Mincon HDD40 Operation manual

Copyright © Mincon 2010, All Rights Reserved.
HDD40
Operation and Service Manual

Mincon – “Leaders in Rock Drilling Technology” Page 2
TABLE OF CONTENTS
Table of Contents..........................................................................................2
1Introduction...............................................................................................3
2Installation and Operation.........................................................................4
2.1 Safety.......................................................................................................................................4
2.2 Set up of HDD40 Hammer and Sonde.....................................................................................4
2.2.1 Storage .......................................................................................................................................................... 4
2.2.2 Setup of Sonde..............................................................................................................................................4
2.2.2.1 Installation of DCI Sonde..................................................................................................................................................4
2.2.2.2 Installation of Sub-Sight Sonde........................................................................................................................................8
2.2.3 Installation of Bit............................................................................................................................................. 9
2.3 Setup and Operation of Support Station................................................................................10
2.3.1 Set up of Support Station.............................................................................................................................11
2.3.2 Equipment Inspection Prior to Compressor Ignition....................................................................................13
2.3.3 Pressure Regulator Adjustment...................................................................................................................14
2.3.4 Oiler Adjustment .......................................................................................................................................... 14
2.3.5 Water Pump Adjustment and Operation......................................................................................................14
2.3.6 Commissioning of Hammer ......................................................................................................................... 15
2.3.7 Lubrication ...................................................................................................................................................15
2.3.8 Operation of Hammer ..................................................................................................................................15
2.4 Servicing................................................................................................................................17
2.4.1 General ........................................................................................................................................................ 17
2.4.2 Opening Chuck and Backhead....................................................................................................................17
2.4.3 Dismantling Hammer to Change Drill Bit.....................................................................................................18
2.4.4 Disassembly for Full Servicing of Hammer..................................................................................................18
2.4.5 Inspection.....................................................................................................................................................18
2.4.6 Checking Wear Limits..................................................................................................................................18
2.4.7 Reassembly.................................................................................................................................................18
3Appendix.................................................................................................20
3.1 HDD40 exploded view and Parts List.....................................................................................20
3.2 HDD40 Hammer Service Log ................................................................................................21
4Warranty .................................................................................................22

Mincon – “Leaders in Rock Drilling Technology” Page 3
1 Introduction
This document covers the HDD40 Horizontal Directional Drilling System. The system connected to the drill using the following:
•HDD40 Horizontal Directional Hammer
•Support Station
•Compressor
•Water supply
The basic setup is shown below.
The Installation and Operation section will deal with setup of the system and basic operation. Following that we will deal with
disassembly and servicing. When dealing with the HDD40 in the service section we will separate it into two parts: Firstly the Horizontal
Directional Drilling hammer component that makes drilling possible and secondly the Sonde housing component that makes steering
possible.
Water Tank
Dust Control
Sonde Cooling
2-4 Gal/Min
Compressor
Minimum 275 PSI Support Station
Rock Drill Oil Injection
Water injection
Compressor to Drill adapter
Horizontal Directional Drill
Including but not limited to:
Astec 3238, DD4045, DD 4
Ditch Witch 2720 M1, JT3020, JT4020 M1
Vermeer 24X40, 36X50, 50X100

