Notches and Seam Lines

Walking the Seams with Crotch and Inseam Editing

What are notches?

Notes are pattern markings indicating positions that need to match when the garment is constructed.

Part of a 1950s Simplicity pattern guide sheet. The Easy Way to Good Dressmaking explaining various pattern markings. Prior to printed patterns, these pattern markings were cut into the paper tissue.

Notches are like sign posts helping to guide construction.

Assumptions

When constructing the garment we assume that seams that are stitched together should match in length without any fabric strain.

Depending on the design, it is also possible that the draft may have adjusted the seam line lengths so that one seam is stretched or eased to match the second seam line. This could be for design purposes (such as a ruffle), or to account for the difference in fabric behavior when the grainlines of a seam are not balanced¹. If the seam lengths are different, this should be noted in the pattern.

Fremantle Inseam Length Comparison

Check the project summary from

Stacey Taylor

on Threadloop which points out a 6 mm/¼ inch difference between the inseam lengths on the Fremantle pants. After I read this I went back and walked the seams on the original pattern to check.

Walking the Seams

Seam lines are a journey between a starting and ending point. Decide on the starting point which for pants construction is probably going to be the hem which is the foundation of the garment architecture

To match the seams we use the stitching lines, not the cut outline of the pattern.

Align the start positions then walk to the destination point, rotating the pattern so the seam lines are exactly on top of each other.

Why did I not notice the seam length difference?

I had not noticed it because the inseams are long, off-bias seams and the pattern has no inseam notch. I started the seam matching the hem and ending at the crotch point. You might notice a discrepancy if the seam was on grain or a short length. However, with long² off bias seams a small discrepancy is readily accommodated without visible fabric strain.

Patterns drafted for industry will have a minimum number of notches but patterns for amateur garment makers will tend to have additional notches because we could benefit from additional guidance. The Fremantle pant does not have the inseam notch that most pant patterns have. If this pattern had such a notch, the discrepancy would have been more readily noticeable.

After

Stacey Taylor

pointed out the discrepancy I looked back at my toile and yep, this explained a minor drag line I was seeing that I had ignored thinking maybe I had put it together too hastily and some inaccuracy had crept in. I couldn’t think of a rationale and it is not considered sufficiently important for it to be mentioned in the instructions so I decided to alter the pattern and make a second toile. So much for a palette cleanser project. I don’t think this is a big deal at all and is probably only noticeable for if you are both (a) a bit fussy³ and (b) making a toile on the small end of the pattern size spectrum.

Pattern Alterations

There are several different ways we could adjust the seam lines to make them match. Each decision has pros and cons. We do not want to adjust the hem because this is on grain and the foundation, so we will adjust the top of the inseam.

As we learned with the #OLOlivePants, the crotch seam and inseam work together and alterations to one often require alterations to the other⁴. I am going to leave the front crotch seam untouched and remove the extra length from the back inseam.

This is where the French curve ruler comes in handy! Use the curve to make a smooth curve connecting the new crotch point with the existing crotch seam.

Pattern Alteration Question

The photo below shows two different options for editing the crotch curve, which option would you choose and why?

If you would like a hint, zoom into the photo and look at the tick marks on the ruler. Here is a close up comparison.

If you would like another hint, ask yourself which pattern piece this gets sewn to in order to create a complete crotch seam.

Comment with your thoughts and I’ll post a follow-up explanation tomorrow. Ciao for now!

1. To date we have not discussed ‘balance’ very much because the term is used in a variety of different ways. This it is an important topic we will be addressing in conjunction with our #MPWM projects

2. Inseam length is 69.5 cm/27⅜ inches

3. Polite British speak for “on the OCD spectrum”

4. This might also be a good time to remind readers that there is a misunderstanding about TDCO I frequently see online, some version of the claim “in TDCO you don’t alter the crotch seam”. Every seam line can be altered including the crotch seam. TDCO helps with altering the crotch seam in a manner that does not impact the design.