How to avoid chatter or Venetian blinds? FAQ Report The specimen might be improperly frozen onto the specimen disc. Remove the specimen; ensure that the disc is clean and that the grooves are cleared of any build up of cryocompound. Remount the specimen on the disc using a minimum amount of cryocompound. The specimen disc is not secured properly. Ensure that the disc is properly inserted into the specimen head. The specimen is very hard, or not homogeneous. Reduce the specimen surface area if necessary; cut at the temperature necessary for the most difficult to freeze component of the tissue; if possible, trim the block into a V shape and orient the block so that the smallest surface will contact the blade first. Rigorous trimming of the block has caused the specimen to detach from the disc. Re-mount the specimen onto the disc. The blade is not clamped properly. Check the clamping. It may be overtightened. (Position the locking lever so it is in the same plane as the disposable blade front plate.) The cutting edge is dull. Use different parts of the cutting edge or replace the blade. The knife profile is inappropriate for the specimen to be cut. Use knife with different profile that can withstand the cutting force. The clearance angle is incorrect. Set correct angle. Cutting speed is too fast and should be slowed down.