We made several improvements when we designed the QC2. First the cutting guide head is made of ABS where the QC1 was made of Acetyl. ABS is much tougher and essentially unbreakable where the original QC1 plastic was somewhat brittle and could break when dropped.
The QC1 'gripped" the rail system with two tabs on either side of the cutting guide head. The QC2 has a "wiper" that makes contact the entire width of the cutting guide head for more even, smooth, stable and secure contact.
We added a bunch more angles to the QC2. It also has a button you push to release and change angles where the QC1 you had to fight the spring a bit to articulate the cutting guide.
The QC2 has a new metal stamped Speed Gauge which is longer and more accurate than the original plastic version.
We also changed the Clamp Bar so it will raise slightly higher making it easier to slip your fabric under it.
The original Quiltcut had a plastic side rail which we had some "tolerance issues" with so we went to an aluminum side rail that is has the exact same dimensions as the clamp so it slides the same on both for overall consistent operation.
We quit producing QC1's in 2002 and I highly suggest anyone interested consider a QC2 over the original given all the improvements.
SSM