Abstract:
A machine tool assembly including a body component, a head component and a fastener. The body and head components respectively include a body hole and a head hole. The fastener is configured to secure the head component to the body component via insertion through the head hole and attachment to the body hole. The head hole includes a head fastener retention arrangement for preventing unintentional ejection of the fastener therefrom.

Description:
FIELD OF THE INVENTION 
       [0001]    The subject matter of the present application relates to machine tool assemblies configured with fasteners for securing head components to body components, and more particularly configured for swift removal of the head components from the body components. 
       BACKGROUND OF THE INVENTION 
       [0002]    Machine tool assemblies, used for machining materials such as steel, have been extensively developed over the last century, with each incremental development further improving the efficiency thereof in a highly competitive worldwide marketplace. 
         [0003]    Machine tool assemblies often comprise detachable, replaceable components to improve cost efficiency and/or usability. For example, rather than produce a large monolithic tool made of cemented carbide, a tool of a cheaper material with only a small connectable element (e.g., a cutting insert) of cemented carbide can be made, the smaller element being replaceable when worn, thereby increasing overall cost efficiency of the tool materials. Nonetheless, production, assembly and disassembly of connectable components are not without associated difficulties and costs. 
         [0004]    A known problem, in particular for small machine tools, is that small dynamic fastening elements (hereinafter “fasteners”, e.g. screws) can accidentally fall to the ground during attachment or detachment of components. 
         [0005]    One possible solution can be to use a retention element such as a circlip. 
         [0006]    U.S. Pat. No. 8,479,622, assigned to the present Applicant, discloses a machine tool assembly having a replaceable tool head and also, inter alia, mentions a disadvantage of falling parts. 
       SUMMARY OF THE INVENTION 
       [0007]    In accordance with a first aspect of the subject matter of the present application, there is provided a machine tool assembly comprising: a body component; a head component; and a fastener comprising a fastener head and a fastener shank extending therefrom, the fastener shank having an external shank threading; the body component comprising: a first body surface; a body fastening arrangement formed on the first body surface; and a body hole opening out to the first body surface; the head component comprising: first and second head surfaces; a head fastening arrangement formed on the second head surface and configured to interlock with the body fastening arrangement; and a head hole opening out at a first head hole end to the first head surface and at a second head hole end to the second head surface; wherein: the head hole is formed with an internal head threading and the body hole is formed with an internal body threading; the body threading and the head threading are each configured to threadingly engage the external shank threading; and in an assembled, fastened position, the head component is held to the body component via interlocking of the head and body fastening arrangements, and the fastener shank extends through the head hole and into the body hole, with the fastener head abutting the first head surface and the shank threading engaging the body threading. 
         [0008]    Even though a fastening arrangement formed on head and body components may be configured to hold the head and body components together in an upright orientation, even without a fastener, in a non-upright orientation the head component and/or the fastener may be prone to unintentionally falling. In such situation a head fastener retention arrangement (e.g. a head threading) can prevent unintentional falling of the fastener. One possible advantage of a head fastener retention arrangement is that a user does not need to be concerned the fastener can fall, and can use one hand to ensure the head component does not fall and their other hand to disengage the fastener, e.g. unscrew it from the body component, without concern that the fastener may fall during disengagement. 
         [0009]    In accordance with another aspect of the subject matter of the present application, there is provided a machine tool assembly comprising: a head component comprising a head hole formed with a head fastener retention arrangement; a body component comprising a body hole comprising a body fastener retention arrangement; and a fastener configured to secure the head component to the body component via the head hole and the body&#39;s fastener retention arrangement; the head fastener retention arrangement being configured to obstruct removal of the fastener from the head hole with only translational movement of the fastener relative to the head hole, while being configured to allow removal of the fastener from the head hole with combined translational and rotational movement of the fastener relative to the head hole. 
         [0010]    In accordance with yet another aspect of the subject matter of the present application, there is provided a machine tool assembly comprising head and body components and a fastener; the head component comprising a head hole formed with a head fastener retention arrangement; the head component being configured to be attached, using the fastener, to the body component; the fastener comprising a fastener head and a fastener shank extending therefrom; the fastener shank comprising a threaded shank portion distal from the fastener head and a non-threaded shank portion adjacent to the fastener head. 
         [0011]    In accordance with another aspect of the subject matter of the present application, there is provided a machine tool assembly comprising head and body components configured to be held to one another via a fastener; the head component comprising a head hole formed with a head fastener retention arrangement. 
         [0012]    Any of the aspects above can be advantageous for one or more of the following reasons: 
         [0000]    a. A user can swiftly remove a head component from a body component, with reduced concern for falling parts (a head component and/or a fastener). It will be understood that a machining process can take into account replacement time, which is related to labor costs.
 
b. A user can more surely remove a head component, without concern of accidental ejection of a fastener from a hole (it will also be understood that it can be difficult to determine a remaining amount of a fastener inside a hole).
 
c. A user can more confidently remove relatively smaller tools. This advantage may be particularly pertinent for, e.g., internal machining applications, or where a fastener is, e.g., a screw of size “M5” (and all the more so for even smaller sizes), since it is harder to hold small components in one&#39;s hand.
 
d. It will be further noted that while known mass produced solutions such as circlips can be cheaply obtained, such may add assembly time and handling of small components can be less user friendly than an integrally formed fastener retention arrangement. The subject matter of the present application can have fewer components than similar constructions utilizing a circlip or like device. Specifically, referring to a connection arrangement of a head and body component, the machine assembly can in total comprise a total three components, namely the head and body components and the fastener. Stated differently, a machine tool assembly can comprise only a single non-integral component (i.e. a fastener) for connecting head and body components.
 
e. A machine tool assembly with both static fastening arrangements (e.g. complimentary integrally formed head and body fastening arrangements) and a dynamic auxiliary fastening arrangement (i.e. a fastener and complimentary construction therefor) can possibly be removed faster than a machine tool assembly with a plurality of (dynamic) fasteners, since each fastener needs to be disengaged from the body component.
 
         [0013]    It will be understood that such advantages may also be applicable to the following method aspects. 
         [0014]    In accordance with still another aspect of the subject matter of the present application, there is provided a method of assembling and disassembling a machine tool assembly according to any of the previous aspects, comprising the following steps: interlocking head and body fastening arrangements; mounting a fastener to a head component by combined rotational and translational movement either before or after step (a); subsequent to steps (a) and (b), engaging a fastener shank to a body hole; and comprising the following disassembly steps: disengaging the fastener shank from the body hole only; and subsequent to step (d), disengaging the head and body fastening arrangements. 
         [0015]    In accordance with yet another aspect of the subject matter of the present application, there is provided a method of disassembling a head component from a body component; the head and body components being fastened together by a fastener extending through a head hole of the head component and into a body hole of the body component; the head hole comprising a head fastener retention arrangement; the method comprising the following steps: (a) withdrawing the fastener from the body hole by combined translational and rotational movement: (b) removing the head component from the body component while the head fastener retention arrangement prevents ejection of the fastener from the head hole by only translational movement of the fastener relative to the head hole. 
