A rotary microtome is primarily used for cutting sections of frozen tissue as well as pastes, powders and some food substances. This microtome is contained in a refrigerated chamber, at a temperature of which can be maintained at a preset level by cryostat. Since it is difficult to cut very thin sections from soft embedding compounds, the hardness of the embedding compound also matters because it reflects the thickness at which sections can be cut. Animal and human tissues are too soft when fresh to be cut thinly. Some form of pre-treatment is required to harden the tissue to facilitate cutting thin sections. Freezing or embedding tissues in a medium which offers support for cutting. To firm tissues enough for sectioning, they are frozen in a cryomatrix eg. OCT Compound. It operates at temperatures of –40-0ºC and is able to cut sections 0.5-300 μm in thickness. A full rotary microtome action is robust enough to cut even very hard specimens such as decalcified bone.

This automated rotary featured machine of the cryostat prevents injuries associated with repetitive motion. Once the user is comfortable with the use of the cryostat, the automated motor function will be very useful. Using this reduces the amount of wasted space inside the freezing chamber giving quicker cooling and better temperature stability. A coarse adjustment, cutting and anti-roll plate controls are all available outside the freezing chamber. This way, it minimizes the number of times the user must access the freezing chamber in routine operation reducing the build up of frost. The rotary microtome can be setup to take re-useable tungsten carbide blades or disposable blades. Knives made of high quality non corrosive tungsten carbide, practically non magnetic and 100 times harder than hardened tool steel, yet it is breakable because of extreme hardness. These are manufactured from hardened, heat treated stainless steel free from all impurities and containing 12 to 15% chromium. Then latest was added part of a microtome incorporates automatic specimen retraction in the return stroke to protect both the knife and the specimen from possible damage.

Modern blades are disposable and last for around 20 to 30 blocks. Thus made these disposable blades highly in unavailable in the market and large heavy dangerous knives re-sharpened regularly were/are used instead. To achieve fine honing, a diamond paste is applied, containing industrial diamonds of 1 µm or less, to a lapping stick which is then moved against the edge of the knife. For manual honing and stropping a knife bevel must be fitted to the back of the knife to ensure correct angle of bevel for the edge of the knife. The correct angle is also important to reduce friction as the knife edge passes through the block. The clearance angle is that between the knife edge bevel and the block If the angle of bevel (cutting angle) is too great it can cause compression in the cut section. If the angle is too fine the edge of the knife can vibrate causing chatter in the section. A balance between these extremes will provide the best results. Generally the sharper knife will have a finer cutting angle.