Operation & Service Manual for the DTH Hammer
Contents
1. Operation amp Service Manual for the Wiincon SDH DTH Hammer Thank you for choosing the Mincon 5DH HD Down the Hole hammer Please read this manual carefully before using your hammer in the interests of safety warranty and best operational care The Mincon 5DH HD is ruggedly built with a hardened wear sleeve to withstand the stresses of drilling in the most extreme conditions However on the inside it is a precision tool with care taken in manufacture to ensure that the components meet finely matching tolerances to provide fast drilling reliability and efficient use of air without waste With correct care your Mincon 5DH HD hammer should provide you with top performance reliability and long service life Warranty is provided by Mincon as per the warranty section 5 Q Please keep this instruction manual as a permanent part of your DTH Hammer Q The specifications and instructions contained in this manual are based on the up to date information as at publication date Copyright 2002 All rights reserved by Mincon TABLE OF CONTENTS Table of Contents 2 1 Installation and Operation 3 EE u dois pado OC er ERE 3 1 2 Hammer a u P m 3 3 1 2 2 Commissioning M 3 EXE oo Fc M 4 PEE 5 L3 Servici2. 85 11mm C C A Piston OD 3 346 85 00mm D B D gt 0 010 Narrow 0 25mm End NS SS SASS A AN N D SS S SS OM Page 12 DISTRIBUTOR PROBE PISTON ID CLEARANCE Part As New Dimension As Wear Measured Discard Measured Clearance Clearance Distributor A 1 248 31 70mm C A Probe OD gt 5 Piston ID 1 256 31 90mm D B D C D 20019 0 25mm Narrow End IX 5 SE OUTSIDE DIAMETER WEAR LIMITS Description Wear Limit As Measured Wearsleeve Reverse Dimension 4 570 116 0mm Wearsleeve Discard Dimension 4 400 112 0mm Note 1 If no evidence of significant air pressure drop or if wearsleeve is wearing evenly on both top and bottom end recommendation is to not reverse wearsleeve Note 2 Chuck should be replaced when wear transfers to wearsleeve Page 13 4 Warranty Mincon DTH HAMMERS Warranty Mincon warrants that the Mincon DTH Hammers and spare parts therefore manufactured by Mincon and delivered to the initial user to be free of defects in materials or workmanship for a period of 3 months after initial operation or 6 months from the date of shipment to the initial user whichever occurs first Mincon may elect to repair the defective part or issue full or partia
3. 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 1 3 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 pisto
4. pint 1 4 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 Page 3 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 1 2 3 Lubrication It is vital for DTH 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 Litres Hour 05 1 15 20 25 35 0 t2 Air Volume gt NIWAN 1 2 3 4 5 US Pints Hour In wet drilling above 2gpm 8 Ipm the oil consumption should be doubled There should be visual evidence of oil around the drill bit shank and within the tube joints when changing tubes Pressure Bar 6 9 27 6 34 5 Ll Ll l 120 48 9 100 r 37 8 80 ISO320 26 7 60 715 6 150150 178 28 9 100 200 300 400 500 Pres
5. ainst 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 1 2 Hammer Care 1 2 1 Storage If you intend to store the Hammer We recommend that 12 pint 1 4 litre of good quality rock drill oil be poured into the hammer to protect it The oil should be poured through the backhead and by using a long screwdriver inserted into the backhead the check valve can be depressed to allow the oil to run down into the piston chamber 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 1 2 2 Commissioning Always use reputable drill bits in good condition Using overrun bits will effect penetration rates and reduce chuck life significantly due to excess cuttings wash Coat the drill bit shank and the hammer threads with grease for protection and easier dismantling Prior to use lubricate the hammer with
6. ater Use only filtered water free from contamination Bit retaining rings have been assembled upside down causing backhammer and damage to bit piston Ensure bit rings installed correctly to allow maximum drop out of bit 4HR 5DH HD and 5DH only Page 10 3 Appendix 3 1 DTH Hammer exploded view and Parts List MINCON SDH HD PARTS LIST AND SPECIFICATIONS p Mincon 5DH HD Hammer 3 API MDX501AS04 Mincon 5DH HD Hammer 2 3 8 API MDX501AS03 4 eme asma a Sei sro A __ ama 8 Lu 10 2 12 11 3 2 Mincon 5DH HD Service Log WEARSLEEVE PISTON CLEARANCE Part As New Dimension AS Wear Measured Discard Measured Clearance Clearance Wearsleeve A 3 936 99 98mm C A gt 0 010 Piston OD 3 931 99 85mm D B D C D 0 25mm Large End NS im N SSS SSSS Ee s SS TISSE NN D Chuck end WW CG CG KR SS Wor 1 ase j i INNER CYLINDER PISTON CLEARANCE Part As New Dimension As Wear Measured Discard Measured Clearance Clearance Cylinder ID A 3 351
7. blem Possible cause Remedy LOW Exhaust tube not fitted Check exhaust tube extension and if tube is PENETRATION HIGH properly lose PRESSURE Contamination in hammer Open hammer and clean the obstruction Too much water injection Reduce level of water in flow ROUGH OR ERRATIC Too much feed pressure Set the feed pressure until the rotation starts to OPERATION bind Then back off the feed pressure until the rotation runs smoothly Rotation speed too slow Place chalk mark on drill rod and check the advance revolution If greater than 12mm per revolution increase rotation until the advance per revolution is a maximum of between 10 12mm Worn bit bearing Replace bit bearing Too much water injection Reduce level of water in flow LOW PENETRATION Worn drill clearances Inspect piston inner cylinder wearsleeve air LOW PRESSURE distributor probe and bearing against discard measurements and discard as necessary Lack of oil Ensure there is an oil film coming from bit spline and bit parts Place cardboard under bit to check DRILL RUNNING Bit is worn badly Replace bit OFF BOTTOM reducing clearance between hammer and hole Too much water injection Reduce level of water flow EXHAUST TUBE Bearing I D is worn Replace bearing BREAKING Erosion of exhaust tube Water strikes the exhaust tube in the piston strike position when using in the drill Reduce the flow of water CRACKED WEAR Abuse of wearsleeve Avoid welding heating or hammering SLEEVE wearsl
8. conditions and prevent heat damage 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 drill tubes 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 Page 5 1 3 Servicing 1 3 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 1 3 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 tim
