In that case, this is a bug that crept in somewhere along the way, and should be
an easy thing to fix.
the original āmeasure by chainā strategy was to run both motors to the right
after you hook up the chain to give you enough wrap before pulling the chain
tight.
we are watching the encoders on both motors, so we know how far each of them
moves, so we can just add the two positions (add, not subtract, because the
right motor is moving in the negtive direction to take up the chain)
ideally, pulling tight should apply power to both motors so we can see if there
is any flex in the frame.
It should be an easy modification to allow moving both motors to the right to
gain more wrap before pulling tight.
Itās been like this since I got the Maslow in November. You install the chain on the right motor as I showed in the post 4. After that, pull tight and the left motor takes up slackā¦ repeat a time or two and hit measure. Thereās no reason I can see to change it since itās really simple to do.
I just calibrated again tonight and didnāt have an issue with it slipping and I think many, many people as well have no issue. A simple spring loaded clamp like @Tanker51 suggested solves the problem for those experiencing it (perhaps thereās a difference in the sprocketā¦ dunno).
I often use a clamp like that too. Belt and suspendersā¦ 
If āsomeoneā had overlooked getting the right sprocket lined up just right, or the moon was wrong, or heās in a hurry to get done, the chain will jump off. And knock one of the heat sinks off the motor board on its way past.
How on earth did you see me do that???
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I had this issue - about 12 times. It was pretty frustrating. Using 2 people, however, it went smoothly twice in a row.
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@bar, is there a difference between the sprockets that were previously shipped out and the sprockets that are now being shipped out?
Nope, no changes to the sprocket design
Hi all! Thanks for all of the feedback and things to look out for. I have been successful at keeping the chain on the sprocket but the motor pull was so great that it shifted my Motor mounts so Iām working on correcting that now. Since I am doing this by myself, my solution to keep the chain on the right side during calibration was to take a small hooked bungee cord and insert it into the end chain link, after placing the third link over the vertical tooth on the right side, then attach the other end of this bungee cord to something else. The tension from this bungee cord kept the chain in place. The issue now is the wood screws I used to hold the side motors brackets were not placed at the extents of the slot. when the motor tightened the chain, both motors rotated around these wood screws. Correcting this now but using the full extents of the slots in the motor mounting bracket. My only concern now is my design has the chain connecting to the sled from under the sprocket, instead of over. I noticed this was the next step in calibrating but I cancelled setup so I could fix the motors. Things should go smooth now.
I also had to adjust the base frame design where the motors mount to accommodate the chains lining up with the COG of my sled. I will post more about this in a separate post after I am making saw dust! 
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