Usage:
Introduction
The hone group can be used to hone the inside diameter of hydraulic cylinders. This group can handle 63.50 to 294.00 mm (2.500 to 12.00 in) inside diameter cylinders.
Hone Tooling Assembly
Honing Head
Master Holder Set
(1) Holder. (2) Stones. (3) Guides.
1. From Chart A, select a stone set according to the bore size of the cylinder. Use stones (2) and guides (3) only as matched sets. Because of uneven wear, do not mix used stones and guides from different sets.
NOTE: 9U6749 Double - Length Master Holder is available for bore sizes of 203 - 305 mm (8 - 12 in)
2. If the bore size requires holders (1), install stones (2) and guides (3) in the holders and tighten the set screws. The stones and guides cannot be installed backwards because the mounting pins are different sizes. Otherwise, install the stones and guides directly into the stone support.
(4) Hone body. (5) Pinion. (6) Ring.
3. Pull back on release ring (6), tilt hone body (4) as shown, and remove pinion (5) from the hone body.
Hone Group (7) Stone Supports.
4. Use a stone support for bore sizes 152 mm(6.0 in) and larger. If the bore size requires the use of stone support (7), install the support on the hone body so the end marked " top" faces the hone drive shaft.
(4) Hone body. (8) Rack. (9) Hole marked "X".
5. Insert the master holder set into the holes marked "X" (9) on hone body (4) so racks (8) face the center of the hone body. If properly installed, the racks of opposing stones and guides will face each other.
6. Compress all the stones and guides into the body as far as they will go and install pinion (5).
7. Pull back on release ring (6), tilt and align hone body (4), and allow the tang to engage the pinion.
NOTE: The stone assembly and guides can be installed backwards. Be certain the stone assembly and guides are installed in the holes marked "X" with their racks facing the center of the hone body.
Shaft Extension
Hone Group
(1) Shaft extensions. (2) Feed assembly.
1. Depending on the length of the bore to be honed, one or a combination of shaft extensions (1) may be necessary.
2. Measure the length of the cylinder bore.
3. Select a shaft extension that will allow the honing head to reach the bottom of the bore without contact between feed assembly (2) and the open end of the cylinder.
4. Remove the four shaft bolts nearest the honing head and separate the shaft extension from the head.
5. Align the shaft extension drive tang and position the shaft extension between the honing head and the feed assembly. Install the extension with eight bolts rather than four.
Drill Support Stand
Drill Support Stand (1)
Because the hone drill motor is heavy and can create considerable torque, manual honing tooling should only be used when mounted in a fixture or support.
The 9U6476 Drill Support Stand (1) precisely guides the hone head into the cylinder bore. The stand's rail carries the weight of all honing components, absorbs torque, and is adjustable for cylinder bores of 63.5 to 406.4 mm (2.50 to 16.00 in). The stand can hone cylinders that have a stroke up to 3.6 M (12 ft)
Available in kit form, the 9U6476 Stand is a dealer-assembled kit that requires only attaching the legs by welding. The stand's carriage is pre-drilled to the hole pattern of 9U6400 and 9U6500 Drill Motors. An assembly of the stand is included at the back of this manual.
9U6500 and 9U6500 Drill Motors
9U6400 (110V) and 9U6500 (220V) Drill Motors are industrial-duty electric drtills that are expecially suited to the honing application. Both models have four (4) speeds: two (2) through a gear shifting mechanism and two (2) through an electric switch in the drill's handle. The speeds available are 115, 160, 190, and 260 RPM's (revolutions per minute). Select motor speeds through Chart {B} on page {11}.
Drill Motor Mounting and Assembly
(1) Feed assembly. (2) Universal joint. (3) Clamp coupler. (4) Thrust Coupler. (5) Drill motor. (6) Adapter plate. (7) Jam nut. (8) C Carriage. (9) S Screws.
1. As used to power the hone, the drill is modified for better access to the gear shift selector. Remove 4 screws (9) and pull the gear housing .25-.38 in. away from the drill. Rotate the housing 180° so the gear shift selector is on the same side as the drill's handle. Using the 4 screws, install the housing. If the housing is pulled more than .25-.38 in., the motor's armature may be pulled from the brushes. In that case, the brushes will have to be removed before the armature can be installed.
