First cut (after the sled) went awry - chain jumped off

So I got my Maslow put together, and after some issues with the zaxis fixed with a 3d printed part, I managed to cut the final sled without issue.

My first project was to cut some sawhorses. I found the dxf file online, imported it into fusion, and followed this tutorial to get a toolpath generated and export a gcode: Fusion360 CAM for Maslow Tutorial - YouTube

I cut the sawhorse in the top left corner of the stock, because that was the least effed up part from all the testing and sled attempts. As it cut the top, I guess it jumped a tooth and got off. I didn’t notice right away, and it seems like when it came back around, the chain jumped off the sprocket and the sled fell. I was able to shut the power off, and the damage doesn’t look too serious, but I’m trying to figure out what I did wrong.

Since I can only post two links, I’ve shared the GCode, a screenshot of GC, my fusion file, and a photo of the aftermath here: Maslow Disaster - Google Drive

Any help would be appreciated, I’m a total noob at milling. I’m planning to put things back together and cut a new sled, but I won’t be creating my own tool paths until I understand what went wrong.

Jumping teeth happens in the upper corners most often when the chain isn’t parallel to the work surface. You need to reset the chains. it is likely not a problem with your gcode. There was a discussion on chain routing paths recently that may be of interest. The summary was captured in the manual chapter here and there is more if you scroll down to chains where this diagram is:


Yeah, it was the top left corner of the stock, so I bet that’s it. I’ll check the chain alignment and give it another go!

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first thing to check with any chain issues, is the chain parallel to the
workpiece (or very close to it), chain is designed to work at only a couple
degrees off of straight, and as you get close to the motor, the angle gets worse
for any misalignment.

first, find the height for your ring that makes the sled hang straight (with the
router at a reasonable cutting height, the router is a LOT of your weight)

then you want to make it so that your chains are parallel to the workpiece,
either by adjusting the frame to move the top beam in, or by adding extra
wasteboards behind your workpiece to push it out.

David Lang

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