9. eeve Place breakout wrenches 100 mm from ends of wear sleeve Worn wearsleeve Casing has worn beyond the discard point Measure casing O D approx 75mm 3 from chuck end and backhead end and replace if necessary Corrosion Ensure a pH neutral water well filtered and free from contaminants is used in the drill Corrosion usually accelerates from the threaded area or any undercut area PISTON CRACKED Lack of lubrication causes Check lubricator and ensure oil film on the bit OR BROKEN micro cracks leading to splines and blow holes breakage Page 9 Problem Possible cause Remedy PISTON CRACKED Drill badly bogged which Flood tool with water when bogged Use OR BROKEN can cause wearsleeve to digout sub above hammer in such conditions distort causing functional heat and cracks Feeding hard through Use light feed and ensure the hole is kept clean voids on broken ground and consolidated Use foam or mud if can cause wearsleeve to necessary distort causing heat and cracks Abuse of wearsleeve Avoid welding heating or hammering wearsleeve Place breakout wrenches 100 mm from ends of wear sleeve PISTON STRIKE END Not enough down force Increase feed until rotation binds and pressure BREAKING pulses and then back off until the rotation and pressure becomes smooth Contamination from excess water injection causes pitting in the piston face and external failure Avoid excessive water Use only pH neutral w
10. ely damage to the hammer components and threads 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 A backreamer sub may help prevent jamming in bad ground
11. es to dismantle DTH 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 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 1 3 8 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 s
12. ising out of this sale or any breach thereof or any defects in or failure of or malfunction of the Mincon DTH Hammer or spare parts Warranty will be voided where There is evidence of damage resulting from insufficient or incorrect lubrication There is evidence of misuse through the application of heat welding or of being struck There is evidence of distortion or bending however caused There is damage caused as a result of using incorrect servicing tools or procedures If it is evident that the hammer or its components have achieved a reasonable proportion of their anticipated life Page 14
13. l credit towards the purchase of a new part The extent of credit issued will be determined on a pro rata basis bearing in mind the service life of the defective part against the normal service life of that part The part will be replaced or repaired without charge to the initial user at the place of business of an authorized Mincon distributor during normal working hours The user must present proof of purchase at the time of exercising the warranty The warranty applies only to failures resulting from defects in the material or workmanship and does not apply to failures occurring as a result of abuse misuse corrosion erosion negligent repairs and normal wear and tear Failure to follow recommended operating and maintenance procedures which result in component failure will not be considered for warranty This warranty is in lieu of all other warranties other than title expressed or implied Limitation of Liability Mincon will not accept any remedies to the user other than those set out under the provisions of warranty above The total liability of Mincon or its distributors with respect to the sale of DTH Hammers or spare parts therefor whether based on contract negligence warranty indemnity or otherwise shall not exceed the purchase price of the product upon which such liability is based Mincon and its distributors shall in no event be liable to any party relating to this sale for any consequential indirect special or punitive damages ar
14. n 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 1 3 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 Page 7 Where the reverse wear limit has been reached the outer diameter at the chuck end of the wear sleeve the hammer can be reassembled with the backhead end becoming the chuck end Additionally if the internal running surface in the wear sleeve for the piston is excessive the wear sleeve can be reversed 1 3 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 su
15. ng u u aaa REED VEOHAE VERE EE EVER YHTVEEFRERAAEU C CURED OFF VENE RR MES 6 LO General iania 1 3 2 Opening Chuck and Backhead 6 1 3 3 Dismantling Hammer to Change Drill Bit 6 1 3 4 Disassembly for Full Servicing of Hammer 7 13 58 UID IUIS H9 7 1 3 6 Checking Wear Limits 7 13 7 8 2 Trouble Shootinsg 9 3 09090000000000000000000000000000000000000000000000000000000000000000000 11 3 1 DTH Hammer exploded view and Parts List 11 3 2 Mincou 5DH HD Service Los 12 4 sassssescesscssssssesaccaceescostieasseceaensscsuseseasssviossecseae Page 2 1 Installation and Operation 1 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 Down the Hole percussive hammer emits noise and you should therefore take every precaution to safeguard your hearing ag
16. o 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 Place chuck onto the bit and secure with the bit retaining rings above the chuck Make sure to have the thin end of the bit retaining rings at the blow tube end of the bit Liberally grease the threads on the chuck Screw chuck into wear sleeve by hand alternatively if using the rig to screw chuck on ensure that no cross threading occurs Prior to use place bit in a bit basket and torque up chuck This is essential as the chuck can loosen if not properly torqued and premature chuck failure can occur Page 6 1 3 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
17. re to have the thin end of the bit retaining rings at the blow tube end of the bit 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 Page 8 2 Trouble Shooting Pro
18. sure PSI 40 m gt 20 T Ambient Temperature O Ju iqury 20 The recommended grade of oil is dependent on the ambient temperature in which drilling is taking place as well as the operating pressure As 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 it s components Hydraulic oils engine oils gear oils and diesel are not recommended for lubricating DTH hammers Page 4 1 2 4 Operation Be sure to familiarise 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 lik
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