I don't mean to discourage you nor rain on your parade. I am a big believer on helping people achieve what they want, even if it seems like I am putting obstacles in your path.

I can tell you that about 20 years ago after quilting for 20 some years, I made a king sized log cabin for my cousin and was able to machine quilt a simple grid to hold it together on my vintage sewing machine. LOL I would not recommend the experience for a newer quilter.

My niece has requested a king sized quilt as a wedding gift -- I am thinking maybe I'd rather buy something expensive! I am much happier at dimensions less than 100".

You can look at some other block size options -- but sometimes Log Cabin quilts are best when square, depending on the overall design you want. If you took that pattern I linked and made a center color with 3 rows each side, it would make a 14.5 inch block, making 8 blocks per row would slightly decrease the size, to 116 instead of 120. Or don't underestimate the value of coordinating fabric borders!

Best of luck whatever you decide to do. Hope you work out your thoughts and plans with us here :)

This will depend on how many fabrics and the width of the strips you plan to use. You can also do this with paper piecing, it should keep your blocks square. I find a king size might take around 13 yds, especially as you have so many seams. You need to have half of light colours, and half dark. If you do not need each block to be identical the pieces can be alternated, otherwise you will need more of some fabrics and less of others.

Thank you for your advice and the helpful links .

To all who have given me advice thank you, as a beginner it is very valuable getting this information. I am so grateful I found this board.

I, too, wanted to make a Log Cabin as my first quilt. (That was about 12 years ago.) Everyone discouraged me from doing it (every quilt shop I visited). i, too had a hard time figuring out how much fabric to buy. I still have some yardage from that quest. I finally ended up making a disappearing 9 patch for my first quilt. I learned a lot on that quilt. Amazingly, it turned out pretty well.

I still have never made a Log Cabin, but your journey reminded me of my early quilting desires.

bkay

The first log cabin I made was a lesson in accurate 1/4 inch seams. And it has been an essential lesson for all my quilting life.

My first log cabin was in a class based on Eleanor burns method. We all kept asking the instructor how it would work. She said trust the process. We all made pretty great quilts.
I have a neutral plain bed covering and make my quilts just big enough to cover the top, no drape and don't cover the pillows. It is manageable for me and can change them out. The neutral covering kind of disappears because the quilt is the focus

Buy Eleanor Burns' Quilt in a Day Log Cabin book. It is wonderful for a beginning quilter. It spells out every single thing you need to know: yardage for each color, even how to stack your pieces as you sew.

I’m a bit late to the party, but maybe take a look at this video: https://youtu.be/JFHzO8yOURI?si=pxGjxbtzJduJDLd1

Later in the video she says it fits her king sized bed and she gives all the fabric requirements for the blocks and shows a great way to piece them. She also shows several layouts.

Actually, it's not that bad if you have a machine with a reasonably large throat space. I just quilted a 108" x 98" quilt for our bed on my Juki 2200 QVP Mini (same as the Juki 2010) and it wasn't bad at all.

I also did a similar size quilt on my old Bernina with a tiny throat space. I used Marti Michell's Quilting in Sections technique to do it. It was work but doable.