A crimping tool is provided, where the tool comprises a mandrel (1) having a first portion (3) with a first outer diameter, and a second portion (5) with a second outer diameter which is greater than the first outer diameter. A chamfered abutment face (7) is provided between the first and second portions (3,5). At least one first collar (9) is mountable on the first portion (3) of the mandrel (5) and has a chamfered first end (11) which in use abuts the abutment face (7). At least one second collar (13) is mountable on the second portion (5) of the mandrel (1) and has a chamfered second end (15) which in use abuts the first end (11) of the first collar (9). A method of using the tool to form one or more crimps in a piece of fabric is also disclosed.