Originally Posted By: The_Eric
Why do you say that?
Originally Posted By: Trav
The way i understand it is for automotive type work twin hammer is preferable unless you like shearing smaller bolts.
Its like hitting a wrench a few thousand times a minute with a hammer, it works on smaller and larger bolts equally well.
On their lowest setting torque is very low and can be further reduced by a variable trigger.
Clutch types are more for industrial use and mostly large nuts and bolts.
These produce a lot of torque right out of the gate, even on the lowest setting it can be considerable.
The force of the impacts is much lighter than a twin hammer, these rely more on torque.
You find most cordless impacts like the IR W7150 use a pin clutch mechanism it goes a long way in compensating for the weaker battery powered motors.
When connected to a powerful air motor they become bold shearing monsters, not what you want to remove rusted exhaust manifold to pipe nuts, you want to hammer them loose.
I have tried pin clutch guns over the years and don't like them, they hindered more than helped a lot of the time by just breaking the head or stud off. You cant beat a good twin hammer for automotive work.
AIRCAT® 1150 model impact wrench uses a Durable Twin Hammer Mechanism.
The Rugged and Reliable Twin Hammer mechanism creates a higher speed and faster blow per minute (under a load) impact. The Twin Hammer is best suited for all-around automotive maintenance. The twin hammer design has the hammer able to slide and rotate on a shaft, with a spring holding it in the downwards position. Between the hammer and the driving shaft is a steel ball on a ramp, such that if the input shaft rotates ahead of the hammer with enough torque, the spring is compressed and the hammer is slid backwards. On the bottom of the hammer, and the top of the anvil, are dog teeth, designed for high impacts. When the tool is used, the hammer rotates until its dog teeth contact the teeth on the anvil, stopping the hammer from rotating. The input shaft continues to turn, causing the ramp to lift the steel ball, lifting the hammer assembly until the dog teeth no longer engage the anvil, and the hammer is free to spin again. The hammer then springs forward to the bottom of the ball ramp, and is accelerated by the input shaft, until the dog teeth contact the anvil again, delivering the impact
Faster hard hitting impact (1,400 Blows Per Minute)
Durable, Rugged and Reliable
Recommended for all-around automotive torque applications
NITROCAT 1200-K model impact wrench use a Smooth Powerful Twin Clutch Mechanism
The Hard Hitting Twin Clutch mechanism creates a high torque initial impact.
The Twin Clutch design uses a hammer fixed directly onto the input shaft, with a pair of pins acting as clutches. When the hammer rotates past the anvil, a ball ramp pushes the pins outwards against a spring, extending them to where they will hit the anvil and deliver the impact, then release and spring back into the hammer, usually by having the balls "fall off" the other side of the ramp at the instant the hammer hits. Since the ramp need only have one peak around the shaft, and the engagement of the hammer with the anvil is not based on a number of teeth between them, this design allows the hammer to accelerate for a full revolution before contacting the anvil, giving it more time to accelerate and delivering a stronger impact.
“An 800 lb Gorilla”
Slower but harder hitting impact
Recommended for high torque applications