Machine Drilling Stone

 

For hundreds of years, stone was cut from the earth by hand.  It was a slow, labor intensive process that limited the size of blocks that could be quarried. Vertical holes were drilled around the block of stone to be removed.  At the bottom of the block a row of horizontal holes was drilled.  The holes were filled with water and wooden plugs were driven into the holes.  As the wooden plugs absorbed the water, they swelled and lifted the block of stone free from the earth.  A good worker could drill 25 lineal feet of 12-inch to 24-inch holes in one day.  Deeper holes would require three men. Their output was generally 40 to 50 feet per day. 

In addition to the drilling method, channeling was practiced in many marble quarries.  Through the Civil War, channels were cut by hand simply by swinging steel picks against the stone until the stone was worn away.  The greatest depth a channel could be cut was about eight feet.  At this depth the channel was only six inches wide, just room enough for the stone cutter to place his foot one in front of the other as he moved forward.

Channel cuts would generally run perpendicular the joints in the stone.  Spacing would be set to produce a minimum number of joints in the blocks.  Most marble deposits had one system of joints that was prominent with only a few cross joints.  Channeling was then done at right angles to the prominent joint system.  The joints would then be used to help make the cross breaks. Also, by making the cuts at right angles to the direction of rift or grain, splitting by drilling and wedging was made easier.

In 1863, the Wardell Steam Channeler was introduced in Vermont. A cam lifted a gang of bits and then allowed them to drop of their own weight upon the stone.  The Channeler traveled back and forth on a track cutting a channel 2 to 3 inches wide and up to 12 feet in depth.

Originally operated by a steam boiler, theWardellChanneler was soon expanded to have cutting heads on both sides of the track.  This allowed the cutting of two channels at once.  A further improvement eliminated the steam boiler and uitilized an electric motor.  While being limited to only vertical cuts, the cost of operation per square foot of channel cut was dramatically less than manual labor.

Sullivan and Ingersoil soon developed channelers that featured swinging heads that could be tilted to any angle, allowing machine horizontal cuts for the first time.  Sullivan channelers used diamond core drills which improved greatly over the hand drills.  Diamond prices, however, rose too high to make the drills cost efficient.

 

By the 1920s electric-air machines took over requiring only a 15 H.P. motor compared with a 40 H.P. boiler for steam channelers.

 

 

P is t o n d ri lls, weighing 300 to 400 pounds and using two men could cut 150 lineal feet of drill holes per day. Powered by compressed air, they were used primarily for drilling the deeper holes. .                       These piston drills were mounted on columns to work at an
                                       angle following the incline of the stone bed.

With the introduction of the lighter weight hammer-type drills, weighing only 35 to 40 pounds, only a single operator was needed.  He could cut 200 feet of drill holes per day.  410 feet drilled in just 10 hours was the record! Easily handled, hammer drills, run with compressed air, were used for smaller, shallow or medium depth holes.

Used for horizontal drilling, these hammer drills can drill up to 10 feet deep.  Each machine can drill 288 lineal feet of hole into marble in six hours.

 

Drill holes averaged 1 to 1 inches in diameter.  Spacing of the holes would vary from 4 inches to 2 feet apart. By drilling in the direction of the rift, the holes could be spaced further apart while taking advantage of the ease of splitting following the grain.

Almost all larger quarries utilized channelers to some extend.  Equipment and operation were expensive.  Drilling was less expensive and was almost always used for floor cuts.

 

Source: Through the Ages, Vols. 2 & 8.

[Home] [Tools] [Machine Drilling]