Zulagen hurts my brain

Hey kids! Winter break’s over, so here’s a puzzle to thaw out your brain.

You know those mental rotation exercises that are all like this:

Mental rotation exercise puzzle with Beijing's CCTV tower

Well today I give you a violin maker’s variation on that exercise.

I almost broke my brain making zulagens. Zulagens are little helpers that redirect clamping force to where you want for glue-ups. Here, a page out of my notes to explain how it’s used:

0104 zulagen

This zulagen pushes on the ends of the C-bout ribs, and the serrated face reduces slip during clamping. It’s important for the two sides that push the ribs to be squared up nicely. Before you serrate the face, this is what you want:

0104 quiz 1

No light passing through the inside edges of your square.

But this ain’t your regular blocky block! The square reads diagonally across the reference surface (labeled “DOWN”). Sure, you can just flatten your DOWN surface and then square up each angled face individually, but why make it so easy when you can make it WAY HARDER THAN YOU NEED TO?!?!


Turn on your planing brain, it’s time to figure out how to square up the two angled faces with minimal planing.

Based on the light passing under the edge of the square, where should you remove material if you wanna get the job done in one go? Each question has ONE SINGLE ANSWER ONLY!


Let’s do the first one together:

0104 quiz B

The face on the right is fine and good, so the answer has to be A or B. The other answers would affect the squareness of the right face (Remember? Square goes diagonal on reference surface). The left face is reading bigger than 90, so you want to decrease the angle. The right answer is B.

Okay, you’re on your own now. Hover over the image for the answer. Remember, pick only one.


Get warmed up with this one, which is similar to the example.

zulagen mental rotation planing puzzle 1


Now for the good stuff.

0104 quiz 2


0104 quiz 3


0104 quiz 4

So, how’d you do? Comment below if you want to brag (or whimper, or correct me, or point out some technicality that invalidates the whole thing).

And now, circularity for closure.

escher cctv tower


Luthier Lammily

My thoughts on the new Lammily doll:

  • Great idea! I support the concept.

  • Barbie’s proportions are obviously disturbing, but I used to excuse some of it as due to design challenges (i.e. maybe joint articulation forced weird things to happen to her legs). Not anymore! Lammily is well proportioned AND more articulated than Barbie. In fact, I think as a reference model, I would even consider her over those wooden mannequin thingies that artists use.

  • Since her appeal is largely due to how “real” and thus relatable she is, the request questions are pouring in in their comments sections: “When will you make a Lammily with different skin/eye/hair color, body shape, fashion accessories, etc.?” It’ll be interesting to see how they develop “career options” for Lammily. So let me just save them the trouble of research & development should they ever decide to make….

1214_luthier lammily

luthier lammily clothing and accessories

Explanation of all the clothing/accessories:

  1. Apron, duhh.
  2. Work boots.

  3. Magnifiers.

  4. Biceps/triceps enhancer for one arm.

  5. Plane. I wish I knew about planes when I was a kid. Little brass fingerplanes are so cute, so why aren’t more girls into them?? I didn’t know what one was until college!

  6. Bandaids are an important part of our lives.

  7. Jeans.

  8. Plaid shirt with a hole on the elbow. Why plaid, you ask? Because this is pretty much an everyday occurrence at our school:

1214 luthier lammily 3

Yeah, I made this entire post just to lead up to this photo.