I often get questions about my carving arm and where to get one. I do not remember the source of mine, but I have found that The Woodcraft Shop has a laminated oak carving arm for sale.
If you are interested in making your own, Woodcarving Illustrated has a Building a Carving Arm article on their site. The article includes detailed plans.
A secure way to hold your work as you carve is key to personal safety. Are you using a carving arm or something similar?