diff --git a/printed-stepper/README.md b/printed-stepper/README.md
index 9bf957ec8597d121cff8a5c127450701470e6f87..2d1399b8dc212bb030c021f9cb0c82eeedbab0cf 100644
--- a/printed-stepper/README.md
+++ b/printed-stepper/README.md
@@ -1,3 +1,9 @@
+## Printed stepper motor
 
+The motor below was printed using <a href='https://www.proto-pasta.com/pages/magnetic-iron-pla'>Proto Pasta's Iron-doped PLA</a>, which has a relative permeability of around 10.
 
-<img src='printed-stepper.jpg' width=300px>
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+<img src='printed-stepper.jpg' width=600px>
+
+This directory contains STLs and a Fusion design file.
+
+Be warned -- there are a few crucial design errors!  First, the tooth size is too small given the reduced relative permeability of this filament, as compared to magnetic steel ($`\mu_r \approx 1000`$).  Second, while the two magnetic poles have a full tooth offset, the two electrical phases don't have a half tooth offset.  Duh!  So, even if the tooth size we correct, the stepper wouldn't step in a predicatble direction.  Someday I'll fix these and print another...
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