         [0016]    It will be understood that the above-said is a summary, and that any of the aspects above may further comprise any of the features described hereinbelow. Specifically, the following features, either alone or in combination, may be applicable to any of the above aspects:
   A. A machine tool assembly can comprise a body component, a head component and a fastener.   B. A fastener can comprise a fastener head and a fastener shank extending therefrom.   C. A fastener can be configured to secure a head component to a body component via a head hole and a body fastener retention arrangement.   D. A fastener head can have a larger circumscribing diameter than a fastener shank (i.e. when measured in a plane perpendicular to a longitudinal axis extending through the fastener shank).   E. A fastener shank can comprise an external arrangement configured to engage a head fastener retention arrangement. The external arrangement can be configured to abut the head fastener retention arrangement (e.g. by the external arrangement having a circumscribed circle of radius greater than a radius of a head fastener retention arrangement&#39;s inscribed circle) during only relative translational movement. The external arrangement can be configured to bypass the head fastener retention arrangement during relative translational and at least some rotational movement.   F. An external arrangement can be an external shank threading. The shank threading can be configured to threadingly engage a threading on a body component. The shank threading can be configured to threadingly engage a head fastener retention arrangement (e.g. an internal head threading). The shank threading can be configured to engage the body threading and the head threading.   G. A fastener shank can comprise a first shank portion and a second shank portion extending between the first shank portion and a fastener head. The second shank portion can have a circumscribed circle smaller than an inscribed circle of a head fastener retention arrangement. The second shank portion can be devoid of an external arrangement configured to engage a head fastener retention arrangement (e.g. it can be devoid of threading). Stated differently, an external arrangement (e.g. a shank threading) can be formed on only the first shank portion, and the second shank portion can be devoid of such external arrangement. One possible advantage of such arrangement can be translational movement of a fastener during assembly (discussed below in connection with  FIGS. 5B and 5C ). Another possible advantage can be a reduced number of rotations needed for, e.g., removing a fastener from a head component.   H. A second shank portion can be longer than a head hole. A second shank portion can be longer than a first shank portion.   I. A body component can comprise a first body surface. The body component can be elongated. The body component can comprise a second body surface located at an opposing side of the body component from the first body surface, and one or more peripheral surfaces extending between the first and second body surfaces.   J. A body component can comprise a body fastening arrangement formed on a first body surface. Stated differently the body fastening arrangement can be integrally formed on the first body surface.   K. A body component can comprise a body hole opening out to the first body surface.   L. A body hole can comprise a body fastener retention arrangement. The body fastener retention arrangement can be an internal body threading formed in the body hole.   M. A first body surface can form an acute internal angle β with a body hole axis of a body hole, as follows: 20°≦β≦60°. It will be understood that a component which comprises an acute internal angle between two elements will also comprise a corresponding obtuse internal angle wherein the sum of the acute and obtuse angles will be 180°. Accordingly, in the present application, references are only to the acute internal angles of the complimentary angles.   N. A head component can comprise first and second head surfaces. The first and second head surfaces can be adjacent surfaces, i.e. sharing a common edge.   O. A first head surface can be formed with an insert seating arrangement. The insert seating arrangement can be configured for receiving a removable cutting insert (e.g. the insert seating arrangement can be formed with a threaded hole or lever hole).   P. A second head surface can form an acute internal angle α with a head hole axis of a head hole, as follows: 20°≦α≦60°.   Q. A head component can comprise a head fastener retention arrangement formed in a head hole. The head fastener retention arrangement can be configured to obstruct removal of a fastener from the head hole with only translational movement of the fastener relative to the head hole, while being configured to allow removal of the fastener from the head hole with combined translational and rotational movement of the fastener relative to the head hole.   R. A head component can comprise a head fastening arrangement formed on a second head surface. Stated differently the head fastening arrangement can be integrally formed on the second head surface. The head fastening arrangement can be configured to interlock with a body fastening arrangement.   S. A head component can comprise a head hole.   T. A head hole can open out at a first head hole end to a first head surface and at a second head hole end to a second head surface.   U. A head hole can comprise a head hole inner surface. The head hole inner surface can further comprise a cylindrical head hole portion and a tapered head hole portion. The cylindrical head hole portion can be adjacent to a second head surface and the tapered head hole portion can be adjacent to a first head surface.   