How to Cut Large Rock Slabs

One of the many things you can create out of a rough rock is a slab. A stone slab is flat with varying thickness that is mostly used in paving floors, creating tabletops, covering walls, etc.

Buying a big rough rock and cutting it yourself is practically cheaper than buying pre-made slabs. Come to think of it, you can cut a lot of slabs and sell some that you don't like.

Method and equipment to use

While a lot of rock cutters use tile saw for cutting, this is not advisable when dealing with harder materials like agate. You'll end up getting saw blade marks on your slab.

Out of all the methods of cutting a big rock, using a diamond slab saw is the best and the standard. For producing larger slabs, you need a bigger saw. An 18-inch slab saw will probably be the smallest in the selection, with 36-inch being the largest you can use.

Choosing your diamond blade

There are three common types of diamond blade you can use in rock cutting: segmented blade, continuous rim blade, and notched rim blade.

A continuous rim blade is often used when you're cutting a more precious rock, since it produces less kerf. [kerf - the width of the material that is removed through cutting/grinding]

A segmented blade is great for cutting precious and semi-precious rock. This type of blade gives precise cuts.

Notched rim blades are usually used in production cutting. This blade is rigid and has a thick core, thus it can withstand demanding production. However, this blade doesn't cut as precise as the other two blades mentioned above. So if you're looking for a blade to cut dozens of slabs per day and precision doesn't matter as much, you can go with a notched rim blade.

Cutting the rock

One of the advantages of using a slab saw is its hooded feature, which means that your cutting process will be less noisy and messy. You can set up your rock on the saw and just leave it running until the slab saw automatically shuts off.

When you're using a slab saw, or any type of lapidary machine, make sure you know how to operate it. It's great if your saw comes with a manual, as some equipment tend to be particularly technical when you first set it up. Generally, here are the steps of the cutting process:

  1. First thing to do is loading up the vise with the material. Make sure that the vise is cranked tight, where the rock can't move even a slight inch. This is important, especially if you're cutting a larger material. A loose vise and moving rock may damage your blade.

  2. Next, adjust the crossfeed and align your material to your saw blade, depending on how thick you want your slab to be. A crossfeed is a mechanism where you can move your vise to the left or right using a revolving handle.

  3. Put down the hood of your saw, press the safety interlock switch on, and let your saw do the rest of the cutting.

Watch this quick live demonstration using a Highland Park Lapidary slab saw: