Having Consistent Depth Of Cut Issues

I’ve had my pro xl built for a couple of weeks now and after quite a bit of playing around, im still having a devil of a time trying to get decent results. Right now I’m working off a basic piece of gcode i made up in carbide create, a square cut out of a 4’ x 6’ piece of .064 thick aluminum with a contour tool path and 1/8’ endmill. The speeds and feeds im using are the default for the endmill : .010 depth per pass, 20ipm feedrate, plunge rate of 5 and 10000 rpm. Basically what im running into is even with setting my z zero just touching the stock, my machine cuts air for a few passes before hitting material. Then when the endmill starts to make contact, it plunges too deep resulting in very rough results and damaged endmills. I’ve attached a photo to illustrate what im talking about. I stopped the run before it finished as to not damage the endmill further. I tired disabling the bitsetter but still having issues. I suspect my wasteboard isnt perfectly level as my hello work marker test was a little heavier in some spots, but would that cause my cuts to dig in as much as they are? Any help would be greatly appreciated!

Let’s rule out a few things:

  • how are you setting Z zero? If right after you zero, you jog manually down to Z=0.0, are you spot on at stock surface? How high above the stock does the endmill run in the air during those first few passes ?
  • assuming this is the case, if you then retract Z by e.g. 5mm then jog to other places of your stock and jog back down to the stock surface, is the delta exactly 5mm everywhere too ? If not, your stock is not level. Did you surface your wasteboard ?
  • Can you upload your c2d file and generated G-code file for a check ?

Sorry for the many questions :slight_smile:

1 Like

What grade aluminum is that? Also how are you holding it down so that the endmill doesn’t suck it up?


Looks to me like a wasteboard that is not level. Took me a while to realize how important leveling/sufracing the wasteboard is!


Thanks for asking so many questions so i can hopefully sort this out :slight_smile: I’ve been setting my zero by first clearing all offsets, jogging to the bottom left of the stock and bring the z axis down so i can just wiggle a piece of paper between the endmill and the stock and then zeroing all. I have not surfaced the wasteboard yet though i know its something i should probably do to eliminate the possibility of waste board unevenness. I’m a little nervous to try is as i don’t want to muck up the nice supplied mdf on the hybrid table, are then any guides you could point me to that a newbie can follow?. I’ll post my gcode when i get home, I think i did everything right but a second opinion would be great.

The grade of aluminum is 1100 and ive been using the double-sided tape from the work holding kit to hold it down.

That is pretty much commercial pure aluminum and is gummy and soft. I would suggest going up to a 6061 grade aluminum or using a single flute tool and some type of light lubrication. Also sometimes double sided tape has a bit of give to it, should be ok though


I’m going to echo a few things based on my experience.

A - As i3oilermaker pointed out, your depth issue is 90% likely to be the wasteboard not being level. I have seen on the 2 SOPros, and 1 SO4 that I have set-up, that there is around 0.020" of variance across the working area. That doesn’t sound like a lot, and meay work for a lot of uses, but small depths of cut and aluminum make for a less forgiving project. MDF is about the cheapest material suitable for wasteboard usage…don’t be afraid to cut into it. If you want, make a set before you cut into it. :slight_smile: It is made to be abused, and the slat system on the hybrid bed makes replacements cheap and easy to make as well as store.

B - As Vince.Fab pointed out, that alloy of aluminum is a worst case scenario for machining. 6061 is optimal for machining, but if you’re doing sheet work, is hard to find. I have cut 5000 series aluminum sheet and it worked well.

C - Tools…single flute on aluminum are your friends. I will use a 2 flute for a 1/8" if I don’t have a single, but I will not use anything but a single flute with a 1/4"


@SLCJedi is the guy you want to talk to, I used his tricks to surface mine :slight_smile:
Josh, do you have a copy of that FB post you made explaining the steps to surfacing?

1 Like

Yeah, I know 1100 is not great for machining but its what i have lots of scrap so i thought it would work well enough for test cuts while i’m trying to get the hang of my machine. I’ll definitely see about sourcing some 6061, i know a few folks in the fabrication world who might be able to help.

1 Like

I actually bought a few single flute endmills with my machine but I don’t want to use them until im a little more confident about how things are running. I’m just using the carbide essentials endmills right now so i’m not breaking any expensive bits with my learning process. As Julien said, any advice you could share on wasteboard leveling would be fantastic.

Here are the posts I’ve made in the Shapeoko/Nomad FB group, there may be others as well:


Thanks for the links but i’ve actually never bothered with a FB account so i can’t view it. Any chance you could post the important stuff here? Also, does the hybrid table mdf need to be surface as well as the wasteboad you put on top? Or is surfacing the secondary wasteboard good enough?

I’d second the single flute in Aluminium advice.

Especially in the softer stuff trying to keep a 2 or 3 flute from jamming up with goo without either air blast or lubricant is a constant challenge, single flutes are just much better at throwing chips out instead of welding to them.

I’ve had some success with Isopropanol as a lubricant on Aluminium cuts where I had chip evacuation troubles and it does help, but not as much as the right cutter.

Not all single flute are expensive, I buy cheaper DLC coated single flute 4mm cutters over here for ~ $10 each. They’re not as nice as an Amana, but I’m less upset if I break them.


Looks like I posted the Pro info here. :slight_smile:

I use a different pattern now that is staggered.

1 Like

That’s great info, thanks a lot. Question for you: is there a reason not to just create a very shallow pocket tool path with a surfacing bit to run the length/width of the full cutting area?

That’s a valid approach — it leaves a lip around the cutting area which is problematic for some folks — a spoil board the size of the working area, plus surfacing endmill diameter w/ radiused corners works for some folks.

1 Like

Many people do just that…a large pocket. If you never cut a larger piece that works great. I often do pieces that are slightly larger, so I wanted the work area to sit proud of the area the endmill can’t reach.

Many people use another wasteboard on top of the slats. But I wanted unfettered access to the t-track.


Yeah, that makes sense. One more question and ill leave you guys alone. I have been using a second wasteboard on top of the hybrid table mdf. Is it enough to just surface the second waste board, or is it best practice to level the mdf slats as well?

That. What’s important is the “final” surface the stock is lying on, regardless of the stackup geometry below that

1 Like