Mincon – “Leaders in Rock Drilling Technology” Page 4
2 Installation and Operation
2.1 Safety
Be sure to work safely at all times. Wear protective clothing and safety equipment and observe all safety regulations as prescribed by
your employer, Government, or the site on which you work. Do not wear loose clothing that may get caught in rotating parts and cause
serious personal injury. Remember that a “Horizontal Down-the-Hole” percussive hammer emits noise and you should therefore take
every precaution to safeguard your hearing against damage by using proper ear protectors.
Use eye protection at all times. Rock chips and dust which may be discharged from the face of the bit or bore hole at high velocities
and can cause severe injury. Hammers can be heavy – Always use proper and approved lifting equipment and take every precaution
to safeguard yourself against injury. Keep hands clear at all times – Beware of getting fingers trapped between the chuck and bit and
do not use hands or feet to clear the top of the borehole at any time. Other safety advice is given throughout this document which you
are advised to read.
2.2 Set up of HDD40 Hammer and Sonde
2.2.1 Storage
If you intend to store the HDD40 Hammer we recommend that ½ pint (¼ litre) of good quality rock drill oil be poured into the hammer to
protect it. To do this the hammer section should be unscrewed from the Bent Sub and then the oil should be poured into the top of the
hammer and let flow down into the piston chamber of the hammer to coat the parts and protect them from rust and corrosion. Once
completed the bent sub and the Sonde Housing can be reinstalled. Ensure that the thread protector and chuck cap are fitted to keep
debris out and to prevent oil leakage. Store the hammer horizontally in a clean dry place.
2.2.2 Setup of Sonde
When the HDD40 is supplied it will contain the necessary parts for the successful installation of a commercial Sonde. The two main
types of Sonde are dealt with in this manual: DCI Sonde and Sub Sight.
2.2.2.1 Installation of DCI Sonde
The following series of picture will detail the installation of a DCI Sonde into the HDD40. The same procedure should be used for
servicing or changing the Sonde at a later date.
STEP1 STEP2
Unscrew and remove Sonde Housing Backhead from the
Sonde Housing Sleeve Insert and screw the Sonde Line Up Tool into the Sonde Carriage retrieval cap and pull out the complete Sonde
Carriage assembly.

Mincon – “Leaders in Rock Drilling Technology” Page 5
Step3 Step4
Unscrew and remove the Sonde Carriage Locating Cap,
Springs and the DCI Adapter from the Sonde Carriage (At
Opposite end to the Sonde Carriage retrieval cap)
Loosen and remove with the Torque Wrench the DCI Adaptor
Locating cap from the tube. The correct end has locating
dimple.
Step5 Step6
Insert and push the DCI Sonde into the tube. Fit the DCI Adaptor Locating cap onto the DCI Sonde
ensuring the Locating cap’s intrical key is seated correctly in
the Sonde Keyway.

Mincon – “Leaders in Rock Drilling Technology” Page 6
Step7 Step8 Step9 Step10
Push the Sonde in the rest of the way
and screw the DCI Adaptor Locating
Cap in and tighten snugly with the
Torque wrench.
Insert first spring into the
Sonde Carriage. Insert the DCI Adaptor into the Sonde Carriage Insert the second spring in to the Sonde Carriage.
Step11 Step12 Step13
Align the Sonde Carriage Locating Cap
Groove with the DCI Adaptor Locking Dimple
and push the cap on so that the hex socket
of the Carriage Locating Cap fits over the
DCI Adaptor and then screw the Carriage
Locking Cap in place
Push the Sonde carriage into the Sonde
Housing Sleeve with the Sonde Carriage
Locating cap entering first.
Screw the Retrieval bar into the Sonde
Carriage and push forward until it stops.
Turn gently until you feel the Sonde
Carriage go forward and the Sonde
Carriage Locking Cap groove seats
over the Sonde Carriage Locating pin
(See Step 14 for details of the pin).
DCI Adaptor
Locating
Dimple
Sonde Carriage
Locating Cap
Groove

Mincon – “Leaders in Rock Drilling Technology” Page 7
Step14 Step15
Above picture shows the Sonde Carriage Locating Pin. The pin is in the
Bent Sub set so that the Sonde will be aligned correctly in the twelve
O’clock position.
Insert and screw the Sonde Housing Backhead in place.
Sonde Carriage
Locating Pin

Mincon – “Leaders in Rock Drilling Technology” Page 8
2.2.2.2 Installation of Sub-Sight Sonde
The procedure for installing a Sub-Sight Sonde is the same as the DCI Sonde except Step 3 through Step 7 are replaced with the
following:
Step1 Step2 Step3
Above picture shows the end of the Sub
Sight Sonde that will receive the Sub Sight
Locating adaptor.
All screws to be inserted should have
the threads coated with a thread lock
compound.
Fit the first half of the Sub Sight adaptor to
the Sonde and tighten.
Step4 Step5 Step6
Fit the second half of the Sub Sight
adaptor to the Sonde and tighten. Then fit
the assembly locking screw as shown
above.
Fit the top section of the Sub Sight
locating assembly and tighten. Unscrew the other end off the Subsight and replace with the Adaptor end cap shown
above. Once completed the Sonde
assembly can be installed from Step 8
above.

