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Tool Corner

All about tools for the stone carver.

The Tool Column - Oil That Hammer - July/Aug 2003

My first “power tool” for sculpting was an angle grinder fitted up with a masonry grinding disc. It seemed an amazing step from the serenity of hand tools to the dust and noise of machinery, and yet the allure of power had touched me.


At a Camp Brotherhood Symposium workshop, I learned about fret cutting and bought a turbo diamond blade that still seems so indispensable for roughing out forms. I also watched the figurative carvers dance their carbide chisels in and out of tight spaces on voluptuous marble forms.


In another arena, granite gods and goddesses with bushing tools were contouring, texturing and anointing salt and pepper obelisks and spires. Maybe it was the beauty of the sculpture, or perhaps the romantic notion of historic production (air hammers have been around for over a century) that coaxed me over to the demo booth. I nervously plugged a pneumatic hammer into the air hose and attacked a piece of white marble with a 3/4 inch, 3 tooth chisel. Plug in your earplugs, suck the straps down on the goggles and snap some new filters into the respirator; I am hooked! Of course I bought one - a big one. And yes, quite a few chisels too.

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Tool Column - Stone Fired Furnace - Nov/Dec 2002

 

Hand tools, yeah! One arm swings the hammer; the other braces the point or claw. This drum beat sends us on a journey into the stone. It’s primitive, direct, a linking of human spirit to the earth itself. It’s that pulse and flow, that ancient meter that pushes deeper into the stone, producing a connective rhythm, a groove getting closer to form. Hand tool Junky! The purist quietly smiles, the power junky searches for yet a bigger blade (yes, I did buy the big saw).


And yet, even the simple steel chisel or point requires some maintenance.  Sharpening the edge with a hand stone suffices for a while. A bench grinder corrects even more. Eventually the edge or point is worn beyond the quick fix and the tool no longer functions for us. We brace up the credit card and look for the favorite tool store to give us another chance, another dancing partner with a special kind of magic, at a price of course.


But Wait! Remember those halcyon days of yore, you and your comrades gathered around Camp B, sparks rising through the air as a bellow handle spins the coal fire to life.  Alphonso directing, his shouts like Latin lyrics over the harsh metallic clave from Chuck-o’s two handed power swing. The pavilion jumps to their tempo. A writhing bar of plastic metal changes shape. A transformation, “scrap” to “tool” in just a few blows. It is the magic of fire, my friend: the forge.   I’ve assisted this process, built the fire, turned the handle, danced with joy when it all went right. A forge can allow us to repair, modify, or custom create the tempered steel tools used in stone sculpting. Fueled by propane or coal, the forge creates enough heat to anneal, shape, and temper tool steel. My enchantment goes back to childhood memories of turning the blower handle for grandfather, while he worked some magic with various metals.


I was recently gifted with a small farm forge, similar to the one used at Camp B and by my grandfather. Hard, low sulfur coal is available at a Chehalis heating supply. A small kindled wood fire builds up enough heat to start the coal burning. Place additional pieces around the perimeter of the fire pan, so the heat will drive off impurities and begin the coking process. It takes about an hour to get a good coal fire going. Coal forges should be fired outdoors. They emit noxious fumes.


A great way to take a break from the studio on a crisp winter day! I will be putting together an article reviewing heat-treating procedures in the future. There is a wonderful website for anyone interested in building or using a forge.  http://www.anvilfire.com  has pages full of plans, projects, discussions, tools, links to other sites, coal sources, tutorials, etc. . . . Friendly smiths, farriers, and metal work artisans offer the sage advice. They have some interesting discussions on safety that are applicable to stone workers.

 

Tool Column - Time for a Bigger Saw?- Sept/Oct 2002

Early summer saw a number of NWSSA members at a granite seminar organized by Hank Nelson and hosted by Judy and Kirk McLean. I ambitiously bring forth a 1200 lb piece of Fraser River salt and pepper. Envisioning the Rites of Spring joyously filling the ears and large fuzzy bumblebees tumbling around the cushy and aromatic centers of large peonies in a sun filled garden is as easy as sitting on the patio beside Judy’s ecstatic flower garden. Transforming this granite block into a garden seat resembling a peony blossom, luring the casual stroller to sit and smell the fragrance of the Season . . . the sculptor is the eternal optimist!

