Wrong z axis depth

so I’m in the middle of a project and am carving my piece in stages. the one part of the carve i told the machine to carve at .17" and it carved at .23"

It has been working fine before, so I’m not sure what the problem could be. that was also my roughing pass, So I’m worried that my finishing pass won’t match up at the bottom of the pocket.

Any Ideas?

So just shy of 1/16". have you checked for the waste board being level? I know it’s basic but it takes simple questions to nail everything down.

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yes the wasteboard is level, my previous cut was fine, belt, v-wheels, delrin nut and acme rod all look fine. stopped the machine and jogged it up and down with different heights measuring after each time, totally fine.

one other thing I would check right off since you said you were using upcut bits, is make sure the bit didn’t slip down in the collet. Upcut bits can pull down pretty hard. I had that happen to me in the first week of using my machine. Collet was not quite tight enough.

This particular carve I was using a 1/4" 2 flute straight bit. not sure that was the case. but good to keep in mind for when I do use my upcuts. Thinking of just replacing the upcuts, got them fairly cheap, but have had nothing but headaches with them.

upcuts are brilliant for plastics, composites and metals. They are meant to pull the chips up and out of the hole.

Software?

was using easel

Have you checked the material is flat? Sound a little dumb but my first real project got me like that. My Red Oak was not quite flat. But you couldn’t tell unless you really looked for it. As I’m not really familiar with Easle (I run most things with Aspire/UGS ) not sure if that could be a problem within the software.

I’m pretty sure my material is flat, it’s 1 1/2" thick and was planed on both sides.

Zeroing the bit to the face of the material is easy to mess up without a zero plate. I either go too light or too deep by “eyeballing” it personally. Another thought is how do you know your material is a perfect level thickness as well (even planed it can still be off). if the point you zero too is off .06 from the location of the actual cut you need at a specific depth your machine does not know so if the clamping causes the material to flex a bit or bow up at the point the cut will be made it will go deeper than expected.

That and a planer is designed for thickness. You have to joint one side first. If you just plane both sides then you make the material thinner. Not straighter. Just thinking that maybe the problem is with the wood. Not the machine. We usually use planers and jointers to make the appearance of something nicer. Doesn’t mean that they are “machine shop” accurate. Just because it looks perfect doesn’t mean it is.