When you fold cover stocks on a buckle folding machine, you might encounter one problem you don’
t get when running text-weight paper. As you adjust the fold on a light stock, you get instant feedback on whether it’s been adjusted correctly. In other words, as you move the plate’s paper stop you immediately see the result of your adjustment as the next folded piece exits the machine.
When you run a cover stock that’s been creased (scored) your fold plate can be up to 1/8” or more out of position from the score line, yet still fold on the score. 
The photo (above left) shows a text stock purposely folded about 1/8” out of square, yet when we ran a scored cover sheet through the same folder, it managed to fold squarely, right on the score. (photo right)
“So what?” you might ask. “If it’s folding on the score what difference does it make where the fold plate is set?”
You’re partly right in that it might not always make a difference. Yet if you fold enough of this type of work, we’ll wager there will indeed be occasions where quality and production are negatively affected by an improperly set fold plate.
Some symptoms of the problem:
- Paper jams in the fold plate
- Folding slightly off the score (or entirely off) in an intermittent fashion
- Marking or scuffing around the fold
- Bent corners and ‘dog ears’
If you find yourself struggling with such problems on creased cover stocks, whether you are creasing it on the folder or it is pre-creased, take a minute to check that the fold plate stop is positioned correctly.
Grab some light text stock (preferably uncoated) and cut it to the same size as the job you’re running.- Re-set the fold roller calipers with the text stock.
- Run a sheet of the text stock.
- Fold the cover stock by hand. The machine-folded text stock should precisely match the hand-folded cover stock.
If the text stock doesn’t match, adjust the fold as needed until it matches the cover. Then be sure to re-set the roller calipers with your cover stock before you start folding covers again. This simple technique should now prevent any problems caused by the incorrectly set fold plate.
As always we welcome your comments and experiences below!