V. A head hole can be formed with a head fastener retention arrangement. The head fastener retention arrangement can be an internal head threading. More precisely, a head hole inner surface can be formed with the head fastener retention arrangement. Even more precisely, the head fastener retention arrangement can be formed on a cylindrical head hole portion of the head hole inner surface. Still more precisely, the head fastener retention arrangement can be formed on the cylindrical head hole portion at a portion thereof adjacent to a tapered head hole portion of the head hole inner surface.   W. A head threading can extend circumferentially around a head hole less than the body threading extends circumferentially around the body hole. The head threading can preferably extend less than three revolutions around the head hole. The head threading can even extend less than one revolution around the head hole. It will be understood that even a small head fastener retention arrangement can provide a retention function, and that with a comparatively small circumferential extension a fastener can be more quickly released when desired. For example a head fastener retention arrangement can extend less than one revolution around a head hole.   X. A head threading can extend an axial extent through a head hole less than an axial extent of a body threading through a body hole. It will be understood that even a small head fastener retention arrangement can provide a retention function, whereas a larger retention arrangement (e.g. the body threading) may be required for providing a fastening force for head and body components.   Y. In an assembled, fastened position, a head component can be held to a body component via interlocking of head and body fastening arrangements, and a fastener shank can extend through a head hole and into a body hole, with a fastener head abutting a first head surface and a shank threading engaging a body threading.   Z. A machine tool assembly can comprise only a single fastener configured for connecting head and body components. It will be understood that a possible advantage of which is that swifter removal of a head component can be achieved if only one fastener has to be unfastened, compared with an assembly with a plurality of fasteners. It will also be understood that a single fastener referred to here is a separate element from the head and body components and hence such machine tool assembly can also comprise integrally formed fastener arrangements in addition to the single fastener.   AA. Head and body components can be interlocked via head and body fastening arrangements. The interlocking can be via sliding movement of a first body surface relative to a second head surface (i.e. requiring at least some movement parallel to the first body surface and second head surface).   BB. A head component can be made of metal. A head component can made of a harder material than a fastener. It will be understood that the subject matter of the present application can provide a particular advantage for machine assembly head component materials (typically steel) which on the one hand provides an advantage to pre-forming a head fastener retention arrangement due to the hardness/solid structure of the material (e.g. steel) and on the other hand enables a fastener to be retained or removed when desired.   CC. Mounting a fastener to a head component can be by combined rotational and translational movement. The mounting can be either before or after interlocking head and body fastening arrangements. Subsequent to the mounting, shank threading and body threading can be engaged.   DD. In an assembled, fastened position, the only contacting portions of head and body components can be a first body surface and second head surface.   EE. In an assembled, fastened position, the only contacting portions of a head component and a fastener can be a fastener head and a first head surface.   FF. In an assembled, fastened position, the only contacting portions of a body component and a fastener can be an external arrangement of the fastener (e.g. an external threading formed on the shank thereof) and a body fastener retention arrangement (e.g. an internal body threading).   GG. The shank threading can be configured with a length that, when the fastener is fastened to the body threading, the shank threading does not contact the head threading. Stated differently, in an assembled, fastened position, the shank threading can contact only the body threading.   HH. When disassembling a machine tool assembly, shank threading can be disengaged from body threading only (e.g. without removing a fastener from a head component&#39;s fastener retention arrangement). Subsequent to disengaging the shank threading from the body threading, head and body fastening arrangements can then be disengaged. The disengagement can comprise a sliding movement of the first body surface relative to the second head surface. The disengagement can also comprise a translational movement, after the sliding movement, of the first body surface relative to the second head surface in a direction parallel with a body hole axis of the body hole. The translational movement can distance head and body components from each other.   II. When a shank threading is formed on only a first shank portion and a second shank portion is devoid of threading; removing a fastener from a head component can be by moving the fastener along a head hole together with a rotational movement.   JJ. After mounting a fastener to a head component and before interlocking head and body fastening arrangements, a fastener&#39;s shank can be abutted against the first body surface, moving the fastener in a head hole towards a first head hole end. The shank can be abutted against the first body surface until engagement of a fastener threading against a head threading halts movement of the fastener relative to the head hole.   
