The present invention relates to medical and veterinarian rotary tools. In particular, the present invention relates to a rotary tool for the taking of biopsies and drilling into tissues such as nail and bone. More particularly, the present invention relates to nail care devices and procedures to improve the condition of nails, especially relating to the treatment of fungal infections. Onychomycosis is a fungal infection that causes the toenails and/or fingernails to thicken, discolour, and split. The prevalence of onychomycosis in the United States population as a whole is 13%, onychomycosis being more prevalent in the elderly (60%). Onychomycosis can result in permanent nail deformity. The disease can have a significant impact on a patient's quality of life arising from psychosocial issues e.g., due to concern regarding the appearance of one's toenails and fingernails, limiting a choice of sandals or shoes, on the one hand and pain associated with wearing shoes, walking and sports activities on the other hand. The present invention seeks to provide an improved mechanical system for use in the treatment of onychomycosis and other nail bed conditions, and other animal keratin, bone and cartilaginous conditions.