Hole Saw Modification
Mate Alan wanted fit some new flush handles to a folding bathroom door. These required a large hole cutting in the door and a hole saw seemed ideal for the job. He had inherited a hole saw mandrel but it was manually rotated using a tommy bar. “Can you make it work with a drill?” he asked.
The mandrel was hacksawed into two parts near to the handle end.
The shank then needed reducing to 12mm so that it would fit into a drill chuck. Because I only have a small lathe chuck I had to tighten on the screwthreads which was not ideal and did not give a lot of support. The supplement this, I centre drilled the end and supported the mandrel from the end with a half centre. I then faced and turned the rod. There was some damage to the threads so I used a trianglar file to repair them. A better approach might have been to use some softjaws or it might have been possible to turn it between centres as it had a hole in the threaded end.
It’s not my neatest of jobs but it should be accurate enough to drill the required hole.




Metal sculpture in brass, mounted on an 1800s French Coin




