Vacuum fitting adapter for bench dog holes

A workholding system comprising:

• a worktop having a bench dog hole;
• a vacuum fitting adapter configured for installation in the bench dog hole, the vacuum fitting adapter comprising a cylindrical adapter body sized to be inserted into the bench dog hole, the cylindrical adapter body having a through hole traversing from a top end to a bottom end thereof, the bottom end including a vacuum connection port, a vacuum coupling attached to the vacuum connection port and configured for connection to a vacuum source, at least one sealing element on the adapter body operative to reduce fluid leakage between the adapter body and the bench dog hole and to create a friction fit therebetween, and a retention mechanism fixed with the cylindrical adapter body and configured to press outwardly against an interior wall of the bench dog hole to enhance retention of the adapter body, wherein the retention mechanism includes a cap configured to expand the at least one sealing element radially outward to contact an interior sidewall of the bench dog hole;
• and
• an elastomeric vacuum seal positioned on a top surface of the worktop around the bench dog hole to provide a vacuum seal between the worktop and a workpiece.

A method of installing a vacuum fitting adapter in a bench dog hole of a worktop, the method comprising:

• providing a vacuum fitting adapter comprising a cylindrical adapter body sized to be inserted into the bench dog hole, the cylindrical adapter body having a through hole traversing from a top end to a bottom end thereof, the bottom end including a vacuum connection port, a vacuum coupling attached to the vacuum connection port and configured for connection to a vacuum source, at least one sealing element on the adapter body operative to reduce fluid leakage between the adapter body and the bench dog hole and to create a friction fit therebetween, a retention mechanism fixed with the cylindrical adapter body and configured to press outwardly against an interior wall of the bench dog hole to enhance retention of the adapter body, wherein the retention mechanism includes a cap configured to expand the at least one sealing element radially outward to contact an interior sidewall of the bench dog hole;
• placing the sealing element in a groove on the adapter body;
• placing a sealing element on a top of the adapter body and screwing in the cap with threads thereof passing through a center of the sealing element, screwing the cap until it makes contact with the sealing element without compressing the sealing element;
• screwing the vacuum coupling into threads of the vacuum connection port;
• pushing the assembled vacuum fitting adapter into the bench dog hole from a top of the worktop, with the sealing elements causing a friction fit as they are compressed against interior walls of the bench dog hole;
• adjusting the cap to compress the sealing element radially outward to contact the interior walls of the bench dog hole and secure the vacuum fitting adapter into the bench dog hole;
• and
• connecting the vacuum source to the vacuum coupling to provide vacuum to the worktop.