Mincon – “Leaders in Rock Drilling Technology” Page 9
2.2.3 Installation of Bit
The following sequence of instructions is used to correctly fit the bit in the correct orientation for drilling.
Step1 Step2
Unscrew and remove the Chuck from the Hammer. Remove Bit Retaining Ring from the Chuck and screw the
Chuck back in place.
Step3
Insert the bit into the Chuck so that the Bent Sub wear carbides are aligned in a straight line with the three bit wear carbides as
illustrated above.

Mincon – “Leaders in Rock Drilling Technology” Page 10
Step4 Step5
Unscrew the Chuck and Bit from the hammer making sure that
the bit does not come out of the Chuck. Insert the Bit Retaining Rings back into the Chuck as shown above making sure that the Bit does not come out of the
Chuck.
Step6
Push the Chuck forward to secure the Bit Retaining Ring in place against the rear splines. Screw the Chuck, Bit and Bit
Retaining Rings in place.
2.3 Setup and Operation of Support Station
Prior to operation the Support Station must be setup to ensure that correct and safe operation of the equipment is carried out.
CAUTION – For safe working conditions during operation of the equipment it is essential to have received the appropriate training prior
to starting up the equipment.

Mincon – “Leaders in Rock Drilling Technology” Page 11
2.3.1 Set up of Support Station
Step1
Unpack Support Station and check to make sure all components are present.
Step2 Step3 Step4
Support Station comes delivered with whip
checks in place on both the air intake and
discharge lines. Enlarge loop on the other
end of the whip check on the air intake valve
end and loop over air hose and release.
Connect air hose to Support Station air
intake valve. When completed pull whip checks back so that they are as shown
above. Above picture shows air
discharge side of support station.
Support Station
20’ Air Hose
30’ Air Hose
Water Hose
TRI-Lite
Valve
Controller
Whip Checks
2” NPT Couplings

Mincon – “Leaders in Rock Drilling Technology” Page 12
Step5 Step6 Step7
Connect air hose to the compressor in the
same manner. Connect other air hose to
Support Station discharge line and to Drill
also using the same procedure.
Hook TRI light controller
connections to electric valve Before Operation, check level of oil in the water pump fill cap with dip stick.
Step8
CAUTION: Always follow these instructions when filling tank with rock drill oil.
1. Turn compressor off and shut valve off at compressor.
2. Turn electric valve off make sure you see a red light on the Tri-Lite Controller and Red or Yellow indicator on the top of valve
is pointing perpendicular to valve body.
3. Open vent valve (Labelled #1 Vent Valve above) lower right hand control knob, relieving air pressure inside of tank to
atmospheric air pressure.
4. After air has bled out of tank, use hammer to hit four inch hammer fitting on top of tank counter clockwise to loosen, and then
take off by hand.
5. Fill oil to top of tank, but not past fitting in the middle of the neck.
6. Refit Oil tank cap and tighten using a hammer.
CAUTION: Always make sure 4” cap is tight on tank and vent valve is closed before starting compressor.

