Mounting a Cylindrical Grinding Wheel
Before installing a cylindrical grinding wheel, first inspect it carefully for cracks. Suspend the wheel and gently tap it with a wooden mallet. A wheel without cracks will produce a clear, ringing sound, while a cracked wheel will produce a dull sound. If any cracks or abnormal sound are detected, the wheel must not be used.
Parallel grinding wheels are generally mounted with flanges. The assembly mainly consists of the flange, end cover, screws, and a gasket (see figure below).
The bore of the cylindrical grinding wheel should have an installation clearance of 0.1–0.5 mm with the flange journal. If the fit is too tight, carefully scrape the wheel bore evenly with a scraper. Never force the wheel onto the flange. If the clearance is too large, the wheel and flange may become eccentric during installation, increasing imbalance. In this case, a layer of paper can be wrapped around the flange journal to reduce eccentricity. If the bore size differs significantly from the flange journal, a new flange should be prepared.
The flange support surfaces should be flat, and both flanges should have the same outside diameter. A 1–2 mm thick compressible gasket, such as heavy paper, should be placed between the flange and the cylindrical grinding wheel. The gasket diameter should be slightly larger than the flange diameter. Tighten the screws gradually in a diagonal sequence with uniform force to ensure even clamping pressure.
After installation, the cylindrical grinding wheel should be statically balanced before being mounted on the grinding machine spindle. During installation, check that the flange taper fits the spindle taper correctly. After the wheel has been trued and dressed, it should be removed and balanced again.
When removing the flange from the spindle, pay attention to the thread direction. To prevent the retaining nut from loosening during high-speed operation, the spindle thread is designed so that rotating the nut opposite to the wheel's direction of rotation tightens it. Most grinding machine spindles use left-hand threads. Never strike the flange or the wheel during removal, as this may damage the cylindrical grinding wheel or the spindle. For large flanges, use a dedicated puller. Before removal, place a wooden board under the wheel to prevent damage if it falls. First screw the puller into the flange thread, then tighten the puller screw to remove the flange from the spindle taper.
Dressing a Cylindrical Grinding Wheel
A newly installed cylindrical grinding wheel must be trued and dressed to eliminate shape errors that could affect wheel balance. Large wheels are usually rough dressed with a rotary dressing tool and then finish dressed with a diamond dresser. Both the wheel periphery and side face should be dressed.
When dressing the wheel periphery, avoid moving the wheel head excessively in the transverse direction. Distortion of the wheel head guideways may cause one-sided contact between the wheel and the workpiece during grinding, affecting the surface finish.
When grinding workpieces with shoulders, the side face of the cylindrical grinding wheel should be dressed into a slightly concave shape to reduce the contact area between the wheel and the workpiece. This helps prevent grinding burns and improves the accuracy of the shoulder face. During dressing, the wheel head can be rotated 1°–2° counterclockwise, or the side face can be dressed into a narrow annular concave profile as required.