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0053]    For a better understanding of the subject matter of the present application, and to show how the same may be carried out in practice, reference will now be made to the accompanying drawings, in which: 
           [0054]      FIG. 1  is a perspective view of a machine tool assembly in accordance with the subject matter of the present application; 
           [0055]      FIG. 2  is a perspective side view of a part of a body component of the tool assembly in  FIG. 1 ; 
           [0056]      FIG. 3  is a rear perspective view of a head component of the tool assembly in  FIG. 1 ; 
           [0057]      FIG. 4A  is a top view of the head component and a part of the body component in  FIGS. 1 to 3 ; 
           [0058]      FIG. 4B  is a cross section view generally corresponding to a plane corresponding to the section line  4 C- 4 C in  FIG. 4A , except that the head component and body component are spaced from each other; 
           [0059]      FIG. 4C  is a cross section view taken along line  4 C- 4 C in  FIG. 4A ; 
           [0060]      FIGS. 5A to 5D  are cross section views generally corresponding to views in  FIGS. 4B and 4C , and further including the fastener of the tool assembly in  FIG. 1 ;  FIGS. 5A to 5D  are in different operational positions, more specifically: 
           [0061]      FIG. 5A  shows a first position in which the fastener is mounted to the head component and they are spaced apart from the body component; 
           [0062]      FIG. 5B  shows a second position in which only the fastener contacts the body component; 
           [0063]      FIG. 5C  shows a third position in which the head and body components are in an assembled, non-fastened position (i.e. the head and body components are assembled in that they are contacting each other in a position that will be used for machining; however they are not fastened to each other via the fastener); and 
           [0064]      FIG. 5D  shows a fourth position in which the head and body components in an assembled, fastened position, corresponding to the position in  FIG. 5C  except with the fastener fastening the head component to the body component. 
       
    
    
     DETAILED DESCRIPTION 
       [0065]    Reference is made to  FIGS. 1 to 3 , which illustrate a machine tool assembly  10  comprising a body component  12 , head component  14  and fastener  16 . 
         [0066]    The body component  12  can be elongated along a longitudinally extending body component axis A L . The body component  12  can comprise a first body surface  18 A, a second body surface  18 B located at an opposing side of the body component  12  from the first body surface  18 A, and first, second, third and fourth body peripheral surfaces  18 C,  18 D,  18 E,  18 F extending therebetween (the first body peripheral surface  18 C is best shown in  FIG. 4B  and the fourth body peripheral surface  18 F is best shown in  FIG. 4A ). 
         [0067]    The first body surface  18 A can comprise a body fastening arrangement  20  formed thereon. For example, the body fastening arrangement  20  can comprise body dovetail surfaces (e.g. first, second and third body dovetail surfaces  20 A,  20 B,  20 C), each of which can form an acute external angle with a body central portion  20 D of the first body surface  18 A. 
         [0068]    Referring also to  FIG. 4B , the body component  12  can further comprise a body hole  22  opening out at a first end  24 A to the first body surface  18 A, and, more precisely, to the body central portion  20 D. 
         [0069]    The body hole  22  can open out at a second end  24 B to the first body peripheral surface  18 C. 
         [0070]    The first body surface  18 A and first body peripheral surface  18 C can be adjacent surfaces sharing a body edge  26 . 
         [0071]    The first body surface  18 A can be formed with a plurality of body abutment surfaces (e.g. first, second, third and fourth body abutment surfaces  28 A,  28 B,  28 C,  28 D). The body abutment surfaces  28 A,  28 B,  28 C,  28 D can be located along the periphery of the first body surface  18 A. More precisely, they can be located at the corners of the first body surface  18 A. The body abutment surfaces  28 A,  28 B,  28 C,  28 D can be separated by body recessed portions of the first body surface  18 A (e.g. first, second, third and fourth body recessed portions  30 A,  30 B,  30 C,  30 D). 
         [0072]    The body hole  22  comprises a body hole inner surface  24 C. The body hole  22 , and more precisely the body hole inner surface  24 C, can be formed with a body fastener retention arrangement  32  in the form of an internal body threading. 
         [0073]    A body axis A B  can extend through the center of the body hole  22 . 
         [0074]    The first body surface  18 A can form an acute internal angle β of 40° with the body hole axis A B . 
         [0075]    The body fastener retention arrangement  32  can extend several times around the circumference of the body hole  22 . For example, six ridges  34  are shown on one side of the body hole  22 . Accordingly, in this example the body fastener retention arrangement  32  extends about six revolutions around the body hole  22 . 