The 7 inch angle grinder that diced and sliced so easily on a Sierra white granite lantern is shamefully slow in parting ¼-inch deep cuts in this hard Canadian stone. Clearly it is time for a more efficient tool.

I query seminar participants and begin the search; larger blade, more power, water for cooling continuous cuts and reducing dust. It’s a good list. I remain adverse to combining water and electric if personal contact is involved, so consider an air- or gas-powered tool. Later, I talk with construction trades, rental shops, query the web and yes, I discuss it with my wife.

The search continues. Tom Small carries a new gas-powered 14-inch cut-off saw into Camp Brotherhood. Connecting to the water hose, he apologizes for the well-worn blade . . seems he broke in the saw removing enough granite to gravel an average driveway. The saw fires easily with a compression release. The 20-pound tool balances nicely as I begin a flat cut to about 5 inch depth. Quarter roll the boulder. Follow the kerf for guidance and continue around the stone. Sweet! The hook is set!

Several manufacturers produce gas-powered cutoff saws with similar specifications: 70cc, 4.5 hp, 20 lbs, 14 inch blade(5 inch cut), water cooled cutting, prefiltered air cleaner, decompression starting, reversible cutting arm, ergonomic design, vibration damping. Similar prices around $900 for the saw and $200 to $300 for the 14” diamond blade. Oh yeah, and another $30 for some good hearing protection, ‘cause none of these guys are proud enough of noise levels to publish them. The gloves, goggles and respirator are already in my toolbag, inspiration is pushing me out the door. I’m thinking, I hear a saw in my future.

Tool Column - Angle Grinders - July/Aug 2002

A workhorse in any stone studio, the standard 4 to 5 inch angle grinder spins up around 10,000 rpm.  This is pretty much designed speed for metal and masonry cutoff and grinding discs.  Diamond blades and cup wheels for dry operation are engineered for this speed and rely on the higher rpm for proper cooling.  Silicon carbide cups, Zec discs and similar abrasives are rated at the higher speed, but perform smoother and longer around 5000 rpm.  Finishing and polishing materials are happier around 3000 rpm.  So, three different uses at three different speeds; go buy three different grinders?

The frugal stone carver soon discovered that plugging into a router speed control would let one grinder do an adequate job at three different speed requirements.  The router speed control works similar to a fan rheostat or a light dimmer.  Moving a dial varies the amount of a.c. current available to the connected device; less current means less power and slower rpm.  So really, what you get is a variable power grinder that runs fast under no load and slows down to some slower speed dependent upon how hard you push on the stone.  Tool manufacturers saw $$$ in the demand for this flexibility and incorporated the handful of electronics for current control into “variable speed” grinders. Despite their shortcomings, these are a viable all-around tool.  Hang on tight when you hit the start switch.  Ease onto the stone for slower speed operations.  Pay attention to what the attachment is doing on the stone and vary pressure accordingly to control the speed.  After a while it all seems normal and you don’t even consider getting along without one.

Enter a new breed of grinders; advertised with “electronic speed control maintains desired speed under load”.  These are a grand step forward in multi-function tools.  They use an electronic feedback circuit to monitor the shaft rpm and vary the current to hold the speed steady regardless of the load (well, at least within the current/power rating of the tool). Dialing up a speed, like setting a cruise control, lets the sculptor attend to form and technique with less distraction imposed by the tool. Smooth operators they are, with repeatable and consistent performance during cutting, grinding, shaping and sanding. A few models also use the electronics to reduce the current for sudden drops in rpm, like wedging a disc in a corner, thus preventing motor burnout and reducing damage to attachments.  Some also incorporate “soft start” features, slowly and smoothly bringing the tool up to speed instead of instantly torquing against the hands and wrists.  Most of these new grinders have some type of shaft clutch to protect the gears and the sculptor from kickback caused by serious jamming.

If you are in the market for a new variable speed grinder, or maybe you’re just another tool hog like me, check these new machines out.  They don’t have much history.  They do seem to perform at a level different from their predecessors.  I’m interested in any feedback? Oh, yeah . . .gloves and goggles and muffs, oh yeah. Mail/email your comments to us at NWSSA.