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Here is an article I wrote which was published in The Trapper and Predator Caller magazine pertaining to adjusting large conibears. The purpose of this adjustment is to eliminate or drastically reduce the number of otters and beavers caught by the hind quarters in large body grip traps. As I approached a very productive beaver
set one drizzly January day a
couple of years ago, I noticed the set area was torn up a great deal.
Once at
the set, I saw where a long struggle had taken place. All that remained
was an
empty #330 body grip. The set consisted
of a #330 placed in a well-worn channel below a beaver dam. This
channel connected two beaver ponds and
was a hot location. Upon closer inspection, I saw the unmistakable
tracks of an
otter in the soft mud on a nearby bank made during its struggle.
This set had been the best producer at this
site, accounting for several beavers. During the process of resetting
the trap,
I remembered that this specific trap had caught two otters earlier in
the
season, and I remembered that both otters were caught far back on their
bodies,
just in front of the hind legs. I was able to recall with certainty the
history
of this specific trap because a spring had broken on it a month and a
half
earlier, and I had to replace that spring. When I replaced the spring,
it no
safety catch, because it was lost when the spring broke. I had no
replacement
safety catches, so I fashioned one out of a piece of small-diameter
rod. This
homemade safety catch was different in diameter and length than the
factory catch,
and it stood out. I decided to pull this body grip,
take it
home and try to determine why it was performing so poorly on otters. I had another #330 nearby that was not
producing nearly as well, so I moved it into the better location where
I had lost
the otter. Once home, I inspected the trap
and found
that it appeared to be in very good shape. The jaw rivets looked good,
the jaws
weren't bent, the springs were plenty strong, the dog looked good and
so did
the trigger. I was baffled. Next I tried a function test. I
compressed
the springs and put on the safety catches. While squeezing the jaws
together
with the dog and trigger on top, I rested the bottom jaws on my
workbench. I
pulled the springs down so they were in contact with the bench, which
caused
the safety catches to slide down and stay fully engaged with the
springs. While
grasping the upper jaws on the set body grip, I used a wooden stake to
push on
the trigger. Right away I noticed that the trigger had six to eight
inches of
play. Once I encountered resistance, I kept pushing the trigger with
the stake.
To my amazement, the triggers moved in an arc to almost a parallel
position to
the bench before the trap fired. (The trap didn't completely fire
because I
still was holding the jaws with my hand.) Now I knew why the otters were getting
so
far through the trap before it fired. I also was having some trouble
with
catching beavers farther back on the body. I've had other incidents
where I had
poor holds on otters in other traps, but I didn't know which traps they
were.
After my discovery, I inspected all of my #330s and #280s right away. In the past, I had attributed poor holds
on
otters to the animals' remarkable swimming speed. I thought they were
simply
torpedoing through the trap before the trap could fire to get a decent
hold. I
also thought the poor holds resulted from otters' ability to slither
around
trigger wires. I had experimented with the different types of bends in
the
trigger wires and even put a wire between the ends of the trigger
wires, to
make it impossible for an otter to slither around the trigger. While
this
improved the holds to some extent, I was still having too many holds
way back
on the otter. Now I knew why. I knew the key to correcting the problem
was in the dog and trigger, so I examined them closely. I found the
excessive
play in the trigger was because the dog didn't seat all of the way into
the
trigger notch. The trigger moved freely because the flats of the dog
weren't in
contact with the bottom of the trigger notch (See Figure A).
To reduce the play, use a round file to
deepen the grove in the dog (See Figure B). File just enough metal away
to
allow the flats of the dog to come in contact with the bottom of the
trigger
notch (See Figure C). This eliminates
the play in the trigger. Because the dog groove is deeper, the dog has
to move
farther upward to disengage from the jaw. This causes the trigger to
have to
travel even farther before the trap fires.
To correct the excessive trigger travel,
its
necessary to do some more filing. Using
a flat file, make a bevel on the forward side of the dog groove (See
Figure B).
This will cause the dog to have to move less to disengage from the jaw.
File a
little at a time, testing the travel of the trigger frequently.
Ideally, I like
to have the trigger move about one to two inches for the trap to fire.
This
does not cause a hair trigger because it still takes the same amount of
pressure to move the triggers, but they don't have to travel as far. For this adjustment to be the most
effective, I recommend the bolt-on or riveted type triggers be used.
I've found
that the four-way triggers are very difficult to get consistent results
from
while using these adjustment procedures. All of my body grips were
adjusted as
described above, and all but one of the otters I caught last winter
were held
from just behind the head to the front shoulders except for one. This
one
exception was caught in a #330 that had the four-way trigger installed,
and the
otter was caught just in front of the hind legs. I've found this condition
primarily on
older, used body grips, but have had to adjust some new ones. I haven't
had any
experience yet with the Species Specific type of body grip, so I can't
say how
the trigger travel is on it. It's a good idea to
check all of the
larger body grips for excessive trigger travel and adjust accordingly.
I hate
to lose an otter when I know I could have prevented it. I don't plan to
lose
any more otters to traps out of adjustment. |