In 1983 Rotring produced a compass sucker attachment for tracing circles on film and avoid compass tip from making holes on film surface. The section of the sucker stem was 3mm
The rotring universale adapter is #1. On that metal adapter, thre is a threaded insert that comes out, leaving a really large thread diameter...any ideas what could screw into that?
I’m not sure if you’re asking if Kern made a 4mm attachment or if they will receive a 4mm attachment. The answer to both questions is yes. I happen to have a Kern Swiss set that includes a 4mm threaded attachment for tech pens. This same set will of course receive a 4mm shank attachment.
