E-book for Pattern Cutting

[chuck123wapati]

go to ebay , search 'simplicity back pack pattern" or "simplicity men's clothing pattern". Buy the ones you want, or that are closest to what you want.  Study them, re-design them if needed. Actually, using or at least studying a real pattern will answer tons of your questions.

I learned as a young boy how to sew from watching my mom. She made most of her clothes, as well as quite a few of mine. Those old patterns are where it's at for learning what you need to know; they will coincide with the ebook so you can understand what it is telling you.

[friquant]

On 3/9/2026 at 7:00 AM, Digit said:

Personally I've so far always calculated radii and circumferences for making bags with rounded corners and they always matched up. The important thing (as I see it) is to line up everything correctly by marking specific locations (first on the pattern, then on the leather) and using CA to put the parts together so that they can't stretch/shift while stitching. Since the CA is only for temporary setting, you can use a weaker, water-based CA.

For a 30cm diameter bag with 1.5cm seam allowance, I cut a circle 33cm diameter. Then I cut a rectangle 97.25cm wide.

30 * π + 2 * SA = 94.27 + 3 = 97.25

This was some kind of vinyl with a checked texture on it. Brand name is "Staph Chex". Started stitching around it (no glue) and the rectangle wasn't wide enough. One thing I notice about this material is it has a lot of shear stiffness. Maybe that has something to do with it. I'm going to cut a rectangle 3cm wider and try again. (I know you said glue. I must be a massochist.) I want to find the measurement that allows me to sew them together without glue. Still analyzing my motivations for that..

I've also been trying to convince myself to use almost no top tension when mocking up a pattern for the first time, so if I need to undo it I can pull the bottom thread out with one tug instead of ripping all the stitches. So far I haven't listened. 🤷‍♀️

 

On 3/9/2026 at 7:00 AM, Digit said:

using CA to put the parts together so that they can't stretch/shift while stitching. Since the CA is only for temporary setting, you can use a weaker, water-based CA.

Can you link to an appropriate weaker, water-base CA?

 

On 3/9/2026 at 7:00 AM, Digit said:

When designing a new bag the patterning process is similar: start with an idea, make some sketches, make a mockup out of sturdy, stapled-together paper (such as wallpaper), make a first pattern, assemble something from a cheap material (eg felt) and see how it would fit together, noting the order of assembly and feasibility of (machine) stitching it. Adjust where needed and create a final pattern.
Making a mockup of a bag also gives insights into its final size and proportions, which is difficult to imagine when just sketching or patterning.

Paper stapled mockups sound quite useful! I've done them for other projects but never for sewing or bags.

[Digit]

17 hours ago, friquant said:

Can you link to an appropriate weaker, water-base CA?

I use Ecostick 9015ST; I don't know which stuff we use at school. The degree of bonding depends on the open time; if you need to be able to adjust a bit, stick the pieces together while still wet.

 

17 hours ago, friquant said:

For a 30cm diameter bag with 1.5cm seam allowance, I cut a circle 33cm diameter. Then I cut a rectangle 97.25cm wide.

30 * π + 2 * SA = 94.27 + 3 = 97.25

That seems correct.

Note that leather has a thickness. When laid out flat, 97.25cm would be correct if you'd make the bag out of thin paper and if there is no 'waste' in the material curve on the seam. If you want the side at exactly 30cm diameter, you need 97.25cm on the _inside_ (flesh side) of the barrel; if your leather is, say, 1.5mm thick, the _outside_ (grain side) of the barrel needs to be 95.19 cm (radius = 15cm + 1.5mm). Add to that two quarter circle circumferences with radius 1.5mm (the seam of the barrel can be seen as a circle with radius = leather thickness and centered around the seam thread) and you get to 95.66 cm. Add another 3cm seam allowance and you end up with 98.66 cm which is already 1.41 cm larger than what you have.
If you have more than 1.41cm shortage, then that's probably caused by not stitching at exactly 30cm diameter. Even an error as small as the needle head pricking exactly left or exactly right of the seam line (which I presume you marked on the flesh side) can lead up to several millimeters error along a circumference of 95 cm. If you're using an edge guide the error is likely to be larger even because edge guides aren't very accurate unless you're using very thick and stiff leather.