An end mill has a shank and a cutting edge main body portion. The cutting edge main body portion is provided on the shank and has a coolant supply path. The cutting edge main body portion includes a trailing end surface on a side of the shank, and a leading end surface opposite to the trailing end surface. The coolant supply path has a tapered portion which widens in a direction from the trailing end surface toward the leading end surface.

According to one aspect of this disclosure, a grooving tool is provided. The grooving tool has a body with a plurality of recesses. Plural inserts assembled into each of the recesses. The recesses include a cutting edge for forming grooves in an engine cylinder wall when rotated in one rotational direction. The insert also includes a peening surface extending in the opposite rotational direction from the cutting edge for deforming the upper edges of the grooves when rotated in an opposite rotational direction.

According to one aspect of this disclosure, a grooving tool is provided. The grooving tool has a body with a plurality of recesses. Plural inserts assembled into each of the recesses. The recesses include a cutting edge for forming grooves in an engine cylinder wall when rotated in one rotational direction. The insert also includes a peening surface extending in the opposite rotational direction from the cutting edge for deforming the upper edges of the grooves when rotated in an opposite rotational direction.