2017 International Forest Industries Magazines April May 2017 | Page 50
Productivity is essential to a
successful operation in the forestry
and recycling industries, which is
why it’s important for companies
to continuously seek out ways to
simplify machine maintenance,
according to Matt Eul, Marketing
Specialist with Vermeer’s Recycling
and Forestry division.
“For horizontal grinders and
whole tree chippers specifically,
the chip drum and its knife style
can have a dramatic impact on
performance, as well as the amount
of time needed to perform routine
maintenance,” he told International
Forest Industries.
Babbitt versus non-babbitt
knives
Dull knives can cause unnecessary
wear to the machine and
inconsistency in chip sizes, which
is why regularly sharpening the
jobsite.
While non-babbitt knives can
reduce maintenance times, many
traditional non-babbitt knife
designs will require additional
maintenance time as the knives
work their way out of place during
operation, and potentially coming
into contact with the shear bar.
Developing better solution
In 2013, Vermeer set out to develop
a better non-babbitt knife style.
Through research and testing,
Vermeer identified and corrected
common issues companies
working in recycling and forestry
applications were experiencing.
In the typical non-babbitt knife,
the two push screws are placed on
the back of the knife and threaded
in-between the bolts that clamp
the knife down. This configuration
allows the blade to “work out”
when processing certain materials,
Eul said.
Jeff Bradley, product manager
at Vermeer: “When Vermeer
started to explore converting to
It may seem like a small detail for many people,
but we understand how important knife design
is to the overall performance of a machine and
how labor-intensive making adjustments and
sharpening can be
Jeff Bradley, Vermeer
knives is important. However, not
all manufacturers use the same
style of knives.
It is common for manufacturers
to use babbitt knives on their
machines, often requiring the
use of a ladle, bench vice, torch
and lead file to aid in resizing
and sharpening a set of knives.
This work requires a trained
professional and often will have
to be done in the shop since the
process involves working with
molten metal.
Non-babbitt knives are another
style offered by manufacturers.
Instead of using molten metal, non-
babbitt knives add length to the
knife using two push screws on the
back of each one. When sharpening
and adjusting the knives, the user
simply adjusts the push screws,
which can be performed on the
Visit us on
Stand 492
The state-of-the-art chipper knives within
the Vermeer units
a non-babbitt style knife on chip
drums, we wanted to make sure
our customers would benefit from
the switch.
“We knew the labour necessary
to adjust the size of the knives after
sharpening would be significantly
reduced, and there was a benefit
of no longer having to work with
molten metal.
“However, the problem of
knives working out of place during
the processing of large, hard
materials remained an issue. Our
testing determined that working
out of place could lead to the
knives contacting the shear bar,
which could cause significant
damage to the knives and shear
bar.”
Vermeer developed a solution
to this problem by relocating the
screws to line up with the bolts
that clamp down the knives. This
alignment prevents the knife from
working out because the end of the
screws protrudes into the knife slot
and butts up to the clamping screw.
Vermeer’s WC2500XL increases productivity and reduces maintenance
48 International Forest Industries | APRIL / MAY 2017
Placing the screws in line with
the bolts also allows the screws
to act as a shock absorber in the
instance the knives encounter
a contaminant. Instead of the
knife absorbing the damage from
hitting a foreign object, the shank
of the screws sticking out of the
knife body will buckle, helping to
minimize the damage.
All Vermeer grinders and whole
tree chippers utilize this patented
non-babbitt knife design in the chip
drum mechanism to better meet
the needs of recycling and forestry
professionals.
“It may seem like a small
detail for many people, but
we understand how important
knife design is to the overall
performance of a machine and
how labour-intensive making
adjustments and sharpening can
be,” adds Bradley.
“The non-babbitt knives on
Vermeer grinders and whole tree
chippers will help keep you up and
running.”