Mincon – “Leaders in Rock Drilling Technology” Page 13
2.3.2 Equipment Inspection Prior to Compressor Ignition
CAUTION: The following walk around check should be carried out prior to starting the compressor.
Step Specific Equipment Required State Complaint
()
1 Hose connecting Drill to Support Station RED Air flow arrow goes to Drill. Hose connected
to outlet valve.
2 Hose connecting compressor to Support Station Connected at electric inlet valve.
3 Inlet and Outlet Valve Connections Wing nuts tightened using hammer turning
clockwise.
4 Inlet and outlet valves on Support Station Whip
Checks Connected correctly as described in above sections.
5 Hose to compressor connection Wing nuts tightened using hammer turning
clockwise.
6 Hose to compressor connection Whip Check Connected correctly as described in above
sections.
7 Hose to Drill connection Wing nuts tightened using hammer turning
clockwise.
8 Hose to Drill connection Whip Check Connected correctly as described in above
sections.
9 4” Wing Nut on top of Rock Drill Oil Tank Tightened using hammer turning clockwise.
10 Rock Drill Oil Tank Vent Valve Closed (knob pointing to
up as in Photo)
11 Main Air Discharge valve (2” Valve to Drill) Open (Parallel to Valve Body)
12 Power Connections for Tri-Lite Controller Connected to 12V Battery – Black to NEGATIVE
(-) and Red to POSITIVE (+)
13 Tri-Lite Controller Valve Operation Operating correctly – Red light means air off
(Valve closed) Green light air on (Valve Open)
14 Tri-Lite Controller Valve Red light – air off (Valve closed) prior to starting
compressor

Mincon – “Leaders in Rock Drilling Technology” Page 14
2.3.3 Pressure Regulator Adjustment
On a new support station, the pressure regulator needs to be set at
80 PSI. To adjust the pressure after the walk around inspection and
the compressor is operational, turn the Air Discharge Valve (Valve to
Drill - 2” ball valve) off, Turn electric valve on (green light on) this will
pressurize the system.
Adjust the regulator clockwise to turn air pressure up and counter
clockwise to turn pressure down. Set pressure gauge to 80 PSI.
After adjustment turn electric valve off (red light) and turn Air
Discharge Valve on, handle parallel to the valve body.
CAUTION; Operating at higher pressures may cause motor to
develop an air lock and stop operating.
2.3.4 Oiler Adjustment
The amount of oil is dependent on where the needle valve is set. The
needle valve is located on the far left as shown here. Turning the valve
counter clockwise provides more oil and clockwise gives less oil. A good
starting point is to close the valve fully and then turn one and a half
revolutions to the counter clockwise. The two valves located on the control
panel (see photo) are how you turn the oiler on and off. During drilling the
two valves should be ON. When not drilling turn valves OFF.
CAUTION: At the end of the day turn the valves off or you will be wasting
oil. The oiler will continue to oil whether compressor is on or off. It is
recommended that on a new system, until the operator is familiar with the
system that after each rod is drilled down ¼ cup or two ounces of rock drill
oil be poured in each rod, especially if a new hammer is being
commissioned.
2.3.5 Water Pump Adjustment and Operation
Always prime water hose before hooking the cam lock to the pump. It is essential to have the water tank above the support station to
maintain sufficient head pressure for the pump to operate.
The amount of water being introduced into the drilling operation
is controlled by turning the knob labelled water on front panel to
desired amount of flow. The amount of water required to
maintain a clean hole will be dependent on the drilling
conditions. Approximately 3-4 gallons per minute will suffice
however in softer rock conditions more water may be required
and significantly harder conditions will require less. Once the
optimal water injection is set the water will turn off when the
operator turns off the main air supply to the drill and conversely
turn on when the main air supply is turned on. It is best to adjust
the water while drilling as conditions can change throughout the
bore hole.
CAUTION: Never turn the water pump on with the main discharge valve (2” Ball valve to Drill) on the support station closed. The
water should always have a path out and through the drill string. Always use clean water. Bentonite should not be used as this will clog
up the hammer requiring a complete overhaul to return the hammer to an operable condition. A good mixture of polymer and Condet is
acceptable if drilling in clay. Check the in-line filter on the pump periodically for debris.In colder conditions antifreeze the pump and
drain the 40 foot water hose and clean and empty the in-line filter to protect from freezing while not operating the drill.

