Losing steps in x and y

I’ve been doing a lot of cuts through solid maple lately. It looks like I’m losing steps on both my X and Y axis when I’m cutting front left corner. I’ve checked all my belts and v-wheels and they seem to be good. Any suggestions/guides to sort this out?

You’ll need to decrease forces on the cutter.
Can you share your endmill specs, feedrate, rpm, depth of cut?


1/8 - 2 flute down cut (I’ve used an upcut with the same results)
10k rpm (makita router 1.5 setting)
1/8 depth of cut

I actually think I’m losing the steps because of rapids. I don’t lose steps anywhere else on the machine. My cuts are the entire size of the bed.

That’s a 0.003" chipload at 100%DOC…which is a bit aggressive for hard wood in my book. The poor chip evacuation of downcuts probably does not help, especially if you are slotting ?

I would reduce DOC to 50% (1/16"), which is the most direct way to reduce cutting forces, and see if this changes anything.

Any chance you might be positioning the stock too far left/front of the work area, and at some point during the cut the endmill reaches the limits and you lose steps there while contacting the left rail/front plate ?

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I should mention this is an S3 XXL with a Z-Plus

I can try the 1/16, but i’ve run at 50% and it still does this. The part where I am losing steps is 9 small .25" circle pockets that are only .125" deep.

I’m definitely not going too far left with my stock.

I really think i’m having an issue with the machine not being square/belts/v-wheels.

You could try dropping the max speed for rapids down a bit through the MDI page. I think the default rapids speed for grbl ‘v1.1f’ in the shapeoko is 10,000 mm/min (it used to be 5000 mm/min in grbl ‘v0.9g’).

I just installed Carbide Motion v5.21 a few days ago (from 2 years on v3.68) and dropped my max speed to 8000 mm/min, I am much happier with the sounds of the steppers at that speed…

To do that first open a log window, then type $$ in the MDI entry field and click on send. Make note of the values (copy and paste them into microsoft notepad and save it as initial values).

Then, in MDI, type $110=8000 and click on the send button.
Then type $111=8000 and click on the send button.
You can make adjustments to the z-axis as well ($112=…), but I didn’t because I just installed a z-plus (has different settings from belt driven).

You can also make changes to the x, y, and z max acceleration, but I don’t want to tell you to do that as I haven’t done that myself. However, if nothing else ends up working, it does seem like a logical place for steps to be lost if forces exceed belt friction on the teeth.

Maybe someone else can ad their advice as well…


Turns out we were all wrong. The left Y stepper motor set screw was loose :roll_eyes::roll_eyes::roll_eyes:


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