Going to try a more powerful stepper a 3Nm one against the ones I have fitted 1.8 Nm.
Looking for others I found a nice little one on Arc euro a 3.5Nm but noticed something a bit odd in the datasheet, they are quoting 3.5Nm holding for parallel and 5Nm for series most other datasheets show the same rating for both. Is this correct or a miss print.

peter