2. Remove carriage (8) from the carriage stand. Remove handle adapter plate (6) from the drill and assemble either 9U6400 or 9U6500 Drill Motor (5) to carriage of the drill support stand.
3. Remove the stop from the end of the carriage rail and slide the carriage/motor assembly onto the carriage rail. If the carriage does not slide easily, loosen the large jam nuts (7) and adjust the roller studs to add more rolling clearance.
4. Align the tang of the Morse taper drive shaft of 9U6467 Thrust Coupler (4) with the slot of the Morse taper adapter and slide the coupler assembly onto the output housing of drill motor (5). Seat the Morse taper by tapping the coupler assembly with a plastic mallet.
5. Remove the hex adapter from the universal joint (2). Remove the drive pin from the yoke adapter (see sketch). Thread the modified yoke adapter into the universal adapter. Thread the universal joint assembly into the feed assembly.
6. Insert the end of the modified yoke adapter into the clamp coupler (3) and tighten ALL screws.
7. If other motors are used, a universal joint must be used to allow for misalignment if the motor is installed in a rigid fixture.
Barrel Cradle Stand
(1) Barrel cradle stand. (2) Oil tank.
Honing can create considerable torque. The 9U6477 Barrel Cradle Stand (1) provides a method of support and clamping that prevents the cylinder from rotating. It can be used for honing all sizes of cylinders. The barrel cradle stand is a dealer-assembed kit that requires only attaching the legs by welding. The stand uses ratchet-type load binders for clamping and has one fixed and one movable "V" block. The stand was designed to work in conjunction with 9U6759 Oil Tank (2) and comes complete with fittings and a supply hose. It does not include the caster base as shown (optional caster base 4C3896). An assembly drawing of the stand is included at the back of this manual.
It is recommended that after being located in a suitable work area the stand be anchored to the floor.
As an alternative, select either a sturdy workbench or a table, preferably one fabricated from plate steel. The bench must be able to support the weight of the cylinder. Avoid the use of sheet-steel benches.
Honing Oil Supply
A continuous supply of honing oil to the honing head is essential to keep the stones cutting and the guides lubricated. 9U6759 Oil Tank has been designed for use with 9U6477 Barrel Cradle Stand and is equipped with a 300 gallon per hour pump. The tank comes with necessary fittings and a length of 1/2 in ID hose.
Random scratches in the bore may be caused by honing grit being trapped by between the cylinder wall and the honing stone. One method of improving the surface finish is to filter the oil before it is pumped to the honing head. Filtering the oil can be done by positioning a 7W5317 Air Filter Element in the basin of 9U6759 Tank so that discharged oil from the cylinder tube is strained through the element before it drains back into the tank. Additionally, position several 8M7160 Magnets around the drain into the tank to attract stray metal shavings before they get to the pump pick-up.
Regardless of the pumping system devised, configure the system so that oil draining from the cylinder is collected in a sump. The sump should contain baffles to cause particulates to settle out of the oil before it is picked up by the pump. Arrange the pump pick-up so it is above the bottom of the sump.
Honing Procedure
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If the hone head falls free of the cylinder assembly, personal injury or damage to the honing equipment may result. Do not allow the stones to extend more than 25.4 mm (1.00 in) past the end of the cylinder assembly. Do not remove the hone head from the cylinder assembly while the head is rotating. Expanding the stones too aggressively may cause them to "grab" and can result in broken stones and/or drive mechanism breakage. Use caution when expanding the stones. |
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1. Place the honing head in the end of the cylinder assembly.
2. Set the rear carriage travel stop (can be a C-clamp or locking pliers) so the head does not extend more than 25.4 mm (1.00 in) past the end of the cylinder assembly. If possible, set a forward carriage travel stop so the stones don't contact the closed end of the cylinder assembly.