Mincon – “Leaders in Rock Drilling Technology” Page 15
2.3.6 Commissioning of Hammer
Coat the drill bit shank and the hammer threads with grease for protection and easier dismantling. Prior to use, lubricate the hammer
with ½ pint (¼ litre) of rock drill oil as described above.
Fit the hammer to the drilling rig ensuring no debris or dirt enters the hammer from the site, dirty tubes or from unclean air lines. Make
sure that the coupling threads from the drill are of the same specification to that of the hammer and they are in good condition.
Run the hammer at half the air flow for a few minutes to allow the oil to flow through and for internal components to settle in.
2.3.7 Lubrication
It is vital for HDD hammers to receive a constant supply of proper rock drill oil to protect the internal components and to provide a good
air seal between the piston and the inner cylinder, and the piston and the wear sleeve for efficient drilling. The correct consumption of
oil is dependent upon the air volume and conditions. Please refer to the lubrication graph below for recommendations. When drilling in
wet conditions the normal amount should be doubled. There should be visual evidence of oil around the drill bit shank and within the
tube joints when changing tubes.
The recommended grade of oil is dependent on the ambient temperature in which drilling is taking place as well as the operating
pressure. As a rule of thumb, ISO320 grade rock drill oil should be used whenever possible as the hammer is a high frequency tool,
however, where the pump cannot pump the oil in colder conditions, a lower grade of oil can be used as per the graph above.
Remember: Insufficient lubrication or incorrect lubrication grades may result in damage being caused to the hammer and its
components. Hydraulic oils, engine oils, gear oils and diesel are not recommended for lubricating HDD hammers.
2.3.8 Operation of Hammer
Be sure to familiarize yourself with the controls of the machine and work in accordance with the manufacturers recommendations.
The percussive mechanism begins to operate as the air supply is turned on and when the drill bit is pushed firmly into the hammer.
Excessive thrust pressures are not needed to make it work. The thrust controls on the drill should be adjusted to the correct pressure
and should be readjusted to take account of the weight of any extra tubes added so that the thrust pressure remains constant and not
excessive. Insufficient thrust pressure will make the hammer drill erratically and less efficiently and cause premature wear to the bit
and chuck splines with likely damage to the hammer components and threads.
2
4
250
500
750
1000
1250
1
3
5
1500
7.0
14.0
21.0
28.0
35.0
42.0
1
2.0
0.5 1.5
2.5
US Pints/Hour
Litres/Hour
Air Volume - CFM
Air Volume – M
3
/MIN
In wet drilling (above 2gpm/8 lpm) the oil
consumption should be doubled
Pressure - PSI
Pressure - Bar
Ambient Temperature ºF
Ambient Temperature ºC
200
400
0
20
40
60
80
100
300
500
100
-17.8
-6.7
4.4
15.6
26.7
37.8
13.8
27.6
6.9
20.7
34.5
120
48.9
-20 -28.9
ISO46
ISO150
ISO320

