Stanley Hydraulic Tools
Frequently Asked Questions
What are the
torque capacities of the various Stanley Impact Wrenches?
Many applications require a specific bolt torque.
Although an "exact" torque setting is not
possible with Impact Wrenches, the following information
should be useful in determining the Torque Range for the
various Stanley Impact Wrenches.
Since an impact wrench is a rotary hammer (not a steady
torque), bolt torque is affected by several factors such
as thread and thrust face friction, mass of adapters and
sockets, loose connects, and time under impact. Long
shank screws may spring twist and bounce back after
impact, reducing maximum attained torque. Low flow rate
can be used to reduce torque.
For reliable torques, testing GPM flow rate plus
controlling impacting time, followed by a torque wrench
check, can be used to establish repeatable torques for
specific applications.
Model |
GPM Flow |
Lb./Ft. Torque |
||
| 1WO8 | 4-12 |
140-220 |
||
| IW12 | 5-12 |
150-1200 |
||
| IW16 | 7-12 |
500-3000 |
||
| IW24 | 8-12 |
1000-5000 |
||
| IW32 | 10-14 |
6000-9000 |
||
Hydraulic
tools have had a reputation of oil leaks. Comment.
Hydraulic tools got that reputation before the advent of
dripless couplers (a spin off from the space program).
This is not a problem any longer - in fact, air tools
spew out more lubrication oil in mist form than hydraulic
tools leak.
What about
dirt in the hydraulic fluid?
Dirt in any system (air, electric, or hydraulic) will
cause wear. Air tools suffer most from dirt because the
compressor is sucking in dirt all the time and tool
exhaust ports allow dirt to get into the tool. Since the
hydraulic system is a sealed system, dirt gets in only by
carelessness. And, to protect against this, the hydraulic
system has a full-flow filter.
Does hydraulic
fluid have to be changed often?
No. Hydraulic fluid will maintain its operating
characteristics if it's kept cool and clean.
How does the
maintenance cost of hydraulic tools compare with similar
air tools?
Frequency of repair is much lower than with air tools.
Our experience indicates that repair costs for hydraulic
tools are only about half of air tools (analysis of sales
of parts by Stanley Air Tools Division, Cleveland, Ohio,
substantiates this).
Why is this?
In hydraulic tools the parts are bathed in oil and,
generally, have fewer moving parts. Air lines feed dirt
and moisture into air tools which corrode and wear the
tools.
What about
safety if a hose breaks?
If a hydraulic hose should break, someone might get an
oil bath - but that's all (dry cleaning takes it out of
clothes). However, a broken air hose with metal fittings
on the end violently whipping around is very dangerous.
In fact, see the OSHA requirement for attaching air hoses
to tools.
Do hydraulic
tools get too hot to handle?
Not if the hydraulic power system is correctly designed
with an adequate oil cooler. Air tools have a problem in
that they freeze up in cold weather. It's easier to cool
hydraulic tools than heat up air tools (including
dryers).
Double
hydraulic hoses are hard to handle.
There have been improvements in hydraulic hoses over the
years. Hydraulic hoses are available which are lighter in
weight than air hoses. Plumbed hydraulic hose reels are
more convenient and compact than for air hoses.
Hydraulic oil
leakage causes a loss of insulative properties in line
trucks.
Dripless couplers have reduced leakage. The hydraulic
fluid is nonconductive; but surface dirt on the tools and
truck equipment does reduce the insulation effectiveness.
Water in air lines is dangerously conductive and requires
expensive filtering/drying devices.
What size
hydraulic hoses do you recommend for an 8-gpm tool
circuit?
3/8" I.D. - up to 25 feet each way
1/2" I.D. - up; to 50 feet each way
5/8" I.D. - up to 150 feet each way
3/4" I.D. - up to 300 feet each way
Which is less
expensive to run, air tools or hydraulic tools?
Hydraulic tools have an efficiency of 40 - 90% vs. only
10 - 35% for air tools. Air compressors are less
efficient than hydraulic pumps. The lower the efficiency,
the higher the power and fuel cost to operate. An
equivalent hydraulic system can be operated with 1/3 the
power input of an air system.
When filled
with oil, hydraulic tools weigh as much as air tools.
Very little oil fills the hydraulic tools. Talk in terms
of power to weight. When you compare the amount of work
done by each, hydraulics show a much better power to
weight ratio.
How quiet are
hydraulic tools?
The only noise you hear with a hydraulic tool is that of
the work being done. There is no exhaust noise with
hydraulic tools.
In general,
hydraulic tools cost more than air tools; why?
Higher quality and more durable tools just cost more.
