Completely disassembled my @Printrbot to update to 1405 version. Got to step 24, assemble z axis and find there are no set screws in the coupler or anyplace else.
The coupler wasn’t machined with the spiral cut either.
Argh, no printing until this gets straightened out.
I’m trying to make the upgrade from my vintage 2013 simple and discovered I need to buy two new motors… And it seems they are difficult to source in Europe.
So what do you do about the coupler?
While you’re at it, you might want to confirm you’ve got a delrin nut to mount the Y-arm to the Z-screw - my kit didn’t include one.
@Patrick_Ryan they have a pop up on the order form to get the delrin nut.
I upgrading an upgraded beta version so also do not have all large motors. I have three. @Kai_Laborenz I used smaller motor on the Z axis with no problems. Had to keep the X rails lubricated when X was driven with a small motor. i suspect large motors are needed where the acceleration * mass is greatest? Makes sense as F=ma
@Robert_Roberto I’d get some set screws if I knew the size. it’s not M3 or M4 apparently. Not spec’d in BOM either @Brook_Drumm . so up the creek without a paddle.
@Alan_McNeil I followed that logic for the Z-motor and found that it couldn’t handle the G29 command for the auto-level. Had to get bigger motors and tear apart my build to replace it. YMMV.
Sorry to hear of the trouble! I am sick they left out your grub screws. I’ll find out the size. I asked my guys to follow up and send you the spiral cut if you want. The coupler was made in a local machine shop. I’ve been running it on my bot along with others at the shop and love it. As long as you install it and get I running straight - it’s rock solid. Also I move my bot around a lot and it helps avoid auto z level surprises 
the coupler is more expensive, oddly, but it’s my new go-to option when sourcing problems happen with the spiral cut… Which is exactly the case here. That’s fixed now but now I have two sources. We’ll send you what you need ASAP- just fill out a ticket. I emailed 3 guys about it.
Service on a Saturday morning. +1 to @Brook_Drumm and the @Printrbot team.
@Brook_Drumm i definitely need to build a stock for the single upgrade / replacement parts, so i can send that stuff out on a Saturday morning from Germany to Europe instead of you guys sending it from the US
Thanks @Brook_Drumm , I’m a bit late on filing out ticket. My daughter got sick and (usually) takes priority over printing problems.
Took the coupler to Home depot to guess size of set screws. Seems to be M4. Amazingly Home Despot now has some M3 and M4 bolts. Picked up a pair. Will try that for now.
@Alan_McNeil hope your daughter gets well soon
She is resting now about 15 feet away. Nausea. So back to building the next gen printrbot. Best thing I ever did was get a wheeled workbench. The common area is all linoleum floored so I can move it easily. I’m a bit weird as the bench is next to the grand piano and nice paintings. It’s all creative stuff, right?
@Jeremy_Gallegos Thanks. I went to local hardware and tried M4 and 6-32. M4 wins. I’m still dead in the water due to new problems