Mincon – “Leaders in Rock Drilling Technology” Page 16
When the hammer is lifted from the rock face, the drill bit extends from the chuck and the percussive action ceases. Extra air will pass
through the hammer, which can be used to flush the hole clean.
Rotation speeds should not be too high and should be selected to suit drilling conditions and drill bit diameters. High rotation speeds do
not provide fast drilling and can cause premature wear of drill bits, hammers and tubes. Too slow a rotation speed can cause binding in
the borehole and damage to drill bit inserts.
The controls of the drill should be adjusted in order to provide the largest drill chip size with the smoothest rotation and feed
characteristics. Recommended rotation speeds would normally vary between 25 – 35 R.P.M. for most applications.
Where big diameter drill bits are used or when drilling in hard abrasive rocks, slower rotation speeds are recommended. Conversely, in
soft, non-abrasive rock a slightly faster rotation speed may be selected to produce more satisfactory results.
Some ground conditions may cause binding within the hole, with the added risk of the hammer and drill string becoming jammed. Any
excessive pullback forces or high rotation speeds used in an attempt to recover the drill string may generate heat zones around the
hammer, which may alter the metallurgy of the components to cause damage and ultimate failure.
You are strongly advised not
to pour diesel into the hammer as this may create an internal combustive effect and will damage the
hammer and its components. Any heat induced failures are not covered by our terms of warranty.
Before adding a drill rod make sure that the threads are clean and well greased and that there are no contaminants likely to enter the
hammer to cause damage and early wear.
Proper drill guides and break out systems must be used which suit the diameter of the hammer. All tools and spanners used for the drill
bit and break out flats must fit properly.
Make certain that the hammer is stationary when applying spanner or breakout tools. Do not rotate the hammer with a spanner
attached to the drill string unless it is safely captivated within the breakout clamp.
The Air Consumption of the hammer is as per the chart below. The chart represents operating pressure and equivalent air
consumption at sea level with an ambient temperature of 68°F (20°C).

Mincon – “Leaders in Rock Drilling Technology” Page 17
Both temperature and altitude have an effect on air and consequently on compressed air. Higher temperatures and higher altitudes
result in air becoming thinner, less dense, and the effect of this is a reduction in a compressor’s delivery pressure.
The table below shows just how much operating pressure can be affected by these two factors. For example, if we take a compressor
which will deliver 1000 cfm at sea level, this same compressor will only deliver 745 cfm at 9,000ft, given a temperature of 40 degrees
Fahrenheit (4.4 degrees Celsius).
°F °C Sea Level 1000ft 3000ft 5000ft 7000ft 9000ft 11000ft 13000ft 15000ft
Sea Level 305m 915m 1524m 2134m 2744m 3354m 3963m 4573m
-40 -40 0.805 0.835 0.898 0.968 1.043 1.127 1.217 1.317 1.426
-30 -34.4 0.824 0.855 0.920 0.991 1.068 1.154 1.246 1.349 1.460
-20 -28.9 0.844 0.875 0.941 1.014 1.092 1.180 1.275 1.380 1.494
-10 -23.3 0.863 0.895 0.962 1.037 1.117 1.207 1.304 1.411 1.528
0 -17.8 0.882 0.915 0.984 1.060 1.142 1.234 1.333 1.443 1.562
10 -12.2 0.901 0.935 1.005 1.083 1.167 1.261 1.362 1.474 1.596
20 -6.7 0.920 0.954 1.026 1.106 1.192 1.288 1.391 1.506 1.630
30 -1.1 0.939 0.974 1.048 1.129 1.217 1.315 1.420 1.537 1.664
40 4.4 0.959 0.994 1.069 1.152 1.241 1.341 1.449 1.568 1.698
50 10 0.978 1.014 1.091 1.175 1.266 1.368 1.478 1.600 1.732
60 15.6 0.997 1.034 1.112 1.198 1.291 1.395 1.507 1.631 1.766
70 21.1 1.016 1.054 1.133 1.221 1.316 1.422 1.536 1.662 1.800
80 26.7 1.035 1.074 1.155 1.244 1.341 1.449 1.565 1.694 1.834
90 32.2 1.055 1.094 1.176 1.267 1.365 1.475 1.594 1.725 1.868
100 37.8 1.074 1.114 1.198 1.290 1.390 1.502 1.623 1.756 1.902
110 43.3 1.093 1.133 1.219 1.313 1.415 1.529 1.652 1.783 1.936
120 48.9 1.112 1.153 1.240 1.336 1.440 1.556 1.681 1.819 1.970
2.4 Servicing
2.4.1 General
Dismantling the Hammer for servicing or to change the bit can be made easier if the chuck threads are regularly greased and the
backhead threads are well greased any time the hammer is opened for servicing. We recommend that a good quality thread grease be
used, and in acidic conditions, we do not recommend copper based greases as this can trigger a galvanic reaction with corrosive effect
to damage the root of the threads and cause failure.
2.4.2 Opening Chuck and Backhead
The threads used in Mincon Hammers are right hand threads. Proper tools and break-out systems should be used at all times to
dismantle HDD hammers, otherwise damage may be caused to the components which could result in eventual failure or affect the
performance of the Hammer. When using Petol wrenches or similar systems, ensure that the wrench is not placed on the threaded
section of the wear sleeve. Petol wrench jaws should be carbide, and in good condition. It is good practice to keep a spare set of jaws
with the rig. Do not strike or hit the outer components as this could weaken the heat treated steels. Hitting the hammer may also cause
hard metal fragments to be chipped off which may be projected and cause personal injury or eyesight loss.
Do not apply heat to the hammer, as this can alter the metallurgical composition and result in premature failure. Additionally, applying
heat can also cause distortion to the wear sleeve, which in turn would lead to failure. Do not trap the hammer under drill rig tracks or

