How to evaluate endmills before and after purchase?

I’ve been looking for endmill suppliers and there are plenty but I’m a bit lost on how to choose.

When it comes to base specifications I think I’m largely fine. Flute count, angle, coating, shank, diameter etc., I know what I want.

What’s got me confused is that prices for “the same” endmill are all over the place. One supplier might offer an endmill for $4, while another offers “the same” for $10 and yet another for $30. These are all EU/US tools, no Chinesium involved, though brand vs. no brand is a thing.

So what are the differences between these endmills? I can offer examples if needed.

And then the next question, if I have a selection of endmills, how do I compare them? Should I expect different endmills with similar specifications to produce different surface finishes? To handle feeds and speeds fairly differently? To wear differently?

To make the question easy, what’s the objective difference between a Chinesium endmill and say Harvey Tool? Not “you get what you pay for” or “consistency” but if I have one of each sitting next to each other on a bench, why should I reach for the Harvey Tool?

They may be US distributors, but I’m sure they aren’t all made in the US. Grades of carbide can vary dramatically. The sharpening of the bits can also vary widely. That being said, this is wood you’re cutting for a hobby. I usually go with the cheaper bits, unless I have reason to get better bits.

The difference will probably not be seen by a hobby user in wood or any non-metallic material. I would expect a higher end bit to hold and edge longer, and achieve a better surface finish… but in terms of surface finish, it will probably not be noticeable on wood.


I have some Frued bits that work very well. I also have a few Irwin but Irwin has stopped making router bits. I also have some Amazon specials as well as Whiteside. The ones I bought from Carbide are price competitive and seem to be excellent bits. My Frueds and Whiteside bits are also top notch. I have a lot of Whiteside that I use in my router table.


Metal for me, so things aren’t as simple unfortunately.

But what makes them “excellent” or “top notch”? Do they make cleaner cuts? Last longer?

The Frued bits are 90 and 60 degree v bits and they cut very cleanly and seem to last a god while. I did have one Frued 90 degree loose its tip but I am pretty sure that was because of a crash I caused. The Witeside bits cut very cleanly and they have excellent customer support for F&S questions.

You are correct I cut wood only and not metal. For Alum many rave about single flute mills and seem to love them. Do a search about cutting alum on the forum and you will find the metal cutters recommendations.

For metal, the differences are pretty significant, at least on a Shapeoko. On a bigger, stiffer machine with flood cooling, it doesn’t matter as much.

  1. Endmills for steel are ground with less rake (say 7 degree or so) than those specifically for aluminium (15 - 20 degree rake angle). More rake means much lower cutting force, but also a more delicate edge that would be damaged quickly in steel. Lower cutting forces mean that a less rigid machine can take a more aggressive cut before chatter onset. Therefore, if an endmill is advertised as “general purpose” or “aluminum and steel”, don’t buy it, it won’t work as well as it could in neither of them.

  2. From the tools I’ve tried, it seems that mirror-polished flutes help - and this is usually visible on product photos (look at DATRON, for example). The extra polishing step obviously costs money.

  3. Geometry details: More expensive endmills may have a shorter length of cut (APMX) and instead a neck above the flutes that is ground to slightly smaller diameter (say D - 0.3 mm or so). This is useful because the section of the tool that is weakened by the flutes is shorter, while you still can reach down into a pocket without the tool shaft rubbing on the walls.

  4. If your airblast setup or vacuum-hose-kung-fu are not top notch, really prefer single-flutes for much less chip evacuation trouble.

Summary: Go with endmills for which the rake angle (gamma) is specified (SECO, Coromant, Dormer-Pramet, WNT, Ceratizit all do this) and fairly high (>15degree) for aluminium. Polished flutes a bonus. Preferably single-flutes unless decent air-blast is present.


The endmills from Carbide 3D have the following desirable characteristics:

  • made from U.S. sourced carbide, so have a fine, regular grain structure which should make for a longer-lasting edge
  • machined in the U.S. so should have a fine, sharp edge, and uniformly and regularly shaped flutes

Inspecting your endmills with a loupe may be informative, and see:

That said, many folks are very successful with inexpensive tooling, even in metal — the proof is how an endmill cuts, and I’ve always recommended considering starting with inexpensive tooling for small sizes which are likely to break — just make sure that they cut well in a piece of scrap at the feeds and speeds you’re using.


To be clear, the question isn’t so much “which endmill should I buy for which metal” but “between two Aluminium endmills with similar specifications, why the difference in cost”.

To give a more solid example, here in Europe, if I want a 3mm single-flute endmill for cutting Aluminium, produced in the EU, I can buy from Sorotec:

The differences between different endmills by the same manufacturer are fairly clear. Polishing, coating and extra precision cost money so the price is different.

But why are the DATRON and FIRSTATTEC polished endmills roughly 2x the price of the Sorotec polished endmill? They’re all made in the EU.

It gets weirder when you look at different retailers. One of @Julien’s suppliers offers much cheaper products:

And again, I believe these are made in the EU from high-quality carbide (though I don’t speak French, maybe I’ve misread somewhere).

Closer to home, the more “professional” oriented Swiss suppliers offer more expensive options:

Why is the DIXI endmill so expensive? It’s even more expensive than DATRON.

