variance in thickness.  My next article will address natural cleft quarrying.  Thanks for reading.  I hope you learned allot.  Check out more at: http://www.landscapingstone.us

Palletized Blue Natural Stone Treads

Gantry Saw Cutting Treads

Check out  this gantry saw cutting through a 2′ thick piece of bluestone.  This large chunk of bluestone was drilled and split from a quarry block, then transported to this saw shop where it will be sliced into 2″ thick increments.   Later it will be removed to the re-cut saw where it will be re-cut to length.  Some treads like the ones pictured here are palletized with a sawn finish and others are thermal treated. Both Thermal Treated dimensional and broken irregular patio and walkway stones are made with a  gantry saw like this as well.  In Pennsylvania the bluestone treads material comes as “blue” or “Variegated”.  Varigiated tends to have allot of blue and brown in it.

Natural Cleft Methods

Sawn Finish Methods

Thermal Finish Methods

Dimensional pattern flagstone has either sawn edges or spapped edges depending on where the stone comes from. Some quarries use a mechanical guillotine to snap the edges off of broken flagstone and others saw flagstone cubes from the quarry floor and the hand split the cubes. Snapped edges have a rougher hand cut or old world look while sawn edges are more refined look. Either way you can lay your flagstone on cement or an aggragate base.

Dimensional Flagstone vs. Broken Flagstone

Dimensional Flagstone is always square or rectangular and the various sizes most often cut include: 1×1s’, 1×8s”,1×2s”, 18×18s”, 18×30s”, 18×3s’, 2×2s’, 2×30s” and 2×3’s. 2×3s’ are the most sought after size. Most flagstone quarries produce mixed pallets of these flagstone sizes.Below are 2×3’s from Pennsylvania.

Dimensional-Bluestone

Broken Flagstone is also often refered to as “Stand-up”, “Irregular” or “Random”. Its best to refer to this type of stone as broken. Some people confuse the the terms irregular or random to mean mixed size dimensional flagstone. Below you will find Broken Flagstone From Arizona. The color of this stone is buff.

Broken Arizona Buff Flagstone

Natural Stone Finishes

(Natural Cleft,  Sawn and Thermal)

Natural Cleft Finished Stone is the most rustic old world looking of the the three finishes.  It comes dimensional or broken.  Click on the image below to get a closer look.   If your looking for old world style, you should also look into rock faced edges for your Natural Cleft Flagstone.   Natural Cleft Flagstone requires more time to install,  since the fabrication techniques at the quarry and the nature of natural cleft stone are less refined than the other finishes.  Natural cleft stone is hand split.  Therefore, thickness of the stone is not exact.  ”One inch stone” could be anywhere from three quarters of an inch to an inch and a quarter thick generally.  When buying natural cleft stone you will want to know exactly what your thickness tolerance variances will be.

Natural Cleft Broken Pennsylvania flagstone

Sawn Finished Flagstone is easier to install since it has been sawn on all sides and is therefore gauged for thickness.  Sawn stone is almost always dimensional.  It is often used for patio, treads steps, coping,  sills or veneer.  It has a very classical, institutional and architectural feel.  Dimensional limestone is usually sawn.

Sawn Finish Limestone treads with a rockfaced Edge

Thermal Finished Flagstone is nothing more than sawn stone that has been blasted with water and a special torch.  The thermal process crackles the  sawn finish into a more natural looking finish.  This stone has gauged thickness.  This process is done most often to pennsylvania bluestone.  Below is a piece of variegated bluestone.  Click the picture to get a close look.  This finish is achieved in both dimensional and broken flagstone.

Broken Thermal Flagstone