However, a hydraulic system actually costs less because
you either eliminate the air compressor cost completely
by using the truck's hydraulic system or use a hydraulic
power unit that costs 1/2 of an air compressor.
What are the
causes of heat in a hydraulic system that should he
minimized in the tool circuit?
In brief, heat occurs any time power is
"wasted". The greatest heat producers are power
supply flow controls, priority valves and relief valves
set too low.
Will an
air-to-oil cooler completely covering the engine radiator
cause overheating of the engine?
No. The recommended coolers are designed for minimum air
resistance and will not restrict air flow to the
radiator. Also, the oil temperature will be lower than
the engine coolant temperature.
At what
pressure should the hydraulic tool be operated?
A tool is designed to operate on a specific flow. The
tool will develop only that pressure required to do the
work. The hydraulic circuit should have the capability to
provide required flow to tools at pressures up to minimum
of 2000 psi relief setting.
What back
pressure can Stanley Hydraulic Tools handle?
Maximum allowable is 250 psi.
Can you run
hydraulic tools from a back-hoe?
Yes. Also from tractors, line trucks, or other vehicles
with hydraulic systems. Consult the factory for your
particular application.
What effect
does OSHA have on the use of hydraulic tools?
In general, the OSHA regulations favor hydraulic tools
over air tools. See section on OSHA and EPA regulations.
In some areas,
air compressors are also used to spray paint, sand blast,
etc. Why not use the air for running all tools?
Look at it the other way, run the air compressor with a
hydraulic motor (Stanley's AC24) so you don't lose the
advantages of hydraulic tools.
What happens
to Stanley hydraulic tools if a customer inadvertently
runs them in reverse?
Our reciprocating tools (breakers, tampers, etc.) will
not operate in reverse and will not be damaged. Impact
wrench operation is not affected since they offer
forward-reverse anyway. Other rotary tools will run in
reverse and will wear the motor seals quickly since the
wrong side of the dynamic seals will be pressurized. Try
to avoid systems that allow reverse oil flow.
What's the
difference between open center and closed center tools?
1) Closed Center: Closed center tools stop system oil
flow entirely when the trigger is released. Oil flow is
totally stopped. The system then senses the pressure
increase and automatically shuts down the pump. When the
tool trigger is pulled the system pressure fails and the
system then activates the pump again. John Deere and
Hi-Ranger utilize closed center systems.
2) Open Center: Open center tools do not stop oil flow.
They either divert oil to the tool mechanism when the
trigger is pulled or they allow the oil to flow back to
the tank when the trigger is released. Oil flow is not
stopped. The great majority of existing hydraulic systems
are open center (including all our power units).
What if I use
an open center tool on a closed center system or
vice-versa?
Closed center tools on open center systems will stop oil
flow entirely when not in use. Full system flow will then
be forced through the system relief valve. No damage; but
some noise and the oil will heat rapidly.
Open center tools on closed center systems will not stop
oil flow and the system will continue to pump oil. No
damage; but the advantages of the c.c. system will be
negated.
What are the
advantages of either an o.c. or a c.c. system?
Open center systems are less complicated than c.c.
systems and are thus less expensive to install. Also,
when a cooler is used an o.c. system continues to pump
oil through the cooler even when the tool is not in use
and thus offers improved cooling.
Closed center systems require an accumulator and a
pressure sensing device in addition to pump, filters,
etc. However,since the system shuts down when the tool
isn't being used there is a potential savings in fuel.
Remember: Probably 90% of existing hydraulic systems are
open center.
What happens
if a customer overspeeds our tools by putting too much
oil through them?
In general all the tools operate noticeably faster and
possible damage can occur.
Our reciprocating tools will not be damaged since they'll
only accept a limited flow until pressure rises above
2000 psi. The excess flow will then be diverted over
system relief back to tank.
The rotary tools will spin faster and impact wrenches
will suffer extremely rapid failure of the impact
mechanism. Wrenches should not be oversped.
Many people think that a tool designed for operation at 8
gpm will work better at 10 or 12 gpm. Not true. Operate
our tools at the suggested gpm's, they'll work right.
One of my
customers has an eight year old bucket truck that has a
circuit capable of 8 gpm at 2000 psi. Our tools don't
work well though. What's wrong with the tools.
Probably nothing is wrong with the tools. They are all
tested before shipment. Most likely, the eight year old
hydraulic system has worn out and isn't providing 8 gpm
any more.
Run the tools from your demo truck to check operation and
test the customer's circuit with our flow and pressure
tester. Remember although the customer always blames the
tools, in many instances it's the circuit thats causing
the problem with high backpressure, low relief settings,
or inadequate gpm's. Check the circuit first!!