tldr; just jump ahead to the gotcha list
After assembly and initial testing all of my arms extended but only 2 retracted. One of the arms that wouldn’t retract would at least budge when I attempted retraction. After a few iterations of extending a bit and budging during retraction it finally mostly retracted.
This was not true for the last arm. It wasn’t until I cranked the retraction force up to 2000 that it started to budge. Even at 2500 it wouldn’t always fully retract with one attempt (gotcha #6). After repeatedly extending it and retracting it over and over, bit-by-bit and again all at once, with significant manual resistance and again with no resistance. I was able to get full retraction at much lower force settings (or so I thought, see gotchas #3-5)… until the next day when the retraction was almost impossible even at 2500 again.
I noticed though that if I could pry the motor away from the router that suddenly retraction worked even below 1300 force! (gotcha #8)
After backsliding and finding no good way to adjust the motor I decided to remove the 34 bolts to get inside the troublesome arm. Once I pulled it apart I realized this was the arm I had to really force the idler to fit. During assembly I wasn’t able to test the idler gear fit before the thread lock cured because I had to wait a couple days for the missing idler gears to get sent (gotcha #1).
I was able to remove 2/4 of the lock threaded bolts holding on the motor. The other 2 were stripped and stuck (gotcha #2). It turned out to be enough to get some breathing room. Putting it all back together the idler gear went on much easier.
After reassembling everything the troublesome arm was retracting without issue. I’ve since had more problems with a different arm retracting the last 6 inches on the first attempt. Its good enough to get by (I just have to retract multiple times). I have noticed near the end of the day when the garage/outside temperature is near its peak and the motors have been running for a while that it will consistently retract. In the cold morning and the first few retractions of the day however it will still get stuck (gotcha #7).
Gotchas:
- Fit the idler gear at the same time as tightening the motor to the arm to make sure its not too tight.
- Don’t over-tighten the bolts.
- Save and Refresh (FluidNC blue button or browser button) is not sufficient to apply the config values.
- Restarting (FluidNC red button) will apply the config values but only if you see the count-down/progress-bar timer and hear the Maslow click/cycle. Sometimes pressing the red button will not actually trigger a restart.
- Sometimes the browser cache will persist log entries between page loads potentially hiding information. You might want to clear cache or open a new browser instance.
- 2500 retention force did not break anything after several extension and retraction cycles. It also didn’t really fix anything.
- You might have more luck when things are warmed up, conversely things might get worse when it cools down at the start of the next day.
- Pry the motor away from the router to see if it helps/hinders retraction force.
Bonus gotcha:
Don’t use lock nuts on the belt ends. They are taller and the protrusion will make them more likely to bind at a funny angle with the wingnut causing an inaccuracy in the belt length.