DOC for 800W spindle, any other advice?

I have purchased a 800W water-cooled Huanyang spindle with a 1.5KW VFD. To my understanding, the feeds and speeds should remain the same, but the DOC will increase (please correct me if/where I’m wrong there). That said, how do I find the right point of that DOC? What are indicators (before damage to the system) that the DOC is too much?

It is pretty difficult to answer your question. It depends on what materials you are cutting, type of endmills you are using, type of toolpath, geometry of the part, etc. There will be a learning period while you get used to your new spindle. Here are two resources that are really good for helping you build up the base knowledge that will help you determine the right F&S for any situation:

And this Excel workbook/forum thread:

I did the same upgrade and have loved it. One thing to know is that you are unlikely to break anything more than an endmill if you get your F&S wrong. The shapeoko is very robust and hard to break anything that would be expensive to fix.

Thank you. It looks like I have a fair bit of reading ahead of me. Up until this point I’ve been doing exclusively wood, with 90% of that being pine, a hair of walnut and maple filling in the remainder. While I can see a shift towards more hardwoods, I don’t really see myself doing metal working in the future. Just have a couple neighbors with massive metalworking shops within a couple blocks, so I can toss those odd needs their way, stick to my interests.

I feel fairly comfortable with the softwood settings on the default shapeoko library, sometimes I’ll kick it up a bit on the IPM, but usually nothing too crazy (ie, no more than 20% above recommended levels). It’s been pretty good so far. I just didn’t know if there was a way to say a rule of thumb that if you did X DOC with the carbide router, you’ll do 3X with the 800w spindle (or some other factor). If such a rule exists, I’m all ears, but still, looks like I have some more learning to do.

Carbide Create (I think that is what you mean by “shapeoko library”) is extremely conservative with the default F&S settings. I have pushed my machine easily 2-5x harder than those settings. As you learn (read: make mistakes) you will be able to push your machine much faster. Learning about feeds and speeds is like drinking from a fire hose. Don’t get overwhelmed and don’t be afraid of making a mistake.


FSWizard is the opposite and pushes the limits. A nice feature is it shows the HP needed for a given recipe. (Your 800W spindle is right around 1HP). And you can change the DOC & WOC (stepover) and see the resulting HP needed.

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As @nwallace mentioned but that various things to factor in, but to be it bluntly, I don’t think the spindle upgrade will do much (if anything) regarding increasing max achievable DOC. A spindle (and a water-cooled one at that) is a great way to have a quieter machine, and in some cases a lower runout for detailed work with very small tools. But DOC, that is pretty much bounded by the machine’s rigidity limits and the rigidity of the workholding.

There is a fantastic thread by @LiamN about deflection (among other things), and while the Shapeoko3/4 is quite a capable machine, at some point its ridigity at the spindle level will be limited by the v-wheels. Hence why the Shapeoko Pro with its linear rails improves on that aspect, and allows for greater DOC. Larger/heavier industrial machines that weigh a ton will be even more rigid and allow even greater DOC.

On a Shapeoko, you don’t necessarily want to max out DOC anyway, it has been proven that it’s more efficient (in terms of material removal rate) to use a moderate DOC but more aggressive chipload (RPM & feedrate). To feed faster, while maintaining a constant chipload, you need to also increase the RPM. And that’s where the spindle shines: the noise of a spindle at max RPM (usually 24.000RPM) is much more bearable than a trim router screaming at the same RPM. So once you upgrade to a spindle, you tend to use the higher end of the RPM range much more often than when you have a router, or at least I did. And that enables/requires faster feedrates, so higher material removal rate (at the same DOC as before)

If you have experience using hand-held or table mounted routers, IMO a good way to get started would be to program the machine to do what you’d do with them. For endmills/router bits less than 1-inch diameter, you’d probably max out your router speed and use depths/widths of cuts (DOCs/WOCs) and feed rates (FPMs) that don’t require much effort. You’ll be making dust rather than chips, but that’s ok/good for wood. If you start burning, just increase your feed-rate and reduce DOC, WOC, and/or FPM proportionally if necessary to keep machine forces reasonable. In addition to minimizing cutting forces, maximizing spindle speed maximizes cutting power availability.

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A spindle (and a water-cooled one at that) is a great way to have a quieter machine, and in some cases a lower runout for detailed work with very small tools. But DOC, that is pretty much bounded by the machine’s rigidity limits and the rigidity of the workholding.

I have the Pro XXL with the Z-Plus, so it’s not all a loss. There is a noticeable “slop” in the collet, I haven’t measured, but probably on the order of a few mils. I ate through a couple 1/32" end mills quickly in some pine, guessing that would have something to do with it, as doing more detailed work with the rest machining in CC v7 is something much easier now (as working times are cut way down from doing jobs with just a single, small, end mill.

