Z Gantry Position - Learned a New One

[jeb2cav]

I thought I'd share a new lesson learned - at least for me.

I was running a quick v-cut for some lettering on a sign. The letters were nowhere near what I saw in the preview, so I reran the toolpath in VCarve and saved off a new tap file, and ran it again. No change. I don't cut a lot of letters, and the bit I prefer to use has a relatively short shank. I was able to set the 0,0,0, and I knew I was on the far side of the z travel extent, but didn't think to check to see just how much travel was available after setting z0.

So, to give you a sense of how shallow the cuts were -

Shallow Cut

After the second attempt at running the project, I decided to look a little harder at the hardware, and not the software. I first performed a move to 0,0,0 - the bit was about 0.3 above the z0 I had set at the start of the project. I didn't check that the first time it "failed". So, usually when it doesn't return to 0,0,0 after the job, something happened - ran into a clamp, feed rate too aggressive, etc.

Now a z obstruction would be new for me. I have done a few bonehead things that had me scratching my head - like the time I left the hand broom resting on the gantry rails - and the x axis travel was blocked. That only took me 2 wasted pieces of wood to figure out...

So, I set the z0 again, then lowered the z slowly until it ran to the end of the travel. There was about 1/8" of travel "left". Of course, looking at the z gantry after setting z0, I might've thought to check this before running the job...

Gantry at z0

Fortunately, I was able to raise the piece and maintain the x,y 0 location, and cut again, so no wood lost. And, after raising the piece and resetting the z0 - it now had enough z travel capacity to cut as shown in the preview.

Depth of Cut as Expected

Not something many will run into, but maybe this will save someone a few headaches.