Mincon – “Leaders in Rock Drilling Technology” Page 18
vehicle wheels which could cause bending and distortion of the hammer body. Failures caused by these actions cannot be supported
by warranty.
Take care when dismantling the hammer to make sure that parts and drill bits do not become detached and cause damage or personal
injury.
2.4.3 Dismantling Hammer to Change Drill Bit
When possible, dismantling the Hammer to change the drill bit is preferably best done in a workshop environment to avoid the risk of
injury and for cleanliness. Be careful to ensure that the drill bit and chuck are fully supported together so that there is no risk of them
becoming detached and causing injury. This can occur if the O Ring on the bit retaining rings is missing or damaged. Before fitting a
new drill bit visually inspect the splines of the chuck and the piston striking face to ensure that both are not damaged in any way. Fit
new bit as described in section 2.2.3 above.
2.4.4 Disassembly for Full Servicing of Hammer
Breakout the Chuck and Backhead as described previously. Unscrew chuck and remove bit and bit retaining rings. Unscrew the
backhead and check to see if the check valve and spring are operating correctly, and then remove them. Mark one end to identify
either the chuck or backhead end for reassembly latter.
Stand hammer up with the chuck end uppermost. Using a mild steel bar, tap the strike face of the piston to remove the air distributor
and inner cylinder. The steel make-up ring and lock ring should fall out during this process, if so remove them and continue until the top
of the air distributor is at the top of the wear sleeve. The hammer can now be placed flat on the ground or put up onto a suitable vice,
and using the mild steel bar, hit the piston strike face from the chuck end, to completely remove the air distributor, inner cylinder and
piston.
The piston retaining ring can be removed by using a mild steel bar and hitting the section opposite the gap on the ring which will ride up
the taper on the wear sleeve and come out. It can then be pulled out by hand.
2.4.5 Inspection
Prior to inspection, thoroughly clean all parts using a suitable cleaning agent. Diesel is not recommended for cleaning as it can cause
erosion to components, and damage to health.
All parts should be visually inspected for any signs of damage, wear or cracking. The inner cylinder, wear sleeve and lock rings can be
checked for unseen cracking by suspending them and lightly tapping with a screw driver. If they emit a ringing tone then they should be
sound. However, a dull flat tone if emitted may indicate cracking, and the part should be replaced.
Take particular care to check the internal bore of the wearsleeve for pick-up marks and galling. If these are present, the barrel of the
wear sleeve should be honed out, using a hand hone to remove them.
Inspect surface of the piston for pick-up marks and galling (usually caused through poor lubrication or the presence of contaminants)
and smooth out with emery paper or a hand held grit stone. Where galling of the piston has occurred, substantial heat has been
generated and quite often, micro cracking has occurred on the piston. In these cases, the piston should be replaced if there is evidence
of such cracking. Check the strike face of the piston for cracking or damage.
2.4.6 Checking Wear Limits
The performance of the hammer is dependent on the amount of wear the critical components have. These should be measured and
recorded in the Service log in the appendix. The service log gives the location of where measurements should be made. Depending
on how many parts need to be replaced, it may be economical to replace the hammer all together.
2.4.7 Reassembly
The hammer can be reassembled in the following manner, referring to the exploded view of the hammer in the appendix. Ensure all
components are liberally coated with good quality rock drill oil and threads with thread grease.
After identifying which end will be the chuck end, fit the piston retaining ring in this end. This can be pushed into place, using a small
bar or screwdriver to ensure that it is seated correctly. Place the bit retaining rings in and screw the chuck in place. Again make sure
to have the thin end of the bit retaining rings at the blow tube end of the bit.