This seems to be a topic that is commonly hard to bite into for many new people. Is there an online course or series, including paid, that would be suitable for this sort of market? I figure such things exist for the CAD side of things, this would be another itch needing to be scratched.

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“slop” as in “if you try to wiggle the collet with two fingers there is slop” ? There shouldn’t be.
Runout is a different matter, usually you can’t see it with you eyes, you have to measure it with an indicator. Runout can be a problem when it exceeds a few percent of the tool diameter, which means that the actual load on the tool will vary during the cut, produce excessive deflection, and eventually break the tool (especially so for small ones like 1/32")

Do you mean runout specifically or CNC in general ? There are a gazillion videos on youtube, but I have still to find a comprehensive online course that would address hobby CNC / wood (machining metal is something that is covered better, but often with much larger/heavier machines in mind). It’s part of the reason why I embarked on the journey to write the shapeoko ebook (that Nick linked above) at the time.


I just measured with a caliper using the .25" probe, getting about 0.015" of wiggle from far left to far right, about 1.15" of probe extending from the collet.

Do you mean runout specifically or CNC in general

More referring to speeds and feeds, but could be a CNC-woodworking, hobby/prosumer level course. Take your product for instance, it’s miles beyond the 3018, and it is certainly capable of putting out items that fetch money. I’m not expecting anyone would build aircraft parts with it in a Boeing shop, but in my mind, it’s not exactly a “toy”. As far as the course idea, I do see there are plenty of resources out there, but I’m sometimes a bit wary of just taking in info off youtube if I’m unable to verify it in some fashion, and don’t have pre-existing knowledge. In other disciplines, I’ve seen people who clearly have no idea what they’re doing putting out videos for beginners, and getting tons of high fives and thanks from those new guys, who just don’t realize that they’re being hoodwinked.

I wouldn’t expect to become an expert, but I’d like to get to the point where I know that I’m pushing my machine at an adequate pace, not burning bits out, etc. The guy who made G-Wizard (so I’d guess he has some chops, but can’t personally guarantee) made it clear in his writing that just going by sound is bunk, or there would be an audio portion to an interview at a machine shop.

One thing, for instance, I noticed recently is I did a 3d surfaced 14" tall replica of the National Parks Service logo, and the final 3d cut took a lot deeper cuts with the default CC tool library on a 1/16" bit than the 1/4" rough 3d did. It came out really good, didn’t seem to be making the carbide router sweat, no chatter sound, or anything like that. It makes me think that the 2.5D settings could use a little amping up (as you suggested above), but I just have no idea how hard to push, etc.

Perhaps an easier question is what gives first? The bit (up to 1/4"), the mill, or the gantry (or another option)? What are the tell-tale signs that you’re pushing way too hard?

I had a similar amount of vertical play and about 0.003" of horizontal play in the router shaft on mine. It came from the bearings. My best guess is that the bearings in these trim routers are not as good quality or rated for the duty cycle that the bearings in true spindles are. It is probably a mixture of both. There was an immediate improvement in surface finishes and accuracy when I switched to the spindle. For reference, I almost exclusively cut aluminum.

On a Pro XXL I bet that the first thing to give when using a 1/4" end mill would be the steppers. Audio is not always a great indicator but in this example, you would hear it. Depending on the material, I would guess that you would hear the spindle bogging down a bit and then the steppers would start skipping steps. An 800W spindle and a Shapeoko Pro are very well matched in capability so it is a little difficult to guess what will give out first. Before hitting this extreme you would see surface finish problems, even in wood. There would be obvious vibrations showing in the cut surface.

Learning how that Excel workbook I linked works is a pretty good way to understand the limits of your machine and how they interact with different materials. You can adjust it to fit the parameters of your spindle. The only way to know at what feeds and speeds you start to have problems is to find those problems. This is because it is so dependent on your end mill, the material, your workholding, where on the machine you are cutting, your dust extraction and the geometry you are cutting. The more you find the limits, the better you will be able to predict how far you can push the machine on new jobs.


That’s definitely too much, It’s 50% of the diameter of a 1/32" endmill, no wonder you broke some. Maybe check if the collet taper is not dirty or check another collet if you have one. Or if you can measure runout inside the collet taper to be sure ?

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I can feel as much wiggling the nut. I have two 1/4" collets and one 1/8", it’s pretty consistent across them. I have my 800W spindle, VFD, and all the rest in hand, just gotta assemble this week. Should have a decent compare/contrast at that point. Given that the parts are in hand, the money is spent, no reason not to use them, even if it doesn’t turn into a night and day difference from what a carbide router optimally should perform at (vs what I’m seeing).

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