O&MM Fabricator - March/April 2018 - 27

"When you bend thick metal in a Hossfeld, the metal generally
cups for two reasons. The first reason is because the metal has been
stretched and compressed while it was being bent. The second reason
is the distance between the roller or bending-block in the swing arm
from the mandrel the metal is being bent around."
Reason #1: Stretching and Compressing
Francis continued, "When bending metal, the metal on the inside
of the bend, the ID, compresses; and the metal on the outside of the
bend the OD stretches. When bending thick metal in a Hossfeld, and
the OD is stretching in the direction of the bend, the stretching metal
pulls metal in from the sides (sketch #2). This pulling lifts the sides as
they are being sucked in toward the center.
"And, while the metal is being bent, the inside ID is compressing.
This compression forces the excess metal out sideways, making the
rectangular stock wider around the ID (sketch #3).
Hazel, still looking somewhat perplexed, said, "France, I still need help
understanding this. If the OD is stretching and the ID is compressing, does
that mean I base my metal cut length on the centerline of the metal?"
Francis replied, "I wish it was that simple, but it's not. We need to
run some test pieces, but here is what I've been told."

"Fine-tuning a Hossfeld, when beyond the bender's capabilities,
is done with steel wedges or steel shims. I have been told that if
you put a roller in the swing arm and a thick flat stock shim filling
the gap in between the roller and metal to be bent, the cupping in
a bend will be greatly reduced (sketches #4 - 6). The thick metal
shim does not get bent. I've never done this, but see no reason why
it will not work.
"The teardrop-shaped dies Hossfeld sells are shaped like teardrops
so that the long side will hit against the metal, preventing the arbor
from rotating with the swing arm and axle.
"Hazel, if you're going to make bends with a heavy metal shim around
one of the remnant fabricated dies in the shop, you'll need to tack-weld
a wedge-shaped leg on the die so it mimics the Hossfeld's teardrop and
doesn't rotate. If the arbor rotates, then metal will be pulled in from
the left side of the bender, negating the use of the back-stop you've
adjusted for positioning the multiple pieces."
The look on Hazel's face seemed recharged. You could almost hear
the plan in her mind being formulated. Hazel is quick. Francis continued,
"I wish I could be more specific about bending, but I only know a little
about all the tooling in the shop. The people who use the tools, like
yourself, know the ins, outs, and specifics of each tool.
"I have to run now because the forklift died for some unknown
reason. Later today, when you have a process worked out for your
parts and I've got the forklift back in action (knock on wood), I hope
you'll give me a bending lesson.
"I hope the steel shim and 30 percent neutral zone information will
be helpful. Good luck."

The Neutral Zone
"When cold bending steel, the OD stretches easier than the ID
compresses. There is an area in between the stretching OD and compressing ID called the Neutral Zone.
"The center of the 'neutral zone' is used when calculating the cut
length of the steel that will be bent. The neutral zone centerline for
calculating purposes is located in 30 percent of the metal's thickness
from the edge that will be compressed."
Reason #2: The Bending Method
"Hossfeld benders are popular because they're versatile. A Hossfeld
can perform many bending operations. However, what is not engineered
into a Hossfeld is fine tuning for all bending situations.
"In our large Hossfeld (#2 model), the holes in the swing arm are on 1
and 1/8" centers. The closest a Hossfeld comes to fine tuning inside the
bender, not on top of the bender, is by moving and rotating the bending
blocks. The holes in the bending blocks are offset, so by rotating the
bending blocks we can alter the space in between the bending block and
the arbor in approximately quarter inch increments. The 1 and 1/8" hole
spacing in the swing arm synchronizes the block locations, so the 1/4"
spacing increments run consistently for the full length of the swing arm.
755845_Ken.indd 1