Mincon – “Leaders in Rock Drilling Technology” Page 19
Turn wear sleeve over with the chuck on the floor, and drop the piston in with the strike face in first. Again ensure that fingers do not
get caught between the wear sleeve and the piston.
Place the three piece seating ring on the inner cylinder and secure in place with the seating ring O Ring. Insert The Air distributor into
the inner cylinder at the seating ring end and using a soft headed mallet, tap it into place so that it seats up against the top of the inner
cylinder.
Place the inner cylinder assembly into the wear sleeve, and tap down with a soft headed mallet. When beginning to hit the assembly,
ensure that it goes in square. Using a steel dolly, on top of the air distributor and inside the wear sleeve, drive the assembly into place
with a sledgehammer.
Place the lock ring in on top of the air distributor and then the Steel Makeup Ring on top of that. Insert the spring and check valve in
place and finally screw the backhead in place. With the backhead in place, there should be a small gap between the backhead and the
wearsleeve. This gap should be between 0.015” and 0.030”, and can be measured using a feeler gauge. If the gap is less than the
minimum, then the lock ring will need to be replaced. Protect the hammer as earlier described by internal lubrication.

Mincon – “Leaders in Rock Drilling Technology” Page 20
3 Appendix
3.1 HDD40 exploded view and Parts List
MINCONHDD40PARTSLISTAND
SPECIFICATIONS
Item Description Part no.
MINCON HDD40 HAMMER MHD301AS01
SONDE HOUSING ASSEMBLY MHS301AS01
1 SONDE HOUSING BACKHEAD MHS301BH01
2 Air Diverter Plug (Solid) MHS409DP01
Air Diverter Plug (1/8” Orifice) MHS409DP02
3 SPACER MHS304SM01
4 COMPRESSION RING MHS305LR01
5
O-RING
MHS321OR01
6
SONDE SPACER
MHS302SS01
7
O-RING
MHS321OR01
8
SONDE CARRIAGE
MHS303SC01
9
SONDE HOUSING SLEEVE
MHS311SH01
10
O-RING
MHS321OR01
11
SEALING SLEEVE
MHS306SL01
12
O-RING
MHS321OR01
13
O-RING
MHS321OR01
14
CARRIAGE GUIDE
MHS307CG01
15
O-RING
MHS321OR01
16
LOCATING PIN
MHS308LP01
17
BENT SUB
MHD301BH01
18
CHECK VALVE
MB302CV01
19
CHOKE
MB306CH01
CHOKE 1/8 (3.2mm) MB306CH02
CHOKE 3/16 (4.8mm) MB306CH03
20 SPRING MB503SP01
21 STEEL MAKE UP RING MB304SM01
22 LOCK RING MB305LR01
23 AIR DISTRIBUTOR MB307DR01
24
O-RING
MB321OR01
25
O-RING
MB322OR01
26
SEATING RING
MB309SR01
27
INNER CYLINDER
MB308IC02
28
PISTON
MB310PN01
29
WEAR SLEEVE
MHD311WS01
30
PISTON RETAINING RING
MB312PR01
31
BIT RETAINING SPACER
MB317BS01
32
O-RING
MB320OR01
33
BIT RETAINING RING
MB313BR02
34
CHUCK
MHD314CK01
35
BIT
13
1
2
3
4
5
6
7
8
9
10
11
12
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
14
33
34
35