Matching Blade Pitch for Both Sets of Blades
Sometimes it may be necessary to match blade pitch between the left and right sets of blades. There are some signs that this may be necessary. For example, the differences in pitch can cause a noticeable difference in finish quality between the left and right sets of blades. The difference in blade pitch can also make the machine difficult to control. This is due to the surface area in contact with the concrete (the blade set with the greater contact area tends to stick to the concrete more).
To synchronize pitch on both sides, the left blade assembly can be pitched by itself. By using the electric blade pitch rocker switches, (Figure 29) the pitch can be syncronized on the left and the right sides.
LEFT 
TWIN
PITCH MORE PITCH PITCH
ONLY LESS PITCH
BLADES TO BE FLAT
WITH FLOAT PANS
Figure 29. Blade Pitch Rocker Switches
Blade Pitch Adjustment Procedure
The maintenance adjustment of blade pitch is an adjustment that is made by a bolt (Figure 30) on the arm of the trowel blade finger.This bolt is the contact point of the trowel arm to the lower wear plate on the thrust collar.The goal of adjustment is to promote consistent blade pitch and finishing quality.
Watch for the following indications when determining if blade pitch adjustments are necessary:
■Is the machine wearing out blades unevenly (i.e. one blade is completely worn out while the others look new)?
■Does the machine have a perceptible rolling or bouncing motion when in use?
■Look at the machine while it is running, do the guard rings “rock up and down” relative to the ground?
STX-SERIES — MAINTENANCE
Adjustments are made by tightening or loosening the blade pitch adjustment bolt (Figure 30).
1.Spider Plate
2.Blade Pitch Adjustment Bolt
3.Trowel Lever
4.Trowel Arm
5.Trowel Blade
Figure 30. Blade Pitch Adjustment Bolt
The easiest and most consistent way to make this adjustment is to use the Trowel Arm Adjustment Fixture (P.N. 9177) that is manufactured by Whiteman Industries. This fixture will allow consistent adjustment of the trowel arm fingers. It comes with all the hardware necessary to properly accomplish this maintenance and instructions on how to properly utilize this tool. Adjusting the trowel arm fingers without a fixture requires a special talent.
If a trowel arm adjustment fixture is not available and immediate adjustment is necessary; we suggest the following procedure. If you can see or feel which blade is pulling harder, adjust the bolt that corresponds to that blade. Another way to determine which blades need adjustment is to place the machine on a flat surface and pitch the blades as flat as possible. Now, look at the adjustment bolts. They should all barely make contact with the lower wear plate on the spider. If you can see that one of them is not making contact; some adjustment will be necessary.
It will be possible to adjust the “high” bolts down to the level of the one that is not touching, or adjust the “low” bolt up to the level of the higher ones. If possible, adjust the low bolt up to the level of the rest of the bolts. This is the fastest way, but may not always work. Verify that after adjustment, the blades pitch correctly. Often times, if the blades are incorrectly adjusted, they will not be able to pitch flat. This occurs when the adjusting bolts have been raised too high. Conversely, sometimes the adjusting bolts are too low and the blades cannot be pitched high enough for finishing operations.
