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Sawing Technology
Monday | 11 February, 2013 | 10:43 am

Throw the hammer down

By Nick Wright

At Tru-Cut Saw, the mastery of sawsmithing is passed to next generation

February 2013 - It’s no secret that a skills gap is plaguing U.S. manufacturers. Although manufacturing activity is gaining traction, there still aren’t enough peoplein the pipeline with the chops, interest and qualifications to fill jobs. But the employment figures obscure an equally vital issue that belies the skills gap: the dying art of mastering a trade.

Bucking the trend is 24-year-old Thomas Otter at Tru-Cut Saw Inc., Brunswick, Ohio. There, he keeps the sawsmithing tradition alive, honing his senses over CNC skills. Late in 2012, he began a five-year apprenticeship under his uncle and Tru-Cut owner David Otter, and his father, Alan Otter, production supervisor. 

The company manufactures saw blades from 200 millimeters to 3 meters in diameter for cutting ferrous and nonferrous material. However, every circular saw blade needs some straightening and tweaking to get a level plate. Using a repertoire of cold working methods, Thomas uses differently weighted hammers to pound out thick or thin spots for a balanced profile, ensuring proper tension of the blade when it slices through metal. It’s not an easy job, as it demands both muscular and mental moxie. When he gets home at night, he sleeps well.

Before Thomas started hammering blades, his uncle and father made sure to indoctrinate him with some basics.

“We’re first teaching Tom how to swear,” David jokes. “We tell him he has to learn on the bad blades and warped material first. It’s a part of the apprenticeship to learn how to swear.”

In actuality, the first thing Thomas did for the first two weeks, before he was allowed to strike any blades, was get control of the hammers. His uncle set up Thomas with scrap saw bodies coated in a thin mineral oil so when he struck them on the anvil, Thomas could see the shape of his hammer blows where the oil scattered.

mm-0211-webex-hammer-image1“Once we felt comfortable that he got the control over two or three different weights, we moved him slowly into the heavier plate and it seems to be working out well,” David says. “I figure I give him another five years and he’ll have arms like Arnold Schwarzenegger.”

Thomas currently is working on 1/4 inch, 1/2 inch and 3/4 inch thick blades in diameters of 28 inches, 32 inches and 42 inches.

The hammer heads weigh from 1.5 pounds to 15 pounds and have a variety of twisted, angled faces depending on what type of modification the blade needs. Balancing hammer weight, desired blade form and tempering the blow isn’t easy, Thomas says.

“The weight of them, trying to find the right spot where to hit it is probably the hardest thing so far,” he says.

A family fraternity

Thomas’ sawsmith regimen is based on the English Sawsmith Society guidelines—the same set David and Alan mastered in England before coming to the United States and eventually starting Tru-Cut in 1981. There are only about 500 master sawsmiths remaining in the world, David estimates.

Tru-Cut also gets blades in for service and repair. Not only is Thomas mastering flattening, he’s also learning  how to check the runout, says Alan. Runout is how “true” the blade runs in a circle. It’s checked with a dial indicator while the blade is mounted on a spindle.

“This will tell us where the movement of the blade is, whether it’s plus or minus 0.0010 thousandths or 0.0020 thousandths. Whichever way it’s going, we mark it, take it off, check it with a straight edge, flatten the high spot and check the runout again. If it’s minus, we know we have a hollow section,” says Alan. The less runout, the longer and smoother the blades will run.

Sawsmiths apply different working methods, depending on the blade’s alloy. For example, some of the plates measure 62 on the Rockwell hardness scale. Those are high-strength steels that can’t be struck with a hammer, David says.

“But we have a peen hammer that has a carbide insert in the edge and it’s ground to a V shape. The way we strike the body puts a little cut mark in.” If there’s a hollow section in the blade, the peen (or pecking) hammer will draw it flat.

Throughout the course of the next few years, Thomas will sharpen his touch, sight and sound, using the blade’s peen and cymbalic tone to determine its characteristics. These skills go back hundreds of years, originating from hot blacksmithing and forging.

“The cold forging redistributes the molecules in base steel, making sure there aren’t too many molecules in one position, which can cause the blade to twist or warp like an airplane propeller,” David says. This is what sawsmiths, as Thomas is learning, try to eliminate.

“It means a lot to me that my uncle and dad have been doing it for so many years,” Thomas says. “Hopefully if I have kids one day, I’ll pass it along to them and keep the tradition going.” MM

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