Applying a clean and sharp ink circle to aid locating valves on a slide is made easy by adding a simple flexible arm to a ringing table. The arm can be made of any shape needing just two holes, one for the mounting bolt and the other to take the barrel of the pen. A 3mm hole is perfect for a technical drawing pen which is probably the ideal tool for the job when used with indian ink. Rinse the nib through frequently to prevent clogging.

Circles of consistent diameter can be ensured by fitting a stop or block to the rear of the arm.

A screw block will be added to this arm to allow accurate dimensioning which is somewhat hit and miss at present.

I'm still searching for a convenient and foolproof way of applying circles to coverslips and woould love to hear of any suggestions!