Operator`s manual

Maintenance section 4 -
© 2010 Alamo Group Inc.
MOWER 04/13
MAINTENANCE SECTION
If so, the shaft should be replaced or straightened. If the vibration is gone - the drive portion of the mower is running smoothly - then
the vibration is probably coming from the cutter shaft (it could be a pulley out of balance or a faulty belt with a varying cross section,
but this is not likely).
The cutter shaft will run out of balance if:
1. Wire, rope, string, rags, etc., around the cutter shaft are holding the knives in a folded back position. Remove such foreign objects
and be sure all knives are free to swing to the extended position.
2. Knives are missing or broken. Replace missing or broken knives.
3. Knife hanger lugs are broken off shaft. This condition usually results from continued operation in contact with large hard objects
where the knife hanger lugs themselves are hitting the hard objects. Lugs should be replaced using arc welding equipment so as
not to direct too much heat in one area of the shaft.
4. Cutter shaft ball bearings are worn enough to have radial “play” in them. Replace ball bearing and other worn parts to eliminate
“play”.
5. Shaft is bent. The shafts are straight within a couple of thousandths of an inch when they are made. It is possible that they will
become bent in use, such as if the shaft is hooked on a stump while the tractor is moving forward at good speed.
6. Shafts are operated at improper speed. Rotating shafts have what is known as a natural period of vibration. The same is true of
the cutter shafts on the Flail Mowers.
The actual speed at which the harmonic will occur will vary with each mower and each installation. To avoid this harmonic vibration
when operating the mower, it may be necessary to adjust the engine speed of the tractor up or down.
Some units have a harmonic which occurs below the nominal operating speed. On these units, it will be noticed that there is always a
little vibration at a particular RPM as the mower is being sped up to operating speed. This occurs as the shaft passes through its normal
harmonic vibration point. As long as the mower is opened at the proper speed, then harmonic vibration will not be an issue.
Proper Torque For Fasteners
The chart lists the correct tightening torque for fasteners. When bolts are to be tightened or replaced, refer to this chart to determine
the grade of bolts and the proper torque except when specic torque values are assigned in manual text.
RECOMMENDED TORQUE IN FOOT POUNDS UNLESS OTHERWISE STATED IN THE MANUAL*
NOTE: These values apply to fasteners as received from supplier, dry or when lubricated with normal engine oil. They do not apply if
special graphited or molydisulphide greases or other extreme pressure lubricants are used. This applies to both UNF ne and UNC
coarse threads.
Proper Torque values for bolts that are measured in inches Proper Torque values for metric bolts
Bolt
diameter
4.8
8.8
10.9
12.9
Head Marking
No Marks
Grade Two
Pound-Foot
Value Dry
4.8
8.8
10.9
12.9
Head M arking
Three Lines
Grade Five
Pound-Foot
Value Dry
4.8
8.8
10.9
12.9
Head Marking
Six Lines
Grade Eight
Pound-Foot
Value Dry
Bolt
diameter
4.8
8.8
10.9
12.9
Head Marking
4.8
Pound-Foot
Value Dry
4.8
8.8
10.9
12.9
Head Marking
8.8 or 9.8
Pound-Foot
Value Dry
4.8
8.8
10.9
12.9
Head Marking
10.9
Pound-Foot
Value Dry
4.8
8.8
10.9
12.9
Head Marking
12.9
Pound-Foot
Value Dry
1/4” 5.5 9 12.6 6mm 4.5 8.5 12 14.5
6/16” 11 18 26 8mm 11 20 30 35
3/8” 20 33 46 10mm 21 40 60 70
7/16” 32 52 76 12mm 37 70 105 120
1/2” 60 80 115 14mm 80 110 165 190
9/18” 70 115 100 18mm 92 175 255 300
6/8” 100 160 225 18mm 125 250 360 410
3/4” 175 280 400 20mm 180 360 600 580
7/8” 175 460 660 22mm 250 475 675 800
1” 270 675 975 24mm 310 600 860 1000
1-1/8” 376 860 1360 27mm 460 875 1260 1600
1-1/4” 630 1200 1960 30mm 625 1200 1700 2000
1-3/8” 700 1550 2550
1-1/2” 930 2100 3350
7