Makita HM1202 Technical Information page 6

(Mounting)
(1)Make sure that urethane ring 43 and O ring 38 are
mounted on tool holder in dvance. If not, mount
them on the tool holder.
Insert impact bolt into tool holder, and mount the
tool holder in barrel.
(2)Mount flat washer 37. At this time the side marked with [ UP]
has to be faced upside.
And then, fix the flat washer 37 with ring spring 34.
The side marked with [ UP]
Hammer bit side
O ring 38
Urethane ring 43
UP
Tool holder
Barrel
Tool holder
Flat washer 37
Steel ball 5.6
Ring spring 34
P 6 / 14
Impact bolt
Impact bolt
Crank housing
side
Barrel