Hi there
Depending on how complex the grip is you should be able to make them with just a file, a small saw, a drill and some sand paper.
I occasionally make wood grips for my umarex 1911 which is quite a simple design so it doesn't take long or require any special tools.
If you can post any pics it would give me an idea about what sort of tools you might need for your project.
Regards
Yusuf