Build A Giant Rock Saw

You can build a giant slab saw for monument and masonry work out of easily acquired parts and materials. Many of the parts and materials can be salvaged: junked lawnmowers, washing machines and dryers, the list is long and even some car parts lend themselves to building custom machine tools like mudsaws and other stuff. For this project you will need a piece of steel bar, some pillow block bearings with attendant shaft stock, scrap lumber, and a few nuts, bolts, and screws. Threaded rod is good stuff also, and comes in very handy during this project as well as others. And you will need a standard 1725 RPM washing machine/dryer motor, 1/4 or 1/3 horsepower.
The blade of this machine is a steel bar of the type used in spring suspensions of vehicles. The steel is about 1/4 inch thick, and about two or three inches wide. The length must be determined by you, but around 36" is good enough to get some fairly large sized cuts. The actual weight of this blade facilitates the cutting of the rock, as abrasive is fed to it while it moves back and forth in a reciprocating motion. It is not a speed machine by any means, and should only be used in its presently explained config for softer materials like onyx, sandstone etc.. Greater efficiency can be had, but at a price. Weighting the blade can add to speed, but lugs the motor. The next mud saw I build will be chain driven by a gas motor, like a lawnmower motor. Then a lot of weight on the blade will not be a problem and it will cut a lot faster than an electric motor can. Overall, this project is worthwhile if you can employ it, because large diamond saws run into the hundreds of thousands of dollars. If you can accomplish the same thing, albeit more slowly, for a hundred bux or less (A LOT LESS!), that is an advantage par excellence, and the extra time taken becomes a minor problem. Steady does it with this saw, and as long as your mechanical set up is durable, and the abrasive/water feed runs properly, you can do some amazing things with a mudsaw, not least of which is to make some major dollars. Tiles and building stone of odd materials bring really good money.
Once you get the hang of using your mudsaw, you will discover all sorts of methods and trix to make your life easier, and make your work more productive. Stonework is one of the very oldest arts, and the selection of stoneworkers tools is extensive: chisels, drills, snips, hammers; all can be used to good effect. Find a book called STEREOTOMY and read it. After this book of course. You will be glad you did. Right now I will give you the basic idea, which then should be modified to your particular needs.
Like any lapidary equipment, the SLIDING BAR saw, or Mud Saw, works through abrasion. Its because of this that it is called a mudsaw. The abrasion process creates a lot of ground up rock which gets mixed with the abrasive slurry, and the end product of the cutting can only be called mud. You will of course want to restrict use of the mudsaw to the outdoors. It really comes in handy in the GREAT outdoors, like when you find an outcrop of stone where you can leave your saw, and cut on site. The steel bar of your mudsaw is just the carrier and weight for the abrasive, which is generally silicon carbide grit, in about 80 to 100 size. Quartz or garnet sands work on softer materials as well. Two things you have to get right on this saw, are the blade guides, and the drip feed. A few ideas are given here, and it pays to experiment around somewhat, once you get your saw done, to see what worx best for you.
The first order of business in getting a mudsaw up and running is to build a mechanical step down of the motors speed, so that it decreases the usable speed of the 1725 RPM to about ten percent or so of the actual motor speed. You will want a very small pulley on the motor shaft, and 2 very large pulleys afterwards. Optimum speed for the mud saw is 25 reciprocations per minute. You will have to experiment, and that can go up or down a little (RPMs) and still work fine. Say between 20 RPM and 35 RPM, with lower speeds being better. Sometimes you can get small heavy duty high-torque low-speed motors like are used on hospital beds, and do away with a lot of the rigmarole of building a step down set-up. Here is the step down unit I used first, and it worked fine, and was not too hard to build.


You will attach the stepped down motor power to a disk of heavy plywood, and bolt the bar blade to it in a bearing type arrangement, so as the disk turns, the blade moves back and forth. Diagrams here are a must, and explain it better than I could in many words: