The optional Smart-binder trimmer center-knife system may be used to produce book sizes which are less than 160mm (6 1/4") spine length (e.g: A5 landscape or 8 ½ x 5 ½" oblong). Each sheet is printed with 8 pages instead of the normal 4 pages. These sheets are individually folded and then either stitched or glued together in the normal way. The center-knife then splits the resulting book into two smaller sized books, which are delivered in two parallel streams. Center-knives are available in widths of 6.35mm (1/4") (CKN-100) and 9.52mm (3/8") (CKN-101). These trim 6.35mm (1/4") or 9.52mm (3/8") out of the middle of the book. Book thickness is limited to 3mm (1/8") for the 6.35mm (1/4"h) knife and 4.5mm (3/16") for the 9.525mm (3/8") knife. Option CKN-102 can separate the two books without any trim out. Thicker books may be produced if using the CKN-102 single knife center-split instead of a double-edged trim-out knife.	Book A Trimmer center-knife Center trim-out waste (drops onto waste removal conveyor below) Trim-out dimension 1/4" or 3/8" (or thicker by special design) Book B
Images of trimmer center-knife Double book stream on the SB delivery when using the trimmer center-knife Trimmer side knife (LH) Trimmer lower knife (RH) Trimmer side knife (RH) Center knife holder (upper) Trimmer center trim-out knife Extra book drive wheels (needed when center knife trimming)

Important notes:
Installing and using the trimmer center-knife CKN-100, CKN-101 or CKN-102

The CKN-101 knife is supplied with center-holes in the upper knife so that air blow can be connected to assist blowing out the center-strip from between the two blade edges when the knife rises after each cut. These blow holes are not available on the narrower ¼” wide knife CKN-100 so this knife has an increased risk of waste paper build up between the knife blades.

If the CKN-102 single-bladed knife is fitted then only one bed knife should be used. Two bed-knives are needed if the CKN-100 or 101 (gutter cut) knives are fitted. No center trim waste is produced when using the CKN-102.

To install the trimmer center-knife assembly takes about 90 minutes and about 15 minutes is required to subsequently remove the upper center knife in order to stop center-trimming.

When installing the center-knife care must be taken not to turn the machine backwards during movement of the indexing transport belts as this may cause the belt timing to be lost.

WARNING!! Extreme care must be taken when handling any book trimming knife. This must only be done by competent, trained personnel.