The present invention provides rotatable cutting tools having washers with changing thicknesses. One side of the washer has a tapered surface that increases the thickness of the washer from the inner radius towards the outer radius, resulting in a thicker portion at the outer edge of the washer. The rotatable cutting tool may also have a bit with a tapered surface. The tapered surface of the bit may be structured and arranged to engage with the tapered surface of the washer. The rotatable cutting tool may also include a holder such that the assembled rotatable cutting tool includes the washer between the bit and the holder with the bit inserted into the holder and washer.

Cutting tools (14) and cutting tool assemblies (10) include a friction ring (79). The friction ring (79) is provided in (disposed/secured within) a retaining groove (32) of a shank (30) of the cutting tool (14). The friction ring (79) can be formed from a resilient material or materials (150). The friction ring (79) can be secured in the retaining groove (32) by a retainer ring (80). The cutting tools (14) can also include a shank (30) having an increased diameter to provide increased strength and allow for a heavier cutting portion (28) of the cutting tool (14). The cutting tools (14) and cutting tool assemblies (10) can also include a washer (100) fitted about the shank (30) and positioned adjacent to a back side (26) of the cutting portion (28) of the cutting tool (14) for stabilizing the cutting tool body (22) in relation to a cutting tool holder (12).

A combination bit and bit holder assembly includes a bit holder having a forward body portion and a shank. The forward body portion includes an upper end and a lower end. An insert is mounted in the bore of the upper end of the body portion. The insert also includes a central bore that receivingly retains a receiving cup. The receiving cup includes a bottom portion and an annular flange that extends from the bottom portion and defines a hollow forward portion. A bit is mounted in the hollow forward portion of the receiving cup which is configured to have a ductility that provides impact absorption to the bit.

The invention relates to a bit holder for an earth working machine, in particular a road milling machine, having a support body onto which a holding portion having a bit receptacle, and oppositely an insertion projection, are shaped. The holding portion is terminated at the end by a wear surface, and the bit receptacle by a centering receptacle opening in bevel fashion toward the wear surface. A centering height, measured in the direction of the longitudinal center axis, between an end of the centering receptacle and the wear surface or a maximum point of a projection projecting beyond the wear surface, is designed in such a way that the ratio between the inside diameter D.sub.i of the bit receptacle and the centering height is less than 8; and/or that the centering height is greater than an axial play of a round-shank bit installable in the bit holder; and that the support body comprises, on its side facing away from the holding portion, at least two bearing surfaces that are at an angle to one another and form a bearing-surface pair.

Reduced wear on the holding portion and a reduced load on the insertion projection, and thus an extension of the service life of the bit holder, are achieved.

A retainer for a rotating bit and/or pick that includes a slot extending from a forward end of the retainer to a distal end of the retainer. The slot includes a gap profile formed by the configuration or design of a first radial end surface of the slot and a second radial end surface of the slot. The retainer includes a dual corner break formed by a first angled surface extending from the distal end of the retainer to the first radial end surface of the slot and a second angled surface extending from the distal end of the retainer to the second radial end surface of the slot. In additional embodiments, the retainer can include any of or any combination of a lead-in chamfer at the distal end of the retainer, a relief notch extending from the distal end of the retainer, and a compression slot extending from the relief notch. The retainer may be used independently with the rotating bit or it may be used in conjunction with nearly butted or solid generally cylindrical hollow spacers and/or washers.

The invention relates to a bit holder for an earth working machine, in particular a road milling machine, that comprises a bit receptacle in the region of a working side of a support member and that indirectly or directly carries an insertion projection on an insertion projection side of the support member, the support member comprising two stripping surfaces [first or second stripping surfaces] that form a stripping surface pair and are at an angle to one another. In order to achieve a stable and long-lived configuration with such a bit holder, provision is made according to the present invention that the support member comprises at least one further stripping surface that is at an angle to the two stripping surfaces of the stripping surface pair.

A cutting tool holding device, which is for holding a cutting tool, includes a base, a holder, and a limiting set, wherein the holder is disposed on the base, and the limiting set is disposed in a non-circular channel of the base. A connecting shaft portion of the holder is for inserting into a storage hole of the base, wherein the connecting shaft portion includes a shaft body and at least one positioning portion, and the non-circular channel includes an abutting member and a bolt. The bolt is passed through the abutting member, wherein the abutting member is moved to an opening hole of the storage hole along an axis by rotating the bolt so as to push the positioning portion and abut the shaft body.

A cutting tooth system includes a plurality of substrates, each having a base for attaching to the cutting wheel, and an outer surface opposite the base. A plurality of tooth pockets are integrally formed in the substrate, each tooth pocket having a tooth receiving aperture extending through the outer surface and into the substrate. A cutting tooth has a pocket engagement portion configured for being received in a mounting pocket. The pocket engagement portion defines a pocket engagement length and a shank defining a shank diameter. A cutter portion extends from the pocket engagement portion.

A bit assembly includes a base block and a bit having a forward body portion and a shank. The bit includes a diametrically expanding retainer circumferentially disposed around a shank of the bit adapted to maintain the interference contact between the bit and the base block as the diameter of a bore of the base block increases from use. The bit assembly also includes a sealing gasket that forms a force fit between a washer disposed about the shank of the bit and the base block.

The invention relates to a tool for securing on a tool holder of a machine tool for machining vegetable and/or mineral materials, comprising a tool body which is equipped with a machining attachment that points in a tool feeding direction and comprises a cutting region, in particular a cutting element, and on which a fitting element for meshing with a mating element provided on the tool holder is formed on a support surface facing the tool holder. The dependability and operational reliability when using a machine tool can be ensured if the fitting element has at least two molded regions with different contour regions over the vertical course of the fitting element with respect to the support surface.