         [0076]    Referring also to  FIG. 4C , the body fastener retention arrangement  32  also extends a body axial extent E B , measurable parallel with the body axis A B . 
         [0077]    Referring now to  FIGS. 1 ,  3 ,  4 A and  4 B, the head component  14  can comprise a first head surface  36 A and a second head surface  36 B. The first head surface  36 A and a second head surface  36 B can be adjacent surfaces sharing a head edge  38 . The head component  14  can further comprise a third head surface  36 C opposing the first head surface  36 A, and opposing first and second head peripheral surfaces  36 D,  36 E which extend between the first head surface  36 A and third head surface  36 C. 
         [0078]    The first head surface  36 A can be formed with an insert seating arrangement  40 . The insert seating can be configured for receiving a removable cutting insert (not shown). 
         [0079]    The head component  14  can further comprise a head hole  42  opening out at a first end  44 A to the first head surface  36 A. The head hole  42  can open out at a second end  44 B to the second head surface  36 B. 
         [0080]    A head hole axis A H  can extend through the center of the head hole  42 . When the head component  14  is mounted on the body component  12 , the head and body axes A H , A B  can be coaxial (for illustrative purposes only, the position of the body and head components  12 ,  14  in  FIG. 4   b  were arbitrarily shown in positions where the head and body axes A H , A B  are coaxial). 
         [0081]    The second head surface  36 B can form an acute internal angle α of 40° with the head hole axis A H . 
         [0082]    Drawing attention to  FIG. 3 , the second head surface  36 B can comprise a head fastening arrangement  46  formed thereon. For example, the head fastening arrangement  46  can comprise head dovetail surfaces (e.g. first, second and third head dovetail surfaces  46 A,  46 B,  46 C), each of which can form an acute external angle with the second head surface  36 B. 
         [0083]    When the head component  14  is mounted on the body component  12 , the second head surface  36 B, can contact the body abutment surfaces  28 A,  28 B,  28 C,  28 D. Additionally, the complimentary body and head dovetail surfaces  20 ,  46  can interlock to hold the body and head components  12 ,  14  together. 
         [0084]    Referring to  FIG. 4C , the head hole  42  comprises a head hole inner surface  48 . 
         [0085]    The head hole inner surface  48  can further comprise a cylindrical head hole portion  48 A adjacent to the second head surface  36 B and a tapered head hole portion  48 B adjacent to the first head surface  36 A. 
         [0086]    The head hole  42 , and more precisely the head hole inner surface  48 , can be formed with a head fastener retention arrangement  50  in the form of an internal head threading. More precisely, the head fastener retention arrangement  50  can be formed on the cylindrical head hole portion  48 A. Even more precisely, the head fastener retention arrangement  50  can be formed on the cylindrical head hole portion  48 A at a portion thereof adjacent to the tapered head hole portion  48 B. 
         [0087]    The head fastener retention arrangement  50  can extend several times around the circumference of the head hole  42 . For example, two ridges  52  are shown on one side of the head hole  42 . Accordingly, in this example the head fastener retention arrangement  50  extends about two revolutions around the head hole  42 . 
         [0088]    The head fastener retention arrangement  50  also extends a head axial extent E H , measurable parallel with the head axis A H . 
         [0089]    Referring to  FIGS. 4A and 4B , it is further shown that the head fastener retention arrangement  50  has a head fastener retention radius R 1 , which is smaller than a head hole radius R 2  of the head hole  42  (more precisely, the head hole radius R 2  can be considered the radius of the head hole inner surface  48 , and even more precisely can be considered the radius of the cylindrical head hole portion  48 A). It will be understood that the head fastener retention radius R 1  defines an inscribed circle of the head fastener retention arrangement  50 . 
         [0090]    Referring to  FIG. 5A , the fastener  16  can comprise a fastener head  54 A and a fastener shank  54 B extending therefrom. 
         [0091]    The fastener  16  can be elongated. 
         [0092]    A fastener axis A F  can extend through the center of the fastener  16 . More precisely, the fastener axis A F  can extend through the center of the fastener shank  54 B. 
