Before My Sloper was born, we designed and graded our patterns using a commercial software package. This package generates PDF patterns that have margins along the border. Assembling these patterns are not hard as long as the printed pages and the margins align. Here is a tutorial that shows you how to align these printed pages.
When you print your PDF pattern, you need to configure your printer settings to “No Scaling” or “Actual Size” depending on your printer. Here are a couple of snapshots of configurations based on different PDF viewers.