PIN AS 2969586 - Caterpillar

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 rpmIf 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)
9U6400 and 9U6500 Drill MotorHoning 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