I have very thick chipboard that I use for books and this cut through it with no problems. I was amazed. It did take 2-3 passes on the trimmer, but it cut it clean. The trimmer locks down onto your paper/chipboard and it will not move as you cut. Best trimmer I have found to cut thick items.
After purchasing several different cutters to cut chipboard, this was the only one that really did the trick - the cut is smooth and clean. I WAS using the Fiskars Procision rotary cutter but the cutter folds at the 5.5 - 6 inch mark and it was difficult to get a good cut at 5.5, 5.75 and 6 (the Cal Brand is 12 inches across with no folds). Chipboard also moved in the Fiskar cutter. The only negatives with the Carl Brand cutter are the lack of markings and difficulty cutting anything narrower than 3 inches. There are no 16th inch markings and only the inch and half inch marking go all the way up and down the cutter so if you are cutting an 8.25 by 8.25 chipboard piece you will be able to line it up on the bottom of the cutter but no where else. Huge flaw! Also there is a bar that holds the chipboard down making it easy to cut but that same bar makes it difficult to cut anything thinner than 3 inches.
I almost bought this model because I'm tired of buying $30 trimmers twice a year (I have 5 now) and just couldn't face paying for this Carl trimmer although I came close. Have a look at the new Carl 13715 Trimgear Industrial Trimmer. It's more compact (the second 6 inches slides under the first 6 for portability) and offers most of the features of this model for virtually less than half the price at some places ($93). It cuts all matter of material (and 5 sheets of cardstock at once), and has a self-sharpening blade that "returns to start" after cutting. It's a tidy little package that's portable.
I'm waiting for mine to arrive tomorrow and can update this review then. Really looking forward to it. After trying 5 trimmers, I'm looking for one that will last for awhile.
I love this trimmer! It cuts through chipboard and multiple sheets of cardtock like butter. I make a lot of books with my zutter so this saves me so much time and was worth the price (which I was worried about).