One of the men brushed him aside and pulled at the inset handle.
As well, I think, have had a portrait of Mr. Mills, with Mr. Boon inset.
At the other end of the arc of the inset he can read the degrees of the angle.
A special tool for cutting the inset is desirable but not necessary.
The only parallel to them is to be found in the inset story of Cupid and Psyche.