3. Expand the stones in the bore by turning the handwheel counterclockwise (viewed from behind the drill motor) until the stones contact the bore. Check to see that the stones are tight against the bore and the guides are loose. Turn the handwheel 1/4 to 1/2 turn clockwise. If the guides are not loose, file up to 1.00 mm (.039 in) from each guide to relieve guide pressure and speed up stock removal.
4. Start the pump for the honing oil supply.
5. After a stream of oil flows from the cylinder assembly, start the hone rotating in a clockwise direction (viewed from behind the drill motor).
6. Slowly stroke the hone into and out of the cylinder bore. Be alert for changes in the bore diameter. The diameter will vary along the length of the bore due to damage or different amounts of wear.
7. Initially the stones will be loose in the bore and will "rattle". To expand the stones, apply slight stopping pressure to the handwheel (or turn the handwheel counterclockwise) while it is rotating.
8. Increase the stroke speed up to 76 to 102 mm (3 to 4 in) per second. Make an effort to ensure the "stroke-in" time (or speed) is the same as the "stroke-out" time. Varying stroke times will cause uneven stone and guide wear.
9. As the bore gets larger and the stones wear, the stones will begin to rattle again and the head will be loose in the bore. Expand the stones by turning the handwheel counterclockwise. The stones will be cutting efficiently when it takes considerable force to stroke the hone at a rate of approximately 76 to 102 mm (3 to 4 in) per second.
10. If tight spots are felt during stroking, dwell at those areas until the bore gets larger. Otherwise, do not dwell at either end of the stroke unless the intent is to enlarge a tight spot. Gradually lengthen the stroke as the bore becomes straighter. Do not hone in one area for an extended period of time to prevent excessive heat build-up.
11. Stop honing at 5-10 minute intervals to inspect and measure the bore and determine if all bore damage has been removed. To avoid creating length-wise bore scratches when the honing head is removed from the bore, plan to stop the honing operation so that on its outward stroke, the honing head finishes at the open end of the cylinder assembly.
12. When the roughing stones have removed all damage and have reconditioned the complete length of the bore, measure the bore. If the bore is less than 0.25 mm (.010 in) oversize, continue to recondition the bore using finish stones.
If the rough honing process has removed all scratches but also made the bore more than 0.25 mm (.010 in) oversize, standard seals will not work to seal the cylinder. Cylinders in this category can be salvaged by honing to 0.76 mm (.030 in) oversize and using oversize seals.
13. Use finishing stones and hone the complete length of the bore to get a surface finish of 0.8 micrometers (32 microinches).
14. Allow the honing oil to drain from the cylinder. Move the cylinder assembly to a solvent tank and thoroughly flush all honing grit from it.
15. Clean the cylinder assembly as described in the Honing Operations section.
Honing Operations
Honing Head rpm (revolutions per minute)
For each bore size, the hone must be operated within a rpm range in order for the stones to "cut" correctly and not wear too rapidly. In general, the larger the bore, the slower the rpm.
Determine the proper head rpm by dividing the bore size in millimeters into 30,000 (or the bore size in inches into 1200).
Example: 30,000 ÷ 101.6 mm (bore) = 295 rpm 1200 ÷ 4.00 in (bore) = 300 rpm
If either a 9U6400 or 9U6500 Drill Motor is used, select a motor rpm from Chart B. If the motor rpm does not match the rpm calculated by the formula, select the next higher motor rpm.
Chart B Bore Size and Honing RPM (using 9U6400 or 9U6500 Drill Motor)
Honing Head Feed/Crosshatch
The hone must be stroked along the length of the bore in order to refinish the bore uniformly. Stroking the hone at a rate of 76 to 102 mm (3 to 4 in) per second will cause the stones to wear evenly. A stroke speed that is too slow will cause the stones to wear more in one area than another and cause inconsistent bore sizes. Localized honing should be avoided unless the intent is to enlarge a "tight" (undersize) area.
A correct stroke speed will produce a crosshatch pattern. The diagonal scratches of the pattern will be formed at an included angle of approximately 105 - 125 degrees. The crosshatch pattern is determined by a combination of rotational speed (rpm) and traverse speed (feed). In general, a larger bore requires both less rpm and a lower feed rate while a smaller bore can handle a higher feed rate and higher rpm.
