Feed rate detector/sensor

After having some problems with bits bogging down and even snapping in birch plywood, I was wondering if it might be possible to add some sort of linear motion sensor that would continuously sense the actual feed rate, compare it to the set feed rate, and if the actual rate drops too much lower than the set rate, automatically stop or pause the carve or, at least, stop driving the carve at a feed rate which the machine/bit/material can’t handle?

Hi Rick, all those symptoms will go away when you start mastering more. Yes it is good idea, you can set limit switch configuration (Not Homing Switches) put one limit switch to bottom of your Z axis. You have to make that switch adjustable by the material thickness every time.
Other than that, there is Hard Limit configuration you can change on your Grbl setting, but same thing, you have to change that limit ever time you change your material thickness.
I haven’t done any of these. But you can find plenty enough information if you search this forum.
My best practice is making solid Z zero adjustment with touch probe, checking my dept and feed rate numbers again and again before sending any job. And most importantly I don’t ever push the limits, going easy.
I was diving into material once at the beginning, it was 24V spindle failure. Problems disappeared after I switched to Dewalt Router.
Hope it helps.

Thanks Alan!

I guess I should have mentioned that I don’t own the machine I’m working with. It’s a Shapeoko 2 at the nearby Makerspace with a Dremel as a spindle. So I don’t have the option of adding switches or changing to the Dewalt. But the problems I’ve had just made me think that adding a linear motion sensor might save some novices like me some headaches in the future.


Rick J.

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feedrates on machines with stepper motors do not vary with load. There are only 2 states: “correct speed” or “stalling” due to step losses. If the motors stall feedrate is just too high and needs to be lowered.