Reverse Engineered Field Pants


Over the past three weeks or so, I’ve been slowly picking my way through a reverse engineering of a favorite pair of pants. These military surplus pants finally died this year, after many adventures, and were some of my favorite pants yet. What I thought was going to be an easy tear apart and copy, turned into an involved project that took quite a while longer than expected. 


These are the originals, a pair of Propper-brand military cargo pants. These are some of the better fitting pants I’ve owned, but were not made with longevity in mind, which is to be expected for $35. After struggling to draft a well fitting pants pattern myself, I thought it would be easy to take these apart and copy them. In reality, the project was pretty difficult and took a lot of effort and drafting time.


To start off, I grabbed a fresh razor blade, my seam ripper, and started de-constructing. I saved as much as I could from the originals, including all the buttons I would need for the new pair. Taking apart a pair of pants is tedious work, so I only removed one half of the pair for drafting, and saved the other half as a reminder for construction technique.

fullsizeoutput_470Here are the pieces I used to make my pattern.

There were many different seam allowances used on the originals. Some were as small as 1/4 inches, while others were up to 1 inch. The two halves of the inseam and side seam had widely different seam allowances, I’m guessing to account for an industrial flat felling machine. I averaged the side / inseams to 5/8ths so I could do the homemade flat felled seam.



The fabric I chose is a ripstop, 50% cotton, 50% nylon in olive drab. The cotton should help breath, while the nylon will enhance drying times. I think these will make for a good warm weather pant where full synthetic materials are not required.


Something is not quite right with the grain line in the picture above. The backs seem to be way skewed. I’ll need to re-visit this for future makes. (A lot of this was done late at night, so I might not have been thinking straight)


After cutting, I like to serge everything that needs it, all in one go. This includes all side seams, pocket bag side seams, fly and fly covers.

The main pieces were easy to copy, but once I got into the smaller details, things got more complicated. I needed to replicate the technique used for the back pockets, which included a single welt pocket with a flap that included hidden button holes. I originally thought to skip the hidden button holes for simplicity, but changed my mind when I realized they were there to prevent hang ups when scooting around logs and such.

I am using the self fabric for my pocket bags, and integrated the welt into the bags for simplicity. I also omitted a facing, as everything is the same color. This also helps to reduce bulk. fullsizeoutput_476

The hidden button holes required some trial and error to figure out the construction technique. The button holed piece needs to be placed inside the main flap fabric, sewn along the ends, and turned.




One of my goals for the pockets was to French seam the entire pocket bag, and not have any serging or loose ends. I really like it when the inside of a garment looks just as neat and clean as the outside.


Above is the finished pocket bag, which I was quite happy with.

Flap detail

Please ignore the sloppy topstitching, again done late at night. In the future, I need to topstitch through the pocket flap as well, to keep everything laid down tight.

After finishing the back pockets, I moved on to front fly closure. These pants are a button fly, and I’m not great at that technique yet. The fly came together good enough, but has a couple of issues. Something didn’t come together quite right when felling the main seam, and I needed an extra barrack to tidy everything up.

Once the fly closure was put together, albeit not as neat as I would like, the rest of the pants went together quickly. The final seams were put together, and the waist band added. fullsizeoutput_47f

The pants are not without their issues, but they’re good enough for me. I’ll make some adjustments to the pattern and the construction technique for future makes. I’ll probably make a chino type pant for day to day wear, and possibly a camouflage version for hunting.



5 thoughts on “Reverse Engineered Field Pants

  1. Your new pants look amazing! The details make all the difference! Drafting the pattern and getting all those seam allowances was a full time job!!! I do love the pockets and how they are super neat, yes inside and out! And your top stitching is better than I see on any RTW (ready to wear) pants! And finally the fit is perfect! You reversed the heck out of these pants! Well done! 🙂

    And now that you done all that hard work you have the added benefit of having a pattern for any type of fabric or color you choose! Custom made, well fitting and well designed items are hard to come by these days. But then again, I guess that’s what we sew! 🙂


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