4th axis brake enquiry

[m_c]

I just remembered I bought a few of these a few years ago. Very high quality wormscrew mechanisms. Might be worth a tryout
Rino Ondrives Worm Gear Reducer 30:1 Vexta Nema23

They're certainly worth trying.

They look like a top bit of kit - accurate to about 0.1 degree if I've read the Ondrives data correctly.

Looking at the OnDrive website for Nema mount version, it looks like you can get either an 8 arc minute, and a 30 arc minute version, which is 0.1333, or 0.5 degrees.
It all depends what kind of accuracy is needed. 0.5 deg works out about 1.3mm of movement at a 300mm diameter. Off course the 0.5deg figure is the worst case scenario.