I have been cutting with the temp sled (mostly) without issues. I just cut and calibrated the permanent sled, added the bricks and now the sled seems to pop and drop. I’ve watched the motors, they don’t seem to be skipping, but the sled also doesn’t seem to be stalled either.
I’m cutting at 22k rpm, 1/4 inch but, .2” depth and 30fpm. It only seems to be an issue when I’m cutting horizontally.
I’m going to reduce the brick weight and do a dry run. Anyone have any suggestions?
I suggest trying to reduce the weight. How much is the sled weight at the moment. Backup your groundcontrol.ini file. If you still have an issue try going back to the temp sled to see if this is repeatable. Did you use both bricks on the temp sled? What version of the Software/Firmware are you on?
Thank you
Sounds like a chain skip (hear a pop and then the sled drops). You will need to recalibrate once you solve the problem. Check the alignment of the sprocket to the sled. They should be on the same plane. I’ll find the link to a thread that discusses this…
I didn’t use any bricks on the temp sled. (maybe I’m not good at following directions?)
Ground Control : 1.04
Firmware : 1.04
Weight is 26.6 lbs
I Just read : (https://github.com/MaslowCNC/Mechanics/wiki/The-Router-Sled)
Ideal sled weight currently is somewhere near 18lbs, as described in the Assembly instructions, but developers and builders have experimented with weights much lower, approaching only the weight of the Ridgid 22002 router and sled alone. (approx 8-9lbs)
So that is likely the issue.
Any thoughts if skip like this would have permanent damage to the motors?
Problems aside, the first piece I cut out, was cut beautifully.
I wouldn’t expect a chain skip to cause any damage. I think enough people (including myself) have experienced chain skips without reporting an issue after the fact.
Temporary frame or final build?
Chain mount system to the sled (Original brackets or a Triangular Kit)?
I agree that the pattern looks much like the chain jumped, that, you can hear clearly and loudly if you are there.
Slightly similar patterns I’ve seen with brackets and a sled that hooks and releases. This is clearly visual. A video with audio would give final clues guess 
I agree that it sounds like a chain skip. It happens really fast, it wasn’t until I used the slow motion video thing on my cell phone that I even believed it was happening. I would check that the chains are feeding cleanly and that everything is in plane. Moving onto the the final sled may help.
It is chain skip. Seems to not be enough tension on the slack side of the chain. Applying more weight with my hand seems to fix it. I may add more tension to the band, or 3D print a chain guide/guard
Making a 3D printed gear cover is on my todo list.
Thank you
I was wondering if there was a reason there aren’t rollers to prevent chain hop. Concern of jamming and damaging motors? Leaving the ability for skipping as a failsafe?
I’ve had no issues but a cover with idlers would help keep it in line or the chain will tear them apart. Unfortunately it’s like #40 in the list.
Thank you
Folks often use a guide on the slack side of the sprocket, but the chain on the sled side of the sprocket needs to be free to leave the sprocket from any angle due to the way the kinematics math works.
it wasn’t expected to be a problem, the later kits do have an improved chain
guide, and the new instructions reposition the chains so that there is far less
chance for them to skip.
@mrfugu’s solution also does not require a chain guide, which I found really simplified my setup. It is the simplest and quickest solution to chain skipping that I’ve seen on the forum, and certainly worth a try if attempting to determine if chain skipping is the problem. The downside with the solution is that the roller has to be removed and replaced for chain calibrations as the chain cannot be removed from the sprocket while it is in place.
@mrfugu’s solution is very useful. Thank you @Keith & @mrfugu
@bar and @dlang This will be helpful with the new Motor Mounts.
FYI - I will be putting a clear coat on my set. I suggest some kind of paint or they will rust eventually.
Thank you
I’ve also found that moving the chains to the top bar (the ‘bottom feeding’ configuration) helps make them feed more smoothly. It’s still a little bit beta, but the software does support it in 1.07.
Putting the chains across the top does two things which are good. First more teeth on the sprocket are engaged especially near the top where tension is the highest. Second the chains are kept in plane the whole time which helps too.
Do you have a photo or illustration of this method? I’m getting chain skip and slack miscues regularly.
Have a look here -
Thank you