Stroke Length
When stroking, use care at both ends of the cylinder assembly. The stones should extend past the open end of the cylinder assembly but not more than 25.4 mm (1.00 in) or 1/3 the stone length. Hone the complete length of the bore, but do not allow the stones to contact the closed end of the cylinder assembly or damage to the stones may result.
Surface Finish
A measurement of surface finish given in micrometers or microinches is an indication of the relative "roughness" of the finish. A "low" micrometer (0 - .8) or microinch (0 - 32) number called out on a print specifies a relatively smooth finish. "Higher" numbers indicate rougher finishes. The most accurate method of determining the roughness of a surface is by using a profilometer or surface finish tester. Such instruments calculate the roughness average (Ra) of a surface over a given length. A Profilometer will be available from the Caterpillar Service Technology Group in 1994.
A surface finish of .80 micrometers (32 microinches) or smoother is necessary for proper seal and cylinder performance. Surfaces rougher than .80 micrometer (32 microinches) will cause accelerated seal wear, leakage, and erratic cylinder operation.
After rough honing using Aluminum Oxide stones of 150 grit, install Silicone Carbide finish stones of 400 grit and hone for 10-20 strokes (1 stroke = in & out).
The number of strokes will vary with the cylinder bore size and length. Determine the smoothness of the bore. If the finish is judged to be .8 micrometers (32 microinches) or smoother, honing is complete. Do not continue to hone if the finish is .8 micrometers (32 microinches) or smoother because any additional honing consumes unnecessary time and honing consumables. Proceed to clean the cylinder.
Honing Oil
9U6484 Honing Oil is offered by CSTG and is formulated for honing the type of steel used in hydraulic cylinder tubes. 9U6484 Honing Oil ensures fast cutting and will minimize galling in addition to providing lubrication to the stones and guides.
NOTE: 9U6484 Honing Oil is not a cleaning fluid. Honed cylinder tubes must be cleaned or flushed prior to re-assembly. Refer to the following section.
Do not use 5P8615 Honing Oil when honing steel hydraulic components. 5P8615 Honing Oil is formulated for honing cast iron parts.
Do not use lubricating oil, cutting oil, or water soluble oil. Do not dilute the oil. Consistent results cannot be expected unless full-strength, recommended oil is used.
Cleaning
The honing process creates a large quantity of abrasive particles that must be cleaned from the cylinder before it is resealed.
The abrasives are either stone particles, the binder used to hold the stone particles together, guide material, or metal shavings from the cylinder bore. Abrasives of any type cause accelerated wear to hydraulic cylinder seals as well as other hydraulic system components.
Following honing, allow the honing oil to drain from the cylinder assembly. Remove the cylinder assembly to an appropriate area and wash the cylinder assembly bore and OD using high-pressure steam and/or soap solution.
Hydrosolv 4165, a soap product available from Caterpillar Service technology Group, is well suited to parts cleaning applications. Hydrosolv 4165 contains agents that provide rust protection for up to 6 weeks and is available in 1 gallon (1U8812), 5 gallon (1U5490) and 55 gallon (8T7570). In addition, CSTG will be announcing new Cleaning equipment in the near future. Watch for announcements detailing its applications and availability.
Concentrate the wash on confined areas such as ports, internal threads, and interior weld parting lines. Rinse the cylinder assembly with water. Wipe a clean white towel or paper towel across the bore. The bore is "clean" if the towel is not discolored after being wiped through the bore. Repeat washing and rinsing the cylinder assembly until the towel is not discolored.
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Pressure air can cause personal injury. When using pressure air for cleaning, wear a protective face shield, protective clothing and protective shoes. The maximum air pressure must be below 205 kPa (30 psi) for cleaning purposes. |
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Following a final rinse, dry the cylinder assembly using pressure air.
NOTE: The possibility of flash rust during drying is minimized if the cylinder is warmed during the cleaning process causing any water to evaporate.
If the cylinder will not be assembled for some time, coat all exposed metal surfaces with clean hydraulic oil.
Chart C Honing Troubleshooting Guide
