One of the factors affecting considerably gear cutting accuracy consists in technological basis quality. The largest influence upon treatment accuracy of a reference hole have broach wear and errors in hole grinding. In the paper there are shown the investigation results of technological parameter effect upon broach stability and accuracy in broach treatment and grinding of a reference splined hole. The developed model of a process and a tool test allowed defining optimum parameters from the point of view of the treatment accuracy, surface layer parameters and life of a tool and cutting modes. It was considered simultaneously the hardening impact upon a reference hole surface layer.