Problems using your rock saw will occur at some point when slabbing rough. Pay attention to any unusual high pitch sounds during the sawing process. If this occurs, immediately shut the saw off. Check to see if the rock has shifted and is loose or if the blade is getting coolant. When the saw is turned off, note the duration and length of spin of the saw blade when turning off the saw. If the blade doesn't spin freely, and instead comes to an abrupt halt, then the blade could be in a bind. This occurs when the rock shifts in the vise and pinches the sides of the blade against the saw keft or when the blade becomes dull. When the blade becomes dull and requires sharpening (cleaning) or when the saw blade and carriage are out of alignment, any of these problems should be remedied before sawing resumes. A sharp saw blade is essential when sawing very hard or dense gemstones. When the blade needs sharpening, no need to take the rock out. Use a blade dresser or a piece of an old grinding wheel and clamp it to a board and attach this board to the vise ahead of the rock and in line with the diamond saw blade. Small "C-clamps" are handy for this procedure. (A blade dresser for saw blades is listed under LAPIDARY SUPPLIES.) If you clamp the blade dresser at an angle so that it will clean both sides of the saw blade, and then reposition the dresser for the next slab, so that little of the dresser is used, the dresser will last a long time. (Throw these small pieces of grindstone or blade dresser into your tumbler for the rough grind stage. The grindstone pieces can be placed in the sun for a while to drain any oil reserves then rinsed in hot water and soap before adding to the tumbler.) Make sure your "C-clamp" will clear the top of the saw hood before closing. Several minutes of sharpening is all it takes. We leave the dresser clamped on the vise, for hard or metallic material, which demands that the blade be sharpened with each slab cut. REMEMBER: use wooden wedges for an odd shaped rock (almost every rock) to securily hold your rock in the vise to prevent it coming loose or starting to slip, and SHARPEN REGULARLY especially for agate, jasper, metallic material, etc. For tips on sawing round rocks see Assorted Lapidary Tips. If your slabs are dish shaped or your slabs seem to be fracturing, more than likely, your blade is dull. If the saw blade is dished it will need to be sent to the manufacture for repair. Repair is not available on every saw blade. Contact us for any questions. For more tips on using your slab saw see Slab Sawing Guidelines.