MSD 7R SHEARS
Page 16
Section 5
Maintenance
BLADE SHIMMING
Blade rotating is recommended every 80 hours of
shear usage in order to assure uniform wear so
shimming is possible.
After rotating the blades the fi nal time, there is a
possibility there will be a slight gap between the
upper and lower blades, and shimming of the lower
blades may be necessary. A blade gap of 0.005"
to 0.010" (0.13 to 0.25mm) should be maintained
to prevent jamming, especially when cutting light
material.
1.
To check for blade gap, cycle the shear closed so
the secondary blades in the upper and lower start to
bypass. Using a feeler gauge between the upper and
lower blades, check the blade gap and record it.
2.
Cycle the shear closed so the secondary blades
start to bypass at the apex (see fi gure 5-5). Check
the gap at this point using a feeler gauge and record
this measurement also. If the blades have been
rotated properly, and at the right intervals, the gap
in the secondary blades should be fairly even or the
entire span of the blades.
Keep hands away while moving the upper shear.
Do not move upper while checking blade gap
with feeler gauge.
3.
The amount of shims that are installed behind the
blades should be approximately fi ve thousandths
(0.005") (0.13 mm) of an inch less than the
measurements you recorded earlier.
DO NOT
exceed one hundred twenty-fi ve thousandths
(0.125") (3.2 mm), or you may cause structural
damage to the shear, and warranty may be voided.
4.
We recommend keeping the blades with the least
amount of wear in the upper jaw; shim only the
lower blades.
5.
To install the shims, loosen blade bolts and slide
the shim between the blade seat and the blade to be
shimmed and re-tighten the blade bolts.
6.
Use the same procedure for shimming the
primary blade.
7.
Cycle the shear slowly and check that the gap is
not too tight in the throat area, and then recheck
tolerances. Maintain this shimming procedure to
maintain maximum shearing effi ciency and blade
life. However, if the blades are not rotated every 80
hours, shimming may not be possible because of
uneven wear on the blades.
FIGURE 5-5
THROAT AREA
APEX
BLADE SHIM
