Spline IK Deforms mesh at default pose

This may be a dumb question but I’ve never used Spline IK before. I’m rigging a Minecraft Iron Golem which has a 4 segment arm. I wanted to use a spline to deform the arm. I have 4 bones, each weight painted to one segment, and a curve running up the length of the arm. When I set up the spline and set the chain length to 4, however, the scale of the arm segments change, deforming the mesh and textures. Is there a way to prevent this?

This was made in Maya, but at around 1:40 he demonstrates the effect I’m trying to achieve

<a data-cke-saved-href=“https://www.youtube.com/watch?v=AnU5mnLTYLc” href=“https://www.youtube.com/watch?v=AnU5mnLTYLc”>
https://youtu.be/AnU5mnLTYLc

Any help would be greatly appreciated! Thanks!

irongolem.blend (882 KB)

Just a note, the file is set up with a regular IK because I tried that after spline didn’t work