Honda Harmony HRB215SDA Owner's Manual page 59

MAINTENANCE
Blade Installation
1. Clean dirt and grass from around the blade mounting area.
2. Install the blade(s) using the two blade bolts and special washers
as shown.
Be sure to install the special washers with the concave side toward
the blade(s) and the convex side (marked OUT) toward the bolt heads.
The blade bolts and special washers are specially designed for this
application, When replacing bolts or washers, use only genuine
Honda replacement parts.
3. Tighten the blade bolts with a torque wrench. Use a wooden block to
prevent the blade(s) from turning when tightening the bolts.
Blade bolt torque: 36 - 43 ft-lb; 5.0 - 6.0 kg-m (49 - 59 Nom)
If you do not have a torque wrench, have an authorized Honda
servicing dealer tighten the blade bolts before you use the mower.
If the blade bolts are over-tightened, they could break. If the blade
bolts are not tightened enough, they could loosen or come out. In
either case, it would be possible for the blade(s) to fly off while you
are operating the mower.
BLADE(S)
SPECIA
BLAFE(S)
TORQUE WRENCH --