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DIES (for external threads)
•
To cut an external thread, such as on a bolt, select the correct die for the rod, being threaded, the
die-stock and cutting-oil.
•
The size of the rod or bolt is of great importance. It must not be larger than the desired thread
and preferably .005" to .010" undersized. An oversized workpiece may damage the die and will
make turning very difficult. Slightly undersized workpieces are easier to thread and furnishes
enough thread-height for normal use.
•
After securing the part being threaded, insert the die into the die-stock and run the set screw
snugly into one of the recesses in the outside surface of the die (The recess and slot pattern of
dies allows use with a variety of die stocks)
•
The chamfered side of the die is used for starting the threading operation. Always bevel the end
of the bolt or rod to be threaded, to make angles starting easier. This filed or ground chamfer also
helps in starting at right to the work, which is of major importance.
•
Start the die on the rod with clockwise rotation until it begins leading onto the workpiece. Metal-
chips will flow into the holes provided and should be broken by reversing the direction every 1/4
to 1/2 revolution, depending on the tightness encountered. Continue this operation until threads
of the desired length have been cut. Provide proper lubrication to the workpiece while cutting
threads.
TAPS (for internal threads)
•
To cut an internal thread, select a proper drill-size as per the table shown below, the tap of the
desired size and tap-wrench.
•
The proper hole-size is very important in the formation of good threads. An oversized hole results
in reduced thread-high an undersized hole will overload the tap and will probably cause damage
of the tool or even the workpiece.
•
Select a tap with the required size. Included in the set are for each thread size a taper tap (1
ring), a second tap (2 rings) and a finishing tap (without a ring), which are to be used in that order
for fabricating a thread.
•
Secure the tap by the square in the tap-wrench
•
Fix the workpiece in a bench-vise or by using clamps and start threading by turning the wrench in
clockwise direction. Great care must be taken to start the tap square to the hole. As the tap is
turned it bites into the metal and leads into the hole.
•
After the tap has been started, the metal-chips that flow into the flute spaces must be broken to
relieve pressure on the tap. This is accomplished by reversing the tap-direction every 1/4 to 1/2
revolution depending on the tightness encountered. Providing lubrication to the cutting edges
while tapping will result in smoother threads and longer tap-life.
•
Continue threading until the tap passes through the workpiece or it reaches the bottom of the
hole.
•
When tapping a blind hole (one that does not pass entirely through the workpiece) take care in
drilling to provide clearance at the bottom for metal-chips and the starter-threads. These
chamfered threads on the end of the tap will not cut full threads.
TABLE FOR DRILL HOLE (tap)
Nominal (mm)
M3
M4
M5
M6
M7
M8
M9
M10
M11
M12
BGS technic KG
Bandwirkerstr. 3
D-42929 Wermelskirchen
Metric Normal
Pitch (mm)
Drill Ø (mm)
0.5
2.4
0.7
3.2
0.8
4.1
1.0
4.9
1,0
6,0
1.25
6.6
1,25
7,8
1.5
8.4
1,5
9,5
1.75
10.1
Tel.: 02196 720480
Fax.: 02196 7204820
mail@bgs-technic.de
.
Metric Fine
Nominal (mm)
Pitch (mm)
M3
0.35
M4
0.5
M5
0.5
M6
0.75
M7
0,75
M8
1.0
M9
0,75
M10
1.25
M11
0,75
M12
1.5
www.bgstechnic.com
© BGS technic KG, Copying and further use not allowed
Drill Ø (mm)
2.6
3.5
4.5
5.2
6,2
6.9
8,2
8.6
10,2
10.4
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