Sienci Labs LongMill MK2, Assembly Manual

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On the coupler, identify the end with the larger hole - this will be the only side that fits onto the lead screw. Push
the coupler on until it bottoms out, then tighten the ‘lead screw side’ set screw using an M3 Allen key.
BEWARE!
Only tighten ONE of the set screws - the one on the lead screw side (as pictured). You’ll tighten the other set
screw near the end of machine assembly. If you overtighten the wrong set screw it can deform your coupler and
cause assembly issues.
Now rotate the coupler and ACME nut in opposite directions so that they come together to clamp onto the two
bearings. Once they’re together, making a ‘bolted sandwich’, everything should be touching (as pictured). Once
in this position, tighten the set screw on the locking ACME nut. If assembled properly, this should now feel like
a solid, single piece where the lead screw should only be allowed to rotate, and not move in-and-out. Set this
assembly aside for now.
Use M3 Allen Key