Key Knife’s newest retrofit chipping systems for whole log and waste-wood drum chippers utilize the latest in indexable knife technology.  If you are looking for a dependable and economical chipper system to improve chip quality and increase production, then Key Knife’s retrofit drum chipper systems are the solution. Drum Chipper Advantages Increase Production Improve Chip Quality Reduce Operating Costs Safety Configurations Cassette Holder Holder (for shallow pocket drum chippers) Drum Chipper System Features  PDF brochure download   Adobe Reader is required to view PDF files. You may download a free copy of it from the Adobe Reader website if you do not have it.