sentences:  The receiver and the stock are sometimes fastened indirectly through an intermediate piece (usually made of rigid materials such as aluminium alloy) known as a bedding block, which serves functionally as a larger pillar, a bedding surface and even recoil lugs.The contact interface on the stock may also be substituted by a metallic bedding frame known as a chassis, which is either embedded within the stock, or even completely replacing the stock like the lower receiver on many modern modular self-loading rifles.Skim bedding refers to an adjustment of a glass bedding job, usually after wear and tear from use, which consists of removing a small layer of the bedding material (usually up to around ) and adding new bedding material on top of that.