Checking The Wear Of The Driver Chuck And Cylinder; Shimming; Assembly Of The Drill Bit And Driver Chuck; Wear Limits - Atlas Copco SECOROC COP 34 Manual

to the drill bit after grinding
or replacing a drill bit, its
radial location on the bit
shank should be advanced
by one spline section. This
will give a more even dis-
tribution of wear on the
driver chuck and hammer
cylinder.
If the driver chuck is
exposed to exceptionnally
heavy wear, e.g. when
drilling in rock formations
with a high quartz content (granite, quartzite etc.), it may be necessary
to turn the driver chuck by more than one spline section in order to
prevent the driver chuck and hammer cylinder from wearing out too
quickly. As a rule, the cuttings grooves in the bit should always be
pointing towards the part of the driver chuck that is least worn.
Since the hammer cylinder has three thread inlets, the part of the
driver chuck that is worn the most can be located against the part of
the hammer that is worn the least.
Checking the wear of the driver chuck and
hammer cylinder
Wear to the driver chuck and hammer cylinder should be checked
regularly, e.g. every time the bit is reground or changed. Measure
the diameter of the hammer cylinder using a sliding calliper. Measure
along the full length of the cylinder, with the exception of the outermost
100 mm at each end. At any point between these points, the diameter
of the hammer cylinder must not be less than the mini mum permis-
sible diameter given for the respective DTH hammer sizes in the table
below.
Minimum permissible diameter
COP 34 78 mm
COP 44 89 mm
COP 54 111 mm
COP 64.2 132 mm
COP 64.3 130 mm
COP 84.2L 148 mm
COP 84 164 mm
The outside diameter of the driver chuck must not be less than that
of the hammer cylinder.
N.B. When the hammer cylinder has to be changed, the driver chuck
must be replaced at the same time (see the section "Wear limits").
The hammer should be overhauled at suitable inter vals, depending
on the operating con ditions. The abrasiveness of the rock will affect
the overhauling intervals, since it has a strong bearing on the rate
of wear.

Shimming

Checking the clearance between
the top sub and the cylinder
N.B. Not applicable on COP 64.2, COP 64.3
and COP 84.2L.
When fi tting the top sub to the hammer,
the clearance between the top sub and the
cylinder must be checked with a feeler gauge. This is done as follows:
Remove the valve body D and compression ring B from the cylin-
der.
Remove the control tube G and buffer housing H from the cylinder,
using a rod.
Remove the outer buffer K from the control tube, (the inner buffer
J should not be removed).
Smear the O-ring on buffer housing H and the inner buffer J with
silicone grease. Oil all other surfaces of the control tube G with oil.
Fit the buffer housing H and control tube G back into cylinder.
Fit the compression ring B and valve body D back into the cylinder.
A B C
10
D E F
Remove the O-ring E from the top sub F.
Thread the top sub into the cylinder and tighten it by hand.
Clearance before/after shimming
Ordering No.
shims (1–4)
COP 34 3161-1322-00
COP 44 3161-1422-00
COP 54 3161-1522-00
COP 84 3161-1822-00
Measure the clearance between the top sub and cylinder.
If the clearance is less than the minimum value given in the table,
shimming must be carried out.
Fit the necessary number of shims C (1 – 4 pcs) between the com-
pression ring B and valve body D.
If, after the maximum number of shims (4 pcs) has been inserted, the
minimum clearance is still less than the value shown in the table, then
the compression ring or circlip is worn out and must be replaced.
After inspection and eventual shimming, smear the outer rubber
buffer K with silicone grease and fi t it back into the cylinder together
with the control tube G and buffer housing H.
Then fi t all other parts back into cylinder.
N.B. Do not forget O-ring E — fi rst smear it with silicone grease and
then fi t it back on to the top sub.
Finally, smear the threads of the top sub with Atlas Copco thread
grease, and thread it into the cylinder. Tighten hard with the aid of a
wrench. There should now be hardly any clearance between the top
sub and cylinder.
Buffer rings (J, K) for COP 34/64.2/64.3/84.2L/84
IMPORTANT!
The buffer rings must be
mounted with their concave
(curved) sur faces towards the
control tube fl ange. Incor-
rectly fi tted buffer rings can
cause serious damage to the
hammer.

Assembly of the drill bit and driver chuck

Smear the splines of the bit shank with Atlas Copco thread
grease.
Smear the O-ring of the stop
ring with silicone grease.
Assemble the bit 1, driver
chuck 2 and stop ring 3 as shown
in fi gure.
IMPORTANT!
Make sure the stop ring is located
correctly, and that it faces the
right direction. Incorrect fi tting
will result in severe damage to
the hammer.
Smear the thread on the driver chuck with
Atlas Copco thread grease.
Screw in the bit assembly by hand. Note that there should be a
clearance of 0.1–0.4 mm between the driver chuck and the cylinder
casing. If there is no clearance, the end surface of the cylinder casing
should be ground down as necessary. Tighten the driver chuck with
the aid of the bit spanner.
G J
H K
Min. Clearance
clearance after shimming
1,3 mm 1,7 – 2,3 mm
1,5 mm 1,9 – 2,5 mm
1,8 mm 2,2 – 3,0 mm
2,5 mm 3,0 – 4,0 mm
J K