Pattern Adjustment on the Fly
Fly front alteration Shop Pant edition
When fitting, I changed the vertical dimensions of the front crotch, how should I adjust the fly?
Here we are talking about changes to the rise extension on the front right pattern:
1. I made it longer
IF you made it longer, the simplest is to just move the rise extension keeping it the original length.
You might wish to make the fly front longer and use a longer zipper, if so read on.
2. I made it shorter
As mentioned in a previous post on shortening the leg, sometimes the opposite adjustment is not as straightforward as simply reversing the steps.
If we shorten the rise, we cannot use the original rise extension because, for construction reasons, that is restricted to the straight line portion of the crotch seam.
We now need to change three pattern pieces, the rise extension on the front right, fly extension and fly front:
These pattern pieces need to match up precisely for smooth construction (more on the fly installation instructions later).
As readers will know, I am a big fan of using what the pattern has provided before going off piste.
The Shop Pant pattern provides four length options:
The easiest adjustment is to choose a smaller (or longer) fly front from one of these options. Alter the front rise extension to match the selected size range and use the corresponding fly front and fly extension pattern pieces with no change.
Zipper length versus fly front length
The zipper length measures the zipper teeth only. This does includes the stops but not the zipper tape end.
The fly front length reflects the J stitching of the construction from waistband to crotch seam; this will be longer than the zipper.
Which brings us to a related question, what is the best length for a fly front?
Read on for more and I promise we’ll get back to pattern adjustments if you want to use a zipper shorter than 6 inches/15cm.