When you get into the higher flute-count endmills things get even more crazy.

The factors you mention are more what I’m talking about but what makes a Carbide 3D endmill different to another endmill machined in the US from US carbide? For example this Sandvik endmill costs ~$52 USD while Carbide 3D’s single-flute endmill with coating costs $30, nearly half the price


I’ve exhausted what I know/am cleared to say — you’d need to get someone who has tested lots of endmills to comment further, maybe @wmoy could chime in?

One company which has pretty exhaustively examined endmills and their usages seems to be Precise Bits — I can recommend their products whole-heartedly, and their website has lots of information:


They seem much more geared towards softer woods and plastics though, rather than metals?

At the hobby level, on a desktop CNC, a higher quality endmill may produce a marginally better finish (still never going to be mirror smooth, and you need to still be using the right materials, have solid workholding, and other fundamentals down pat). It may last slightly longer (you should still get many dozens of hours of use out of any tool in anything other than steel).

Bottom line, unless you’re a production woodshop abusing your tools for hours a day, it doesn’t matter what you buy. A pro with an cheap tool will get more utility out of that endmill than a noob with an expensive tool. I frequently buy ebay tools to test and see if I actually need a tool like that (random size downcutting endills, compression, single flutes etc) before shopping with trusted vendors. And I really don’t worry about “cut quality” of a particular tool because it’s far more a factor of your settings than the tool until you start running CNC’s that cost several times more than a Shapeoko.


Thanks! Does that apply to cutting metal on the Nomad as well? The Nomad is meant to be a much more rigid and precise machine than the Shapeoko, does that affect its sensitivity to endmill quality?


At the end of the day, the vast majority of tools will work. The bigger impacts on quality will be from tool geometry. Single flutes get you great chip evacuation. high helix angle might be better for wall finishes in some case. How well the manufacturer balanced things like size of the flute vs strength of the carbide will determine how hard you can push it, or chances of survival if you have a oops-moment. Reputable manufacturers do their homework, cheaper manufacturers imitate and may or may not get it right.

But again, these differences are all fairly subtle at the hobby level. Investing in your own skills is just as important as investing in good tools.


Oh, that small - 3 mm… those have an uncanny ability to snap off pretty quickly, so just like @wmoy said it’s maybe not wise to invest too much in the beginning.

I’ve used (and broken) some of the sorotec 3 mm “alu” 2-flutes and they work absolutely fine with the settings from their website and very small engagement (ap 4, ae 0.2 mm), finish is pretty good. Their store-brand 6 mm “alu-standard” short 1-flute is actually very robust (ap 7 ae 0.3 fz 0.07 mm).

Your Sandvik endmill has a 6 mm shaft (DCON on that page), the rest are straight 1/8". The additional stiffness does make a difference if you aim for high productivity - but then you probably have another machine (and buy at half that price or less anyway).


Don’t endmills designed for high cutting speeds (HSM), like some of those listed above, differ from “standard” endmills in cost, performance, and usage?


I spend about $100/month on endmills, which isn’t alot of endmills. A wholly arbitrary allowance I created. I just cut things with them, and see what they do. I contact my suppliers, and I ask them what they use on their industrial machines. Then I contact the tool manufacture, they fill in any gaps, and I order a variety. I find it an interesting aside to making things. I’d say my average endmill is about $30. I’d say there is considerable differences in some of them, even though they were designed for the same purpose, which in my case, is plastics.


That seems pretty expensive. Do they cost this much just because you’re interested in looking at expensive endmills or have you found that expensive endmills work better for you? If they work better, how so?

I suppose it isn’t cheap. But, I am fairly certain that everything I have in my shop, and still on my desk to be entered in my Fusion tool library, is domestically manufactured here in the US. I generally expect to pay more for this, and in certain cases, happily do. Not much vanity to be had from an endmill, so price point is just a matter of what has been recommended to me. The recommendations originate from Chemcast. KING, and the like, plus the distributors I purchase from, and the companies I contract machine work to. All of which have massive 24/7 fabrication operations. I buy thousands of dollars in sheet plastics every month, and they are all quite helpful with manufacturing questions.

I haven’t tried to purchase cheap variants specific to hard and soft plastics. Saving $10, even $20, on an endmill that is going to be used for countless operations, just doesn’t seem concerning with my throughput. It would seem my suppliers apply the same logic, but have the throughput.

Essentially I opt to spend money instead of time. I buy an application specific product from a reputable supplier, I trust their reputation and experience; I see value in that.

Just a little example - One of my most used endmills is a .25" single flute, bright, 21 degree helix, up cut. Retail is about $35. I could tell this endmill from a $40 .25" C3D coated single flute by sound alone. Both are US manufacture, both retain a premium price, but the design intentions are obviously different. I couldn’t tell you the helix of the C3D cutter, it isn’t listed, but I can tell you that is doesn’t compare in cut quality on a soft classification plastic.


For plastics we sell some Amana Endmills:

Don’t buy into false economy. Cheap bits are cheap for a reason. Nothing wrong for some uses cheap is ok. You don’t need to buy the most expensive just because they are expensive. You want goldie locks just right. Frued, Whiteside and Carbide3d are great bits and price competitive. The Amana are good but rather expensive for me.

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