Diamond rolls are high-precision tools and must be treated as such. The following are recommended procedures for assembling a roll on a spindle shaft:
• Standard roll/spindle assembly tolerances. Standard toleranced assemblies refer to rolls with bore tolerances of 2.5 to 7 pm over nominal mounting on shafts with nominal to
2.5 pm undersize, giving an average “loose” fit of 5 pm. The shaft itself should have a runout condition of <1.25 pm truth in running (T. I.R.), and after assembly in the spindle bearings of <2.5 pm T. I.R.
• Diamond rolls should be mounted in a clean environment removed from the production area by a person properly trained to deal with the tolerance level involved.
• A fine grit oilstone should be rubbed lightly on the end faces of the diamond roll and any spacers to ensure that there are no burrs or raised metal due to previous handling.
• A film of gauge oil should be sprayed in the bores and then wiped clean with a lint-free cloth to ensure the absence of dust or grit before assembling.
• The shaft should be treated as step c.
• Carefully align the diamond roll bore to the shaft. It is critical that the roll be started in a straight fashion. Otherwise, the roll can jam on the shaft before engaging the full bore.
A slight lead of 5 pm over 40 mm is extremely helpful. The diamond roll should slide down the shaft with minimal pressure until it bottoms out.
• An aid to ease of assembly is to place the roll in warm water (40°C to 60°C) to minimally expand the bore and ease assembly. DO NOT use a hot plate or hot air gun as this will distort the roll or, in the case of reverse plated rolls, melt the alloy holding the diamond layer to the core.
• Never force the diamond roll onto the shaft if unable to assemble. Inspect the bore and shaft for actual size or inspect for “raised” metal contact.
• Complete mounting by assembling clamping nut or mounting screws, using care not to overtighten, to approximately 130 N. m (100 ft. lb) on nut or 4 N. m (3 ft. lb) on typical 10-32 screw.
• Inspect assembly for runout by rotating in bearings before mounting in machine (if possible). Runout condition should not exceed 5 pm T. I.R. on diamond rolls using diamond free, indicating bands at ends of roll.
For disassembly, the roll should again be removed from the shaft in a clean environment, away from the production area. The shaft end and diamond roll end faces should be wiped clean to prevent dirt becoming trapped during removal and scoring the shaft or roll bore. If proper assembly procedure was followed, removal should be accomplished by simply sliding diamond rolls off shaft. Never force the roll especially by the use of hammers of any kind.
• Line-fit roll/spindle assembly tolerances. Line-fit toleranced assemblies refer to rolls with bore tolerances of nominal to -2.5 pm under nominal mounting on shafts with nominal to 2.5 pm undersize, giving an average fit of zero or linefit. The shaft itself should have a runout condition of <1.25 pm T. I.R., and after assembly in the spindle bearings of < 2 pm T. I.R.
• It is generally recommended that the roll manufacturer assemble and disassemble line — fit rolls. It is mandatory that the assembly be carried out in a clean environment, preferably temperature controlled, by trained individuals.
• A fine grit oilstone should be rubbed lightly on the end faces of the diamond roll and any spacers to ensure there are no burrs or raised metal due to previous handling.
• A film of gauge oil should be sprayed in the bores and then wiped clean with a lint free cloth to ensure the absence of grit before assembling.
• Chill the shaft for approximately 30 minutes using cold tap water or ice packs to contract the mating diameter. Warm the diamond roll in hot water (65°C max) for 2 to 5 min to minimally expand the bore.
• Quickly, but carefully, align the diamond roll bore in the shaft and slide the roll down until bottomed out.
• Turn the roll slowly on the shaft, maintaining a downward pressure, until temperature is equalized and the diamond roll becomes immovable.
• Complete mounting by assembling clamping nut (using care not to overtighten) to approximately 130 N. m (100 ft. lb). Locking screws are not recommended because of the lack of time to accurately align the bolt pattern.
• Inspect assembly for runout by rotating in the bearing assembly before mounting in the machine (if possible). Runout should not exceed 2.5 pm T. I.R. on the diamond rolls using the diamond-free indicating diameters at the ends of roll.
For disassembly, the roll should again be removed from the shaft in a clean environment, away from the production area. The shaft end and diamond roll end faces should be wiped clean to prevent dirt becoming trapped during removal and scoring the shaft or roll bore. Cool assembly in cold tap water or with ice packs for 30 min, then run hot water over the diamond roll only before quickly removing the diamond roll assembly. Never force the roll, especially by the use of hammers of any kind.