Thread Theory

Welcome to the new era of menswear sewing. Go ahead and create something exceptional!

Free Pattern: Download the Arrowsmith Undershirt today!


Some of you observant blog readers noticed that there was a certain v-neck top featuring prominently in our Comox Trunks photoshoot a couple months ago:Blog Edit-1

This top is called the Thetis Tank and will be available in several months through the Sew It All TV show and magazine!  The episode I filmed with the Sew It All team in Golden, Colorado, was all about how to sew this super quick and easy project.

In the meantime, while you eagerly anticipate the magazine issue featuring this v-neck pattern, we have ANOTHER sleeveless top pattern for you to sew in time for summer!

Introducing Thread Theory’s first FREE sewing pattern: The Arrowsmith Undershirt.


This pattern is available as a PDF download for free as a big THANK YOU to all you avid menswear sewers who have supported us and our business over the last year!  As of today, it has been one year since we launched our very first pattern – the PDF version of the Newcastle Cardigan.


This tank is a super quick and easy project that can be sewn using all manner of knits.   The Arrowsmith Undershirt is the perfect sleeveless tank for layering or for hot summer days.  The enlarged armholes and deep crew neck give this shirt a very modern appearance and they also make it really easy to sew without a serger (you could even use a straight stitch if you wanted to because the head and arm openings are large enough that they don’t really need to stretch when the shirt is put on or taken off).  There is an optional patch pocket that can be sewn in a knit or a woven fabric.  The pocket is a great way to add just a little bit of colour and intrigue against a basic background – especially if the recipient isn’t very adventurous with their clothing colour/print choices!


So, please, take our sincere thanks and our free pattern: Head on over to our website to download the Arrowsmith Undershirt and get sewing!  By the way, we’d love to see what you sew!  Add #Arrowsmith to your photos so we can find them and add them to our Pinterest page!

34 thoughts on “Free Pattern: Download the Arrowsmith Undershirt today!

  1. There is a pdf security password, when trying to open the file with photoshop. Any help?

  2. Pingback: Matt’s Grey and Red Arrowsmith | Beansy B.

  3. I was just wondering why the bias for the tank is smaller than the arm hole? This really caused me some problems! I am a beginner, and have been trying to find an easy pattern. Thanks

    • Thanks for trying out our patterns! The bias strips for the armhole and neckline are smaller than the openings because the pattern is designed for knit (stretchy) fabrics. When attaching the bias strip to the openings, it is necessary to stretch the strip slightly as you sew. This will result in an armhole and neckline that is nicely shaped rather than baggy because the bias strip is making the hole in the fabric keep its shape. Generally a knit binding should be approximately 80% shorter than the opening you are sewing it to. I hope this helps you! Please feel free to ask any other questions you might have :). Have you finished your tank now or are you currently working on the binding? I hope you were able to conquer it!

  4. Thank you for this freebie! Between this and the Strathcona t-shirt, it looks like I will have a lot of menswear queued up for the summer! =) Will the Thetis pattern be available outside of the magazine eventually?

    • Yes, you’ll be busy! The Thetis Tank will only be available through Sew It All – I believe they’ll be including the instructions in their magazine and will have the pattern as a download online. I’ll post about it once it’s published so that everyone will know where to find it!

  5. Thank you for this pattern! I think I’d love to make one or more of these undershirts for my boyfriend. I’ll try making them using some of his old tshirts that are stained from deodorants and if I manage well (I have never sewn with knits before) I’ll allow myself to buy fabric to make something a bit more special for him.

  6. Thankyou for this pattern. Do you recommend any fabric for it? I’m a beginner 🙂 x

  7. An excellent pattern – thank you so much….now to find the fabric!

    • Oooh I’m glad you’ll be sewing one of our patterns! I always used to look forward to your projects on The Sew Weekly so I really look forward to seeing what you come up with!

  8. Oh gosh I can just see this on my boyfriend! I can’t wait to make one…or twelve!

  9. Congrats! Thanks for the pattern 🙂

  10. I wish I saw this before I left work!! Need to print, now! I love a good tank. I see many of these in MY future ;o)

  11. If only it wasn’t verging on winter in this end of the world *laments the return of warmth*

    • Ah well, it’ll be waiting for you for next summer and you can enjoy sewing you peacoat in the meantime :). Last May we pleased the southern hemisphere by releasing a cosy cardigan and now it’s time to please the north lol!

  12. Hooray! I’ll be buying up some fabric for some on Monday 😀

  13. Omg! This is what I need for my fiancee! This is great!

  14. Thanks so much! I’ll have to find some time to whip one up for my husband–it’ll be perfect for his summer shirts!

    • It doesn’t take long to sew (maybe 2 hours absolute tops?) – especially if you do them in batches like I have been…It’s been quite the little assembly line in my studio!

  15. Hubby has been asking be to make a tank for him! You are awesome. I’m off to find a fabric so that I can surprise him.

  16. I think my husband is going to love you for this! What an awesome pattern, thank you!!!! xo

What do you think? Leave a comment for me :)

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s