         [0093]    The fastener head  54 A can comprise a tool receiving recess  56  configured for receiving a tool (not shown, e.g. a screw driver) to allow the fastener  16  to be rotated thereby. 
         [0094]    The fastener head  54 A can have a tapered shape. More precisely, a fastener head outer surface  58  can have a corresponding tapered shape to the tapered head hole portion  48 B. More precisely the fastener head  54 A reduces in diameter with increasing proximity to the fastener shank  54 B. 
         [0095]    The fastener shank  54 B can comprise a first shank portion  60 A and a second shank portion  60 B extending between the first shank portion  60 A and the fastener head  54 A. 
         [0096]    The first shank portion  60 A has an axial length L 1 , measurable parallel with the fastener axis A F . 
         [0097]    The second shank portion  60 B has an axial length L 2 , measurable parallel with the fastener axis A F . 
         [0098]    The axial length L 2  can be longer than the axial length L 1 . 
         [0099]    The fastener shank  54 B is longer than the head hole  42 . 
         [0100]    The axial length L 2  can, by itself, even be longer than the head hole  42 . 
         [0101]    The fastener shank  54 B can comprise an external arrangement  62 , e.g. in the form of an external shank threading. More precisely, the external arrangement  62  can be formed on only the first shank portion  60 A. 
         [0102]    The second shank portion  60 B can have a radius, schematically shown designated as R 3 . 
         [0103]    The first shank portion  60 A, not considering the external arrangement  62 , also has a similar radius R 3 . 
         [0104]    The external arrangement  62  has an outermost radius R 4  (e.g. measurable from the fastener axis A F  to a fastener ridge  64 ) which is larger than the head fastener retention radius R 1 . 
         [0105]    Accordingly, the fastener  16  cannot be removed from the head hole  42  by translational movement only but requires rotational movement for the fastener ridges  64  to bypass the head fastener retention arrangement  50 . 
         [0106]    Referring to  FIGS. 5A to 5D , assembly and disassembly of the machine tool assembly  10  will be described. 
         [0107]    In  FIG. 5A , a first position is shown with the fastener  16  mounted to the head component  14 , both of which are spaced apart from the body component  16 . More precisely the tapered head hole portion  48 B and fastener head outer surface  58  are in contact. Since the fastener  16 , on both sides of the second shank portion  60  which extends through the head hole  42 , has a larger diameter than the head hole  42 , the fastener  16  cannot be removed from the head hole  42  in either direction with only translational movement (shown schematically by arrows D T1 , D T2  which are parallel with the head hole axis A H ). 
         [0108]    However, the fastener  16  can be removed, if desired, from the head hole  42  if moved in the direction of arrow D T1  together with a rotational movement about head hole axis A H  upon contact between the external arrangement  62  and head fastener retention arrangement  50 . 
         [0109]    In  FIG. 5B , a second position is shown where a bottom corner  66  abuts the first body surface  18 A moving the fastener  16  in the direction of arrow D T1  (such movement being arrested by contact of the external arrangement  62  and head fastener retention arrangement  50 ). 
         [0110]    It is noted that the fastener  16  is not directly inserted into the body hole  22  since the complementary body and head dovetail surfaces  20 ,  46  ( FIGS. 2 and 3 ) require some sliding motion to be interlocked. Accordingly, the second shank portion  60 B being configured to allow sliding motion within the head hole  42  can facilitate swift assembly of the machine tool assembly  10 . The head component  14  is then moved in the direction of arrow D T3  (i.e. parallel to the first body surface  18 A and second head surface  36 B) until the fastener shank  54 B enters the head hole  42  and the body and head dovetail surfaces  20 ,  46  interlock as shown in  FIG. 5C . 
         [0111]    The fastener  16  can then be rotated until reaching the assembled, fastened position shown in  FIG. 5D . 
         [0112]    To remove the head component  14  from the body component  16 , the above described steps can be carried out in reverse order. 
         [0113]    The description above includes an exemplary embodiment and details, and does not exclude non-exemplified embodiments and details from the claim scope of the present application.