HOWA MACHINERY H3EF, Instruction Manual, Page: 32 / 52

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1. Construction and Operation
1.1 Model Coding
The HIGH SPEED type 3-jaw draw down power chucks are sorted as follows.
H3EF A .
JIS-specified spindle nose No.
No mark
： ： ： ：
Having a straight socket for installation of chuck
(standard model)
： ： ： ：
Including an adapter or a back-plate
Spindle nose No. 5, 6 or 8
Size No. 6 or 8
1.2 Construction and Operation
The HIGH SPEED type 3-jaw draw down chuck
basically consists of a chuck body, draw bars and
draw sleeve.
The draw bars are inserted so as to be at an
angle in relation to the rotational center of the
chuck body. There is a T-form notched groove at
the rear of the draw bar, and the draw bars
engage with the draw sleeve at this notched
groove.
When the draw sleeve is drawn backward, the
draw bars pass through the top jaws with a
wedging operation. The work piece is pulled
toward the chuck edge and gripped.
This chuck cannot grip the inside diameter of the
work piece.
2. Installation
2.1 Unpacking
Take the chuck out of the package box. At this time, be careful not to take out or lift it by hands.
This is because 8-inch chuck weigh over 20 kg, and lifting such a heavy chuck may cause
damage to your lumbar or injury by dropping the chuck. Instead, break open the box and screw
an eyebolt into the screw hole outside the chuck. Then, use a chain block to lift the chuck.
NOTE:
This manual regards the top jaw side as “front” and the draw screw side as “rear”.
Fig. 1
CAUTION
Use the eyebolt when installing or removing the chuck.
(To lift a 6-inch chuck, use a suspender belt. To lift an 8-inch
chuck, use an eyebolt.)
You may drop the chuck or suffer from lumbar injury due to excessive
load.