VICMARC VM120/150 Dovetail Jaws
 
Dovetail Jaws have been designed for mounting bowls by expanding into a recess or clamping onto a spigot.
 
The sizes indicated on the drawing show the Jaw measurements at a perfect circle.  VM120 and VM150 chucks provide approx. 48mm of expansion beyond these specified sizes shown with the exception of the 85mm and 105mm Dovetails (see below). All Dovetail Jaws have an internal dovetail angle of 13 degrees for clamping and an external dovetail angle of 13 degrees for expanding. 
 
The Vicmarc range of Dovetail Jaws also have a machined taper on the face of the dovetail which aids in clamping both on a tenon (clamp mode) and in a recess (expansion mode).  When clamping on a tenon it is often the case that the flat section of the bowl/tenon will be tapered the wrong way slightly or may have wood fibres or debris that can be in the corner of the tenon.  With the jaws being slightly tapered it allows for a firm and accurate hold slightly away from the corner.  This will ensure an accurate hold without wobble.  When clamping in a recess the flat section is often tapered towards the centre of the bowl.  This taper allows for a firm hold right in the corner (outermost diameter) which will ensure an accurate hold.
 
There are 7 options. (see images)
Description              Dim A        Dim B        Dim C        Part No.
Dovetail 85mm             63mm        85mm       12mm          V00675
Dovetail 105mm           84mm      105mm      12mm           V00676
Dovetail 128mm          106mm     128mm       14mm          V00677
Dovetail 148mm          126mm     148mm       14mm          V00678
Dovetail 173mm          150mm     173mm        16mm          V00679
Dovetail 198mm          175mm     198mm        16mm          V00680
Dovetail 223mm          200mm     223mm        18mm          V00682