Flatten job Z-Axis drives 1/2 into project

[TheMan1352 (Vance Mowery)]

I am running a .040 flattening job. 1/2 way thru it looks like it might be cutting slightly deeper and then on one leg it just started to run deeper into my project 9” until it was 1/2 inch deep onto the wood. I also have a problem when i turn off the machine that the spindle runs down until it hits the spoil board. It acts like the machine cant hold up the spindle.

[SLCJedi (Josh Tenny)]

Issue A - Make sur ethe endmill didn’t slip down in the collet.

Issue B - That is normal. C3D assembles those pretty accurately, so there isn’t much friction to hold it up once the steppers are powered down. It holds up a router just fine, the 65mm spindle some of the time, and the 80mm spindle never. Progressively gravity does it’s job the heavier you get. That’s why if you get their 80mm spindle kit, it comes with their strut to hold it up when powered off. You can also purchase it separately here:

Gas Strut for Shapeoko 5 Pro

[TheMan1352 (Vance Mowery)]

I got the strut installed, thanks for the suggestion.

[No_Soup_For_You (Dean F***)]

I think I’ve read similar situations before where the gas strut was actually failing or defective or something. Either way best bet for this is probably reach out to support as it’s unlikely to be anything else besides maybe a faulty controller.

[CullenS (Cullen Simpson)]

Below is a post I did on slipping earlier in the year. I started being super careful about cleaning the nut, collet and shaft at each bit change. It happened less frequently but still would on occasion.

My collets all measured slightly differently and I couldn’t get a real answer on what they should read. The ones I had the most issues with were newer C3D precision collets. Certainly possible that the variance in the collets was due to issues with my calipers.

I eventually upgraded to a 65mm spindle and the ER-11 collets. I was really surprised at how small those things are. I realize that not that many people have this issue, but it became a super frustrating experience making me not want to use the machine.

Bit slipping. Bad collet?

I did use the marker method, pictures included above. That is how I knew it was the bit slipping rather than the Z lowering which many people assume. I agree that tightening up should resolve the issue, but it is not in these cases so it feels like something has changed. The collets that work for me are the ones that are snug when I slide the bit through. The collets that fail are the ones that the bit slides through like butter. So, if it isn’t a collet issue I still have something else to tr…

[No_Soup_For_You (Dean F***)]

Good advice I assumed because he Joined in may unless he was running it as a full time business that shouldn’t be the case. Also the spindle dropping isn’t a frequent thing for most 5 pro’s unless you have excessive weight on it and even then mine doesn’t drop unless bumped with a heavier festool hose, 3/4 ply vacuum bracket, sweepy, airblast, and a chipguard collet I made on all at the same time.

Edit: no gas strut on it either