Not necessarily when to change; but when to sharpen mower blades: The easiest way to know is by observing the way the grass is cut. A sharp blade will make a "clean cut" on the grass blades, whereas a dull blade will "tear" the grass and leave a "ragged" appearance. As far as when to change out the blades, there is no set time interval, you just have to visually evaluate the condition of the blade (bent, badly worn, warped, etc.) to determine when to change. If your mower uses 2 blades, it would be wise to change both blades at the same time.
Scalping in turf grass is caused by :- (a) Setting the height of cut too low and removing too much of the grass blades as you cut. This can leave the the lawn looking straw coloured as if it had been scorched. (b) Removing most, or all of the grass blades on raised areas of the lawn as you mow over them even if the height of cut is correctly set for the majority of the area.
This is a very general answer to your question. A variable pitch propeller can be turned . If the blades were flat faceing forward they would not do their job. When the blades are turned at a slight angle (the pitch) then they bite into the air and this helps with forward movement. The more pitch the better the blades cut into the air, but if the pitch is to much, then the blades no longer cut into the air and forward motion stops. The blades can be set for reverse pitch which allows a plane to slow down very quickly once it has landed on a runway (this helps to save on the brakes) and can also be used to back a plane up, such as from a boarding gate, or to park a plane.
Your blades either need to be replaced or sharpened quite a bit. Either that or your cutter is set too high and needs to be lowered.
I have cut and drilled many plastics and have not found a dedicated set for that. I use regular drill bits and blades and reduce the speed, so as not to melt or burn the plastic
Beck's Blades and Repair sharpens clipper blade sets for 5.00 (small) and 6.00 (large).
Helicopters have 2 sets of blades to keep the helicopter balanced. This is due to the unique shape of the helicopter.
A set of steam-powered fan blades that spins a generator at a power plant is called a turbine. The steam produced by boiling water is used to drive the turbine blades, converting the thermal energy into mechanical energy to rotate the generator and produce electricity.
Xemnas' ethereal blades are his main weapons. They are two blades of energy that extend directly from his hands. They can be extended or shortened at will, as well as shot like projectiles. Interdiction is the best set of ethereal blades that Xemnas can use in Mission Mode of Kingdom Hearts 358/2 Days.
Yes, you sharpen both blades. Professional blade sharpeners refer to the set as a "clipper blade".
No, you cannot visibly see the speakers. The speakers are set internally in the hardware of the iPod.
In an impulse turbine, the stage is a set of moving blades behind the nozzle. In a reaction turbine, each row of blades is called a "stage." A single Curtis stage may consist of two or more rows of moving blades.