O&MM Fabricator - November/December 2017 - 37

ALL PHOTOS CREDITED TO: BRIDGETOWN FORGE

Left image: Proper ergonomic grip of hammer. Middle image: Hofi hammer with its signature compact head and rounded peen.
Right image: A relaxed grip makes for more efficient hammer striking.

the people and things interact most efficiently
and safely." The International Ergonomics
Association defines it as "concerned with
the fit between the user, their equipment, and
their environment." However you define it, it's
basically about using the techniques that allow
you to get the most out of your equipment with
the least risk of injury.
The term has been around for a while. It
was first proposed by Prof. Hugh Murrell at
a 1949 meeting of the British Admiralty and
officially codified in 1950. While it is often
used interchangeably with 'human factors,'
ergonomics still carries the same meaning;
an efficient interaction of human and object
to reduce wear and tear on the human.
In the fabrication world, the name most frequently associated with ergonomics is Uri Hofi,
a blacksmith from Israel. He has developed a
system that derives the maximum results from
the minimum of physical effort. Hofi himself
is a testament to the efficacy of the system.
Although in his 70s, he is remarkably hale and
continues to put in long hours at his forge in
Ein Shemer, which is in the Shomron region
of Israel. People who have seen him forge
all claim that he has a preternatural ability
to move metal. Arnon Kartmazov, who owns
Bridgetown Forge in Portland, Oregon, will
readily attest to that.
Kartmazov served an apprenticeship with
Hofi in 1985 in Jerusalem. He also served
apprenticeships in Japan for 12 years, eventually opening his own smithy in Northern Kyoto.
While people have long been using various
aspects of Hofi's approach, Hofi was the one
who gathered it all together and codified it
into his own technique. "He's very observant,"

Braided steel handles on top tools transfer less shock to hands while using power hammer.

notes Kartmazov. "He notices everything, so
he learns fast. If the feedback is good, he
adopts it. Hofi says, 'Don't talk, show me. If
it's better, I'll use it.'"
So there is a thread of commonality to all facets of his approach. It's all aimed to obtain the
maximum results from the minimum effort. This
not only saves wear and tear on the smith, but
saves time by getting the most from each heat.
"Metal is a hard material, and you can't
work it at room temperature," says Kartmazov.
"If I was on planet Mercury, I wouldn't have
this problem. I could work it with my fingers.
But here, the steel doesn't wait; it won't stay
hot for very long."
Now, consider the basic equation. K = MV²/2,
where K is kinetic energy, M is mass, and V
is velocity. You can see that increasing mass
would increase the power of a blow. But heavier
hammers are trouble. Striking a 4 lb hammer

hundreds, if not thousands, of times a day will
wear out your muscles and ligaments. "A bigger hammer wears on you. You either damage
yourself or lose control. A 3.5 lb hammer is a
good compromise." Fortunately, there are two
ways in the above equation to skin a cat since
there are two variables in the denominator. So
we can keep the mass constant and instead
increase the velocity. That is, swing the hammer faster.
Hofi's technique addresses this in both the
shape of the hammer and the manner in which
you hold it. But the main theme is lighter and
looser. "A tighter grip results in cumulative
damage to you because it makes a greater
energy transfer from the work to the hand to
the elbow, and so on," explains Kartmazov.
The result is a flowing approach to the work.
"Metal, at high temperatures," says Arnon, "is
flowing. You should be, too. You can't be rigid."

November/December 2017 * O&MM Fabricator | 37



Table of Contents for the Digital Edition of O&MM Fabricator - November/December 2017

President’s Letter
Letter From the Executive Director
NOMMA Network
NOMMA Education Foundation
First Look: 2018 Metalfab / Fencetech Attendee Brochure
It's in the Air
A Fabricator’s Ergonomics
Seven Costly Management Mistakes
Supplier Members
New & Returning NOMMA Members & Iron Club Members
Gold Members
High-Tech Laser Machine Allows Business to Boost Productivity and Expand Product Offerings
Index of Advertisers
O&MM Fabricator - November/December 2017 - intro
O&MM Fabricator - November/December 2017 - cover1
O&MM Fabricator - November/December 2017 - cover2
O&MM Fabricator - November/December 2017 - 3
O&MM Fabricator - November/December 2017 - 4
O&MM Fabricator - November/December 2017 - 5
O&MM Fabricator - November/December 2017 - 6
O&MM Fabricator - November/December 2017 - 7
O&MM Fabricator - November/December 2017 - 8
O&MM Fabricator - November/December 2017 - 9
O&MM Fabricator - November/December 2017 - 10
O&MM Fabricator - November/December 2017 - President’s Letter
O&MM Fabricator - November/December 2017 - 12
O&MM Fabricator - November/December 2017 - Letter From the Executive Director
O&MM Fabricator - November/December 2017 - 14
O&MM Fabricator - November/December 2017 - NOMMA Network
O&MM Fabricator - November/December 2017 - NOMMA Education Foundation
O&MM Fabricator - November/December 2017 - 17
O&MM Fabricator - November/December 2017 - 18
O&MM Fabricator - November/December 2017 - First Look: 2018 Metalfab / Fencetech Attendee Brochure
O&MM Fabricator - November/December 2017 - 20
O&MM Fabricator - November/December 2017 - 21
O&MM Fabricator - November/December 2017 - 22
O&MM Fabricator - November/December 2017 - 23
O&MM Fabricator - November/December 2017 - 24
O&MM Fabricator - November/December 2017 - 25
O&MM Fabricator - November/December 2017 - 26
O&MM Fabricator - November/December 2017 - 27
O&MM Fabricator - November/December 2017 - 28
O&MM Fabricator - November/December 2017 - 29
O&MM Fabricator - November/December 2017 - It's in the Air
O&MM Fabricator - November/December 2017 - 31
O&MM Fabricator - November/December 2017 - 32
O&MM Fabricator - November/December 2017 - 33
O&MM Fabricator - November/December 2017 - 34
O&MM Fabricator - November/December 2017 - 35
O&MM Fabricator - November/December 2017 - A Fabricator’s Ergonomics
O&MM Fabricator - November/December 2017 - 37
O&MM Fabricator - November/December 2017 - 38
O&MM Fabricator - November/December 2017 - 39
O&MM Fabricator - November/December 2017 - 40
O&MM Fabricator - November/December 2017 - Seven Costly Management Mistakes
O&MM Fabricator - November/December 2017 - 42
O&MM Fabricator - November/December 2017 - 43
O&MM Fabricator - November/December 2017 - 44
O&MM Fabricator - November/December 2017 - Supplier Members
O&MM Fabricator - November/December 2017 - 46
O&MM Fabricator - November/December 2017 - New & Returning NOMMA Members & Iron Club Members
O&MM Fabricator - November/December 2017 - 48
O&MM Fabricator - November/December 2017 - Gold Members
O&MM Fabricator - November/December 2017 - 50
O&MM Fabricator - November/December 2017 - High-Tech Laser Machine Allows Business to Boost Productivity and Expand Product Offerings
O&MM Fabricator - November/December 2017 - 52
O&MM Fabricator - November/December 2017 - Index of Advertisers
O&MM Fabricator - November/December 2017 - 54
O&MM Fabricator - November/December 2017 - cover3
O&MM Fabricator - November/December 2017 - cover4
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