In turning on a centre lathe between running centres an axial force is necessary to hold the workpiece steady under the forces generated in removing the material. This force can generate substantial friction moments at the interfaces between the supporting centres and the workpiece which oppose bending out of the line of the centres. The effect of this is found to cause some reduction in errors of form and out of roundness predicted without including friction. It is shown that the variation in quasi-static and cyclic compliance as the tool traverses the work is non-linear and sudden changes occur which can trigger chatter conditions.