March/April 2018 * O&MM Fabricator
| 27
7/13/15 5:40 PM


http://www.haberleusa.com http://www.broboUSA.com http://www.haberleusa.com

Table of Contents for the Digital Edition of O&MM Fabricator - March/April 2018

President’s Letter
Letter From the Executive Director
NOMMA Network
NOMMA Education Foundation
2018 Top Job Winners Showcase
Laminated Glass Railing: New Requirements and Pointers for a Successful Installation
Francis & Hazel
The Tax Cuts and Jobs Act
NOMMA Member Savings Program–Metalfab Update
Supplier Members
New & Returning Nomma Members & Iron Club Members
Gold Members
Take a Stroll Down Memory Lane - Nomma’s First Years, Part Ii
Index of Advertisers
O&MM Fabricator - March/April 2018 - Intro
O&MM Fabricator - March/April 2018 - bellyband1
O&MM Fabricator - March/April 2018 - bellyband2
O&MM Fabricator - March/April 2018 - cover1
O&MM Fabricator - March/April 2018 - cover2
O&MM Fabricator - March/April 2018 - 3
O&MM Fabricator - March/April 2018 - 4
O&MM Fabricator - March/April 2018 - 5
O&MM Fabricator - March/April 2018 - 6
O&MM Fabricator - March/April 2018 - 7
O&MM Fabricator - March/April 2018 - 8
O&MM Fabricator - March/April 2018 - President’s Letter
O&MM Fabricator - March/April 2018 - 10
O&MM Fabricator - March/April 2018 - Letter From the Executive Director
O&MM Fabricator - March/April 2018 - NOMMA Network
O&MM Fabricator - March/April 2018 - 13
O&MM Fabricator - March/April 2018 - 14
O&MM Fabricator - March/April 2018 - 15
O&MM Fabricator - March/April 2018 - NOMMA Education Foundation
O&MM Fabricator - March/April 2018 - 17
O&MM Fabricator - March/April 2018 - 2018 Top Job Winners Showcase
O&MM Fabricator - March/April 2018 - 19
O&MM Fabricator - March/April 2018 - 20
O&MM Fabricator - March/April 2018 - 21
O&MM Fabricator - March/April 2018 - Laminated Glass Railing: New Requirements and Pointers for a Successful Installation
O&MM Fabricator - March/April 2018 - 23
O&MM Fabricator - March/April 2018 - 24
O&MM Fabricator - March/April 2018 - 25
O&MM Fabricator - March/April 2018 - Francis & Hazel
O&MM Fabricator - March/April 2018 - 27
O&MM Fabricator - March/April 2018 - 28
O&MM Fabricator - March/April 2018 - 29
O&MM Fabricator - March/April 2018 - The Tax Cuts and Jobs Act
O&MM Fabricator - March/April 2018 - 31
O&MM Fabricator - March/April 2018 - 32
O&MM Fabricator - March/April 2018 - 33
O&MM Fabricator - March/April 2018 - 34
O&MM Fabricator - March/April 2018 - NOMMA Member Savings Program–Metalfab Update
O&MM Fabricator - March/April 2018 - 36
O&MM Fabricator - March/April 2018 - Supplier Members
O&MM Fabricator - March/April 2018 - 38
O&MM Fabricator - March/April 2018 - New & Returning Nomma Members & Iron Club Members
O&MM Fabricator - March/April 2018 - 40
O&MM Fabricator - March/April 2018 - Gold Members
O&MM Fabricator - March/April 2018 - 42
O&MM Fabricator - March/April 2018 - Take a Stroll Down Memory Lane - Nomma’s First Years, Part Ii
O&MM Fabricator - March/April 2018 - 44
O&MM Fabricator - March/April 2018 - Index of Advertisers
O&MM Fabricator - March/April 2018 - 46
O&MM Fabricator - March/April 2018 - cover3
O&MM Fabricator - March/April 2018 - cover4
https://www.nxtbook.com/naylor/NOMS/NOMS0518
https://www.nxtbook.com/naylor/NOMS/NOMS0418
https://www.nxtbook.com/naylor/NOMS/NOMS0318
https://www.nxtbook.com/naylor/NOMS/NOMS0218
https://www.nxtbook.com/naylor/NOMS/NOMS0118
https://www.nxtbook.com/naylor/NOMS/NOMS0617
https://www.nxtbook.com/naylor/NOMS/NOMS0517
https://www.nxtbook.com/naylor/NOMS/NOMS0417
https://www.nxtbook.com/naylor/NOMS/NOMS0317
https://www.nxtbook.com/naylor/NOMS/NOMS0217
https://www.nxtbook.com/naylor/NOMS/NOMS0117
https://www.nxtbook.com/naylor/NOMS/NOMS0616
https://www.nxtbook.com/naylor/NOMS/NOMS0516
https://www.nxtbook.com/naylor/NOMS/NOMS0416
https://www.nxtbook.com/naylor/NOMS/NOMS0316
https://www.nxtbook.com/naylor/NOMS/NOMS0216
https://www.nxtbook.com/naylor/NOMS/NOMS0116
https://www.nxtbook.com/naylor/NOMS/NOMS0615
https://www.nxtbook.com/naylor/NOMS/NOMS0515